How to Build a Water Cooling PC: Ultimate Step-by-Step Guide

how to build water cooling loop pc

Water Cooling 101, Pros & Cons, Air Cooling vs Water Cooling, Types of Water Cooling, & How to Plan and Install Your First Custom Water Loop

Last Updated: Mar 5, 2018

Ahh, good old water cooling. Nothing cooler in the DIY world, pun intended. If you're up for the challenge this complete beginner-friendly step by step guide may very well become your best bud over the next few days or weeks.

Water cooling isn't for everyone though, so if you're brand new here then perhaps bookmark this guide for a later date as custom water cooling is a luxury feature and definitely not practical in terms of trying to build the most cost-effective build.

This tutorial will cover absolutely everything you need to know on how to build a water cooling PC as a hardware beginner. First you'll learn the basics of water cooling such as how it works, why it may be a better option than air cooling, and the different types of water cooling.

Then we'll get to designing and planning your first custom loop, choosing the best water cooling parts and accessories, where to buy components for your particular country, and then actually installing all of your parts carefully and correctly the first time around. 

Lastly, we'll get into how to maintain your new custom water cooling system. Move through this tutorial at your own pace, good luck, and let's dive into the deep end of the DIY world.


Water Cooling 101, Pros & Cons, Air vs Liquid Cooling


Plan a Custom Loop, Choose the Right Parts, & Buying Tips


How to Install Your Custom Loop & Maintenance

PART 1: Water Cooling 101, Pros & Cons, Air vs Liquid Cooling

If you've ever been curious about water cooling, whether adding it to an existing PC or building a brand new water-cooled setup from the get-go, this guide will cover all of the basics that you need to know to get started. Water cooling is not for everyone as it has advantages and disadvantages.

It can be quite complicated and time-consuming to get started with, but keep in mind there is also the easy, hassle-free way to get your feet wet with water cooling in the form of pre-built, closed-loop liquid coolers which we’ll also cover in this guide.

In this first module we’ll cover how water cooling works, the benefits and potential downsides, the different types of water cooling, and all-in-one liquid coolers.

Then in the next module we’ll explain the parts needed for custom loops, and tips on how to best select those parts for your particular setup. Lastly, in the third module we’ll cover the basics of how to actually put together your first custom water-cooled loop.

What is Water Cooling?

PC hardware can generate a ton of heat, especially when under heavy load and/or when you overclock your components to push them to their limits. The standard way computers cool down your components to keep them safe and running well is by moving air, such as with a typical heat-sink-and-fan combination.

But when it comes to cooling, water is on another level of effectiveness because it has a high thermal conductivity meaning it can absorb heat easily. With water cooling solutions, water is actually run over your components, transferring the heat those components generate to a radiator that then dissipates that heat.

Water cooling not only reduces heat more effectively and reduces/eliminate noise (fans can be loud when working hard) but it can also increase the maximum performance you can squeeze out of your computer via overclocking.

With a well-designed water cooling setup, enthusiasts looking to overclock their components to the limit will have the ability and safety net to push their parts to run faster than with standard air cooling.

Whilst custom water cooling setup are usually only tackled by power-hungry users with large budgets who are building a monster system or interested hardware enthusiasts who perform highly demanding tasks with their computers such as intense overclocking, using water-cooling in your PC doesn’t have to mean you go all-out and design and implement a custom loop.

You could simply go the much simpler, common way of using a pre-built, closed-loop CPU liquid cooler (also called AiO liquid coolers; “All in One”) which we will also talk about in this guide. But overall, nothing beats a full custom loop for maximum cooling capacity, effectiveness and noise elimination. Oh, and aesthetics; a custom loop adds a really unique touch to any build.

Air Cooling vs Water Cooling

To compare air cooling and liquid cooling your PC hardware components, we'll use the CPU as an example which is the most commonly water-cooled piece of hardware. Keep in mind though that with custom water cooling setups you can water-cool pretty much any component that your heart desires.

With a standard, air-cooled CPU, the heat generated by the processor is transferred into the heat sink. The fan sucks air past the heat sink, drawing heat away from the heat sink as it does so. The hot air is then pushed out of your case through the rear by your case fans.

As for a water-cooled CPU, instead of air being used to transfer the heat generated by the CPU, water is used.

The coolant is pumped through a tube and the heat is transferred through an inlet into what's called a cooling block, which is basically a hollow heat sink, and then the heated coolant is pumped into a reservoir and then into a radiator which is then cooled by a fan. The coolant than continues its merry journey to the cooling block and the glorious cycle continues.

As mentioned, water cooling is more effective and quieter than standard air cooling, but air cooling is still the most common method used in computers today. As time goes on who knows whether that will change as water cooling becomes more easily accessible to everyday consumers, but for the time being water cooling will remain a luxury.

Types of Water Cooling

At the most basic level you have pre-built, AiO (All in One) water cooling solutions in the form of liquid CPU coolers such as Corsair’s popular Hydro Series.

This is the simplest and easiest way to break into the world of water cooling. Research is as quick as finding the best model for your CPU that will fit in your case, and installation is as easy as installing a standard air cooler.

An AiO (All-in-One) Liquid Cooler

Performance of AiO CPU coolers will outperform air coolers, and in recent years they've become quite popular choices among the mainstream PC building crowd putting together mid to high-end gaming systems.

AiO coolers will only take you so far though, and the next level of water cooling is to build a custom loop which is where the real fun beings.

This has many possibilities and is the best way to keep temperatures down as much as possible across your entire system, but it comes at a cost financially and time-wise as it's a lot more complicated to setup than a simple AiO.

With a custom water cooling loop you have the choice to basically cool any component that tickles your fancy, whether that’s your CPU, your graphics card/s, and other components such as your RAM, motherboard, and even your storage devices can be included in a water loop.

Potential Cons to Water Cooling

First let’s look at the potential bad news; while water cooling sounds like the coolest thing ever, pun intended, there are some potential downsides to consider.

Although, it’s fair to say these drawbacks aren’t really an issue for patient enthusiasts with a healthy budget who also find this kinda stuff fun, but it’s worth discussing both sides of the coin.

First of all, besides AiO liquid coolers like Corsair’s Hydro range and NZXT’s Kraken series, custom water cooling is obviously more complicated to plan, setup and maintain.

There's quite a few more parts that go into it compared to a standard PC build, many more little nuances and details to think about, and therefore more that could possibly go wrong.

Maintenance isn't THAT involved to be honest, as coolants probably only need to be replaced about once a year or so in a typical loop, but it's definitely more maintenance than a standard PC build.

As for worst-case scenarios like water leaks which could damage your entire system, it's a very rare thing if you set things up properly, but it can happen so there's that risk to take into account.

Price is also another downside as water cooling parts can add up in cost quite fast, especially if you buy premium. Even a basic custom water loop will set you back at least a few hundred dollars on top of the cost of your PC.

Potential Pros to Water Cooling

As for the advantages, well for one it's pretty freakin' awesome and I can't imagine anything more satisfying within the hardware community than having successfully built your own custom water-cooled machine.

You'll be in a rarer, elite category of PC builders that had the courage and the know-how (and let’s face it, the wallet) to make it all happen.

Looks pretty darn worth it to me.

And besides the benefits we've already mentioned such as water cooling being the most effective cooling method for your hardware at the lowest levels of noise (or should I say whisper silent), it also looks seriously cool in action.

For many enthusiasts who venture into water cooling territory, the unique aesthetic possibilities of a water-cooled PC is a big drawcard. A well kitted out air-cooled PC can look pretty damn awesome with the right combination of parts and accessories, but water cooling is the pinnacle of PC looks.

On top of having the most effective cooling, lowest noise, and best looks, water cooling will also lengthen the life of your components as they’ll be running as peak efficiency thanks to the lower heat and noise.

Lastly, with a well water-cooled rig you have the ability and safety net to overclock your parts further than you safely could otherwise, so water cooling could indirectly allow you to build a higher-performing PC overall.

PART 2: Plan Your Custom Loop, Choose the Right Parts & Buying Tips

Now we get to the good stuff and the heart of PC water cooling; custom water loops. They're quite involved, as you'll see by all the various pieces of the puzzle that we'll explain here, and we don't recommend creating one unless you have the interest, time, money and patience to do your own thorough research to design and install the right setup for you, and to do it right.

Keep in mind there are all-in-one kits that can save you time and money as well, but here we’ll explain how to setup a fully customized loop by sourcing each part individually which gives you the most control.

As we go through each individual component of a custom water system and what to look out for when selecting the right one for your setup, keep in mind this is just an overview and you should do your own extra research to take into account your specific aims and needs. Each loop is a little unique and we won’t be recommending specific parts here, but researching and designing your own custom loop is part of the fun.

This introductory guide is meant to set you off on the right foot, but don’t let your learning stop with this guide as water cooling has many little nuances and technicalities and is the type of thing that needs to be thoroughly researched for your own situation if you are to pull it off effectively.

Planning Your Loop Complexity

Before we get into explaining each of the parts that make up a custom water cooling loop, and tips on how to choose/buy them for your particular needs, you should plan out the general design of your loop.

This applies whether you’re adding a custom loop to an already configured PC build, or you’re planning a fresh new computer from scratch that will have some awesome water-cooling from the get-go. You can make your loop as simple or complex as you like, and the possibilities these days are endless and you can water-cool just about anything besides your toaster.

Your most basic option is to set up a single loop that just cools your CPU. This is the first step up from using a pre-built/closed-loop liquid cooler, but is still relatively simple to undertake as a beginner.

This first stage of a custom water cooling PC will still include all of the core parts that make up more complex loops; you’ll need a water block for your CPU, radiator, reservoir, pump, tubing and fittings.

If you’re brand new to the water-world and not wanting to delve in too deep (pun intended) then this is a good place to start as you’re limiting potential problems and you’ll gain some confidence in the process.

It’s also going to save you money as you won’t have to shell out a ton of cash for additional parts, and you can always add to your loop later.

There are also all-in-one kits for this type of basic water cooling setup too, so you may want to look into them too if you wish to really keep things simple.

The next stage in complexity for custom loops would be to throw a graphics card into the mix. For this you’ll need a suitable GPU water block, and possibly a larger radiator than the one that would have been used for a CPU-only loop. Or, you could add a second radiator instead to increase the overall cooling capacity of the loop.

Beyond that and you have the option to include other components such as the RAM and motherboard to the loop, which will all need their own water blocks of course, and then going even further than that and you get into dual-loop territory for advanced enthusiasts.

Having two separate loops isn’t something we’ll be covering in this guide, but just know it’s out there and a possibility should you want to go all-out with building an epic water-cooling monster someday.

Now let’s get into choosing each of the parts you’ll need for a typical custom water cooling loop.

How to Choose a Water Block/s

A water block is something you mount onto each hardware component that you wish to include in your loop, and is used to transfer heat energy from that component and into the water in your loop.

Example of a CPU water block.

Water blocks rely on surface area to exchange heat effectively, with more surface area equaling more heat being transferred and therefore more effective cooling.

Water blocks can use either pins, fins and/or channels to increase surface area to increase effectiveness, with common CPU water blocks typically using pins and fins. GPU water blocks come in two varieties; full cover and universal blocks. Full cover blocks will fit the one specific GPU model while universal blocks will, you guessed it, fit a variety a different graphics cards.

Example of a GPU water block.

Motherboard water blocks are like GPU ones; they have universal and model-specific versions. RAM, storage drive, and even PSU water blocks are out there, but rarely worth it, and only the most hardcore enthusiast would consider getting blocks for these components. Including these components in a water cooling loop would be more for looks than practicality.

So, you’ll need a suitable water block for every component you want to include in your loop. If you can’t find blocks that fit your particular parts for whatever reason, then I’m sorry to be a dream-killer but your water-cooling aspirations may not be possible. But don’t worry; most common, modern parts will have suitable blocks for sale somewhere.

Here are some things to keep in mind when on the hunt for the right water blocks for your CPU/GPU/other parts:

  • Ideally you should look for a water block with a high-flow design and low hydraulic restriction.
  • Water blocks for CPUs tend to support either Intel or AMD CPUs, but some will support either. Either way don’t forget to check it supports your CPU’s socket type, and ideally your specific CPU model too (but socket type should be all you need).
  • Search around online for reviews and extra advice before buying a water block to foresee any potential problems you might have with it.
  • Make sure the water block/s you buy comes with all the pieces you need to install it, such as a backplate, mounting mechanism and mounting screws etc, otherwise you’ll have to source these yourself. 
  • You’ll also need thermal paste just like when installing an aftermarket CPU cooler; some blocks will come with some, some won’t, and some blocks might have it pre-applied. Yes, you’ll need thermal paste for a GPU water block too, and not just for CPUs.
  • For cooling a GPU, a full cover block (as opposed to a universal block) is the most effective, best-looking, yet most-expensive option. It may or may not cover your entire card, but either way it’ll cover all the important bits of the card that needs to be cooled. Full cover GPU blocks will only support the one specific GPU model.
  • To reduce corrosion you should stick to blocks made of the same metal; if you have a copper CPU block then try to also get copper for your GPU block.

How to Choose Your Radiator/s & Fans

Radiators function to keep the water cool as it moves around the loop. It does this by exchanging heat with the surrounding air via the copper fins that make up the radiator’s core. Heated water flows through these fins and are cooled by the radiator’s fan. They come in various shapes, sizes, thicknesses and fin densities.

In general, the bigger the overall surface area of your radiator, whether that’s one big radiator or multiple smaller ones, the more effective your loop will be dissipating heat, which also leads to less noise as fans can be run at slower speeds (the faster fans rotate, the nosier they can be).

You have to choose a radiator (or multiple radiators) that’s going to comfortably fit in your case. A good rule of thumb to follow is to shoot for a minimum of 120mm/140mm of radiator surface area for each component you are cooling in the loop, and to add another 120/1400mm if that part will be overclocked.

For example, if you’re designing a custom loop with only an overclocked CPU to be included in the loop, you’ll need 240mm of radiator space, whether that’s 2 x 120mm radiators or 1 x 120mm radiator.

The thickness and fin density of your radiator, measured in FPI (fins per inch), are also fairly important considerations and will dictate what type of fan you want to use on your radiator. Thickness is measured in mm and can range quite a lot from say 20mm to all the way up to around 80mm.

The higher the FPI of a radiator, the higher the static pressure you'll require to effectively circulate cool air through that radiator. An FPI of 30 and above is on the high end, while 10 and under is considered low.

A radiator with a high FPI of over 30 should ideally be paired up with static pressure optimized fans, while lower FPI radiators of say under 15-20 may not see much of a difference with static pressure fans (over airflow fans).

Radiators also have other features such as Crossflow, where there's an inlet on either side of the radiator, as opposed to the standard inlets on the one side, which may help some water loop setups. Some radiators also have various fin materials which can improve performance.

Then there's shrouds which are often made of plastic and used to separate the fan and radiator by roughly an inch or so to decrease the size of what's called the “dead zone” - the place of no air that a radiator-mounted fan has. Enthusiasts also use them solely for aesthetic purposes as well.

How to Choose a Water Cooling Pump

For a custom water cooling setup you'll need a pump to circulate the coolant around your joyous merry-go-round loop of glory. Pumps are the heart of a water cooling configuration and come in all manner of different designs and sizes with varying power requirements and noise output. It's a basic yet crucial component that sets the whole thing in motion, and the more components you wish to water-cool, the stronger your pump needs to be.

The flow rate of the pump measures how much water your pump can circulate without restriction, and is a fairly important consideration to account for.

However, the maximum flow rate of a pump that manufacturers mention on their products assumes a zero static head pressure, meaning the actual flow rate would be quite a bit lower than the maximum listed flow rate.

The most common type of water pump these days is called a DCC pump, which is the most cost-effective and is generally highly reliable with only the single moving part, although there are more powerful pumps out there for more involved, high-end custom loops.

The thing is though, if you want increase cooling performance, you may be better off getting a bigger radiator instead of a stronger pump. As always, don't take our word for it and do your research.

How to Choose Your Reservoir

In a water cooling loop a reservoir is used to hold the coolant in the loop, making bleeding out bubbles easy. In other words, it allows air bubbles to slowly be replaced by water as it circulates. It's also the filling point for the coolant.

Reservoirs come in stand-alone form or as a pump and reservoir combination. Most are designed to be mounted inside your case, while others are mounted inside a 5.25 inch external drive bay. Some reservoirs also come with pump mounts and other handy features that may come in handy for your particular setup.

A reservoir is not technically required for a complete, working water cooling loop but having one is definitely recommend as they can help reduce temperatures and they make filling and bleeding the air out of your loop quite a bit easier.

Choosing Your Tubing, Springs & Coils

The function of the tubing part of a water cooling setup is pretty self-explanatory, and is what allows the coolant to flow around through all the parts of the system, however it does come in many different types, materials and sizes and so there are a lot of options to consider.

The first thing to consider is whether you want to get soft or hard tubing. Soft tubing is more flexible, easier to bend, cheaper and easier to work with so is suggested for beginners.

Hard tubing requires more work and will need to be heated and bent into shape to reach your fittings, and is only recommended for more experienced hardware enthusiasts or beginners willing to put in the time.

When it comes to size, tubing is measured in three ways:

  • ID - Short for Inner Diameter, this is the diameter of the inner wall of the tubing and is commonly 1/2 inch, 3/8 inch or 7/16 inch.
  • OD – Short for Outer Diameter, this is the measurement of the outer wall of tubing with common sizes being 1/2 inch, 5/8 inch or 3/4 inch.
  • Wall Thickness – The difference between the OD and the ID (in other words; OD minus ID).

The tubing you get will be based on both the space you have inside your rig as well as personal preference. Oh, and your budget too, as tubing can really add up if you go for premium-quality.

You’ll want to make sure the tubing you get will work with the fittings you get, and that the ID and OD of your tubing is compatible with the ID and OD of your fittings (we will talk a bit about fittings in a bit).

This basically means that they should be the same measurements, however you can generally use tubing that’s smaller than your fittings for a tight fit. If you’re going to be using 1/2 inch tubing or larger, you’ll probably need to get clamps to hold them in place.

Tubing also comes in various material types:

  • Vinyl – The cheapest option and recommended to avoid if you can as it can quite easily create kinks.
  • Clearflex – Better than vinyl and a nice middle-ground option.
  • Tygon – The most expensive yet highest-quality, most flexible option for tubing.

What you can also do with your tubing, if you opt for the most economical materials, is add springs or coils made of plastic to the inside and outside of the tubing to keep it round. Springs that go on the inside of the tubing (yet hardly hamper water flow) must fit the ID of your tubing. The coils will go on the outside (and are sometimes used for aesthetic reasons as well) and will need to fit the OD of your tubing.

As for the length of tubing to get, that will depend on your particular setup, but in general you may need around 5-10 feet of tubing for a typical loop.

Ideally, you’ll want to get a little extra length than you think you need to have some available headroom, and you may want to get an extra couple of fittings than you think you’ll need too.

It would be annoying going to put your system together only to find you’re missing a bit of tubing or a fitting and having to re-order and play the waiting game.

Choosing Your Water Loop Fittings

Your fittings are what allow you to connect your tubing with the other parts in your water loop, and they come in various shapes and sizes.

Their style will also depend on whether you’re using soft or hard tubing, and in general you’ll be needing two fittings for every part of your loop (ie your water blocks, radiators, reservoir etc).

When it comes to choosing fittings you have the option of either barb fittings, which are basically just a spout that fits onto your loop parts and are the economical option, or compression fittings which are like barbs but with a compression ring on the outside for extra security and a tighter fit.

Compression fittings are more expensive but look better, and they come in either a traditional or acrylic style, with acrylic fittings designed to be used around hard tubing. You can also get angled fittings which can improve the aesthetics of your loop.

When looking for barbs you’ll need to make sure the ID of your tubing matches the barb size. As for getting compression fittings, you’ll need to check that both the ID and OD of your tubing will be compatible.

Choosing Your Coolant & Additives

Now to the actual liquid that will be flowing around your loop, coolant is made up of distilled water and additives that kill living organisms and prevent corrosion, and you can either buy specific water cooling coolant or you can buy the additives separately and make up your own.

If you go the do-it-yourself route then make sure to use distilled water as tap water can contain impurities that may cause algae to grow in your system which could clog tubes and corrode the water blocks.


As for the additives to add to your distilled water, a couple of popular options are Biocide and Silver Kill Coils. With Biocide you add a few drops in the water and it’ll prevent anything from growing, with PT Nuke being a good, popular brand.

On the other hand, a Silver Kill Coil is a small piece of silver that you place inside your loop where the water flows that will also prevent life growth (because silver is a natural biocide).

As well as either Biocide or a Silver Kill Coil, if your custom loop contains more than one type of metal then you’ll want to add an anti-corrosive product to your coolant to, you guessed it, stop corrosion.

For example, if you’re using a copper block along with an aluminium radiator, you’ll want to add an anti-corrosive. A good brand for this is Fesser Base.

While not necessary, some people also like to add a hint of dishwashing liquid which can help get rid of bubbles and acts as a surfactant (which is, to avoid getting too technical, something that lowers the surface tension).

As for adding coloring to your coolant; it’s a mixed bag as it can very well cause your system to gum up. If you want a colored water loop, the most reliable option is to get colored tubing which still looks awesome.

If you do get colored coolant, do your research as to what others have been experiencing with that particular product.

How to Pick a Suitable PC Case

Don’t forget that your selection of case is an important part of building a water cooled system, as you’ll need to find one that can accommodate all the parts of your custom loop, and that doesn’t make building your loop too difficult as it’s complex enough as it is.

Your case will need the extra room for the radiators; with a standard air cooled system your case only needs fan mounts and 25mm of space as most case fans are that thick. But water cooling radiators start at 25mm thickness and can go all the way up to 80mm, so you need to take that into account plus the extra space for the fans as well. You also need more room for the reservoir, pump and tubing.

When choosing a case for a water cooling system it’s not just the size of the case that’s important but the internal layout. In fact, it’s possible to use a mini case for water cooling if it’s designed well, although in most cases you will want to get a mid tower at the very least with a full-tower being ideal for the most flexibility.

You want a case that’s actually designed with water cooling in mind, and sticking to brands like Phanteks, Fractal Design, Corsair, In Win, Caselabs, and NZXT who are known to produce great water cooling friendly cases is a good idea. Other brands may also have suitable cases, but the brands just mentioned are among the best of the best when it comes to water cooling setups.

You’ll have to do your own thorough research on the exact case you choose to make doubly sure that it’s going to suit your exact custom loop without issues. A good place to start is to check out the water cooling builds of others on sites like PCPartPicker and see which cases work well for others and compare their setups to the type of setup you’re wanting to create.

Where to Buy Water Cooling Parts

If you’re going ahead and building your first custom water cooling machine, to recap these are the required parts you’ll need for a working loop. Note that a reservoir isn’t technically needed but recommended:

· Water Block/s

· Radiator/s (with fans)

· Pump

· Reservoir (or pump/reservoir combo)

· Tubing (soft or hard)

· Fittings (2 per item)

· Coolant (distilled water + additives or kill coil, or special coolant)

It’s imperative you do your homework before buying anything to make sure you’re getting the right parts that are all compatible with each other and with your case. Don’t rush into buying anything, take your time, and enjoy the planning process and picking out each part that you need.

Take your time to make sure you know what you need and what you’re buying is going to work well, and take advantage of things like bundled-together water cooling kits, getting help from experts on forums, using a component selection tool like EKWB’s configuration tool, and/or reading about other people’s successful water cooling rigs online.

In this guide we won’t be recommending specific brands or parts as that’s totally up to you and every water cooling setup is unique. Plus, choosing parts is part of the fun and also helps you understand the process which will help come installation and maintenance (and for future installs).

Best Water Cooling Stores

We’ve listed some of the current most popular stores across America, Canada, Australia and the UK where you can buy a good range of water cooling components. If your country is not included, note that some stores like do ship internationally, otherwise try to find local or online stores in your particular country. 

PART 3: How to Install Your Custom Loop & Maintenance

What your collection of parts might look like. Let's do this!

Tools to Build Your Water Loop

Once you have all the parts you need for your loop and you’re beaming with excitement to finally put this thing together and claim your rightful place alongside the hardware elite, there are a couple things to know about first before you jump headfirst into mounting your parts.

One of those is to make sure you have everything you need to finish the installation process. It’s ideal to install a custom loop all in the one day so you don’t lose track of what you’ve done and what remains to be done, so if you’re new then make sure you have a nice chunk of time set aside to get your build finished.

Give yourself 4 hours minimum but you may very well need even longer for unforeseen obstacles you may have to work through.

Since building a water cooling loop is quite a bit more involved than a typical PC build, you’ll be needing more tools than you would normally need for a standard build, especially if you want to be fully prepared:

  • Screwdrivers – You may only need the one size as with building a normal PC (phillips-head #2) but it’s best to have a range of different screwdrivers as your water cooling installation may call upon them.
  • Allen Key – Also called Hex Keys, you may need this to tighten certain screws within your loop setup.
  • Measurement Instrument – You may need a ruler or measuring tape during the planning process to map out exactly where your components can fit.
  • Flashlight – PC cases can really block out light well, so get a flashlight and have someone to hold it for you if possible, or a get headlamp or adjustable lamp.
  • Paper Towel – To clean up any spillages you make along the way, and to dry your parts when washing them before installation.
  • Needle-Nose Pliers – A handy multi-purpose tool used for gripping, pulling, bending and cutting.
  • Funnel – Using a funnel makes filling and flushing your loop a lot easier. Make sure it’s big/small enough to fit inside the tubing size you choose.

Step 1: Build & Test Base System

If you’re adding a water cooling loop to an already functioning machine, don’t worry about this step, but if you’re building a new PC build from scratch then you’ll want to build your PC as per normal without the water cooling first to test that everything is working fine.

The last thing you want to do is build your PC along with your custom loop without testing your components, and then having issues with booting up and having to go back and undo the work you put in to install the loop to remove components for testing if they’re dead.

As well as making sure your PC is running without issues before going ahead and installing your loop, be sure your cable management is nice and neatly done so you don’t have any cables in the way, you have maximum room to work with, and your PC’s cooling is maximized.

Step 2: Plan the Installation

If you haven’t already done so, it’s the time to plan and think through your installation now, such as exactly where your parts are going to mount in your case, the order of your loop, and where your tubing will run. Knowing these things before you start will make the installation process a lot simpler and you’ll have a basic roadmap to refer to. It might help to actually draw a basic sketch on paper if that’s how you roll.

You don’t want to just wing the process and then find out you have to backtrack and uninstall your hard work and start something again. Even though you should already be fairly familiar with your case, as you would have needed to research its viability for your water cooling setup, now is the time to get fully accustomed with its inside and think about exactly where everything is going to go.

Water cooling setups are pretty flexible, but one thing you’ll definitely want to plan for is to have your reservoir sitting just before your pump in the loop order. This promotes maximum flow, encourages air bubbles to float away from the pump, and ensures the pump never runs dry.

Your case will determine where your reservoir fits, and you may be able to install it in a drive bay just like you would install a DVD drive. Alternatively you may need to mount it elsewhere and use Velcro or the mounting hardware it should have came with. Same thing with the pump.

Your water blocks will simply fit onto your CPU, GPU/s, and any other parts you’ll be cooling. Your radiator will usually mount either on the vent where your case fans would go or on the bottom of your case if it’s big enough. Otherwise you’ll need to mount it using brackets that should have come with the radiator.

After planning your loop to have the reservoir before the pump, you can basically map out the rest of your loop in any order that you wish, so keep it simple and do what is easiest to install, easiest to maintain, and looks the best to you.

You’ll hardly notice a difference in performance with different loop orders, unless you’re a high-end enthusiast creating an extreme and complicated setup and you care about the miniscule details and every little 1%.

In that case you also want to consider setting up a separate, parallel loop using splitters so that the last component in your loop doesn’t get the leftover heated coolant from all the previous parts in the loop order, but for most building a typical water cooling setup the order doesn’t matter so long as you make sure your reservoir is before your pump.

Step 3: Clean Your Loop Components

There’s no need for preliminary cleaning when installing standard PC hardware as parts are ready to install straight from the box, but when it comes to water cooling parts it’s likely (and recommended anyway) that you will need to clean your components first.

You can simply rinse your water blocks, reservoir and tubing under a tap, and with your radiators you’ll want to heat up some distilled water (or tap water if you don’t have any) and pour it inside. Plug up the holes and shake it well for 30 seconds or so and then empty it. Repeat until no debris comes out with the water. Dry everything off by leaving your parts out for a while or use paper towels.

Step 4: Install the CPU Water Block

First of all, you want to mount the CPU water block which is very similar to installing an aftermarket CPU cooler. Your water block may or may not have come with instructions, but they’re all fairly similar to install.

Before handling any of your components such as your motherboard, don’t forget about static electricity best practices. Either wear an anti-static wrist strap or continually ground yourself throughout the installation process by regularly touching the metal part of your case or another metallic object.

If your water block has a plastic backing for the backplate then go ahead and secure that to the backplate. Then prepare the four corners of your backplate with the corresponding standoff screws and a single washer for each hole. The standoff screws should be the longest screws that came with your block.

Then you’ll have to remove your motherboard so you have better access, and line up each of the four corners of the backplate with the holes on your motherboard that surround your CPU, and add another washer to each screw and then a nut which you should tighten evenly and carefully. Once the backplate is securely fitted it’s time to return the motherboard to its rightful place inside your case (if you prefer) and then mount the block.

Before installing the block you will need to apply thermal paste to the top of your CPU by placing a tiny blob (grain of rice) in the middle and evenly spreading it around the CPU using your finger wrapped up in a bit of plastic or some other means. You can use any paste provided or buy your own such as the high-quality Artic 5 paste which is popular among enthusiasts.

If you’ve had to uninstall an air cooler that was installed onto your CPU, make sure to fully remove any old thermal paste that is left over on your CPU as well.

Now place the water block over your CPU and the backplate screws, and add a washer and a spring to each screw. Use the thumb screws provided to secure each corner evenly by gradually tightening each screw a few twists at a time instead of fully tightening one at a time. You want to apply even, gradual pressure to your CPU and motherboard.

You also want to avoid tightening the block too much; as long as the block is well secured to the CPU and the motherboard, that’s all the pressure you need.

Also, be very careful when installing and/or adding custom parts like this to any PC. Keep a look out for anything that may damage your existing hardware; for example a common potential issue is your mounting hardware screws or washers putting too much pressure on a resistor on the back of your motherboard. Don’t rush anything and be gentle.

Step 5: Install Other Water Blocks 

If you’re not just cooling your CPU and you will be including other components in your loop such as your graphics card or RAM, now is a good time to install the water blocks for those parts.

Step 6: Install the Radiator/s

Your radiator can either mount on the vent your fans usually go, or on the bottom of your case if you have a large enough chassis. If neither of these work for you, you’ll need to install it externally using the brackets that it came with.

Installing the radiator should be fairly simple but will vary slightly in procedure depending on the radiator/s you’re using and your case. Just remember; don’t overtighten the radiator screws as it’s possible they may go right through the fins and create a leak.

Your radiator should come with all the screws necessary, but perhaps not so be prepared with extra mounting hardware like longer screws and more washers if you can.

For the radiator fans you probably want to install them so they blow air from inside the case up through the radiator and out the top of the case.

Step 7: Install the Reservoir

If you’re using a separate reservoir and pump (as opposed to a pump-reservoir combo) then setting up your reservoir first will give you an idea of how the pump will be positioned as well as how the loop will have to be routed to connect to the ports on the reservoir.

A common location to install the reservoir is the spare area in your case where extra HDD brackets would be installed, and you can mount it either using any mounting hardware than came with the reservoir or by using Velcro. If you have a bay reservoir you would simply slide it into a spare drive bay and screw it into place just like when installing a DVD drive.

When using the mounting hardware to install the reservoir, you may already have spare evenly spaced holes in your case to attach the clamps, otherwise you may want to create these holes carefully using a drill (and using a drill bit that is just a fraction larger than your screws).

Step 8: Install the Pump

How you install the pump will vary from model to model, and it may or may not be one of the trickier parts to install. Most pumps will have a single inlet and outlet port and you’ll need to route your tubing in a way that takes this into account.

Some pumps can simply be secured at the base of a 5.25 inch drive bay and held tight with Velcro, others may have a set of tabs that hold the pump in place and can be secured using screws. You could also use a foam pad with double sided tape on both sides. When the time comes don’t forget to connect your pump to a motherboard header or your power supply (you may need an adapter).

Step 9: Connect  Fittings and Tubing

Now that your water block/s, radiator/s, pump and reservoir are all properly in place within your case, it’s time to add the tubing and fittings which connects everything together.

For each connection in your loop, attach the fittings making sure they’re nice and tight before attaching the tubing so as to avoid leaks.

Line up your tubing between the two connection points and cut off the tubing using sharp scissors or a special cutter, and keep a little bit more than you think you’ll need (around 1/2 to a full inch more). Better to have more than you need that you can simply trim off after, rather than cutting it too short. Try to cut the tubing as straight as possible otherwise it may not seal on the fitting properly and could cause a leak.

Do this for all connections, and then start attaching those measured tubes to the fittings, making sure they’re going to the correct fitting. Your block/s, pump and reservoir will have an inlet and outlet labelled. As for the radiator, it doesn’t matter which holes you use.

If you have trouble with fitting the tubing, some needle-nose pliers can come in handy to gently stretch the tubing a little bit so you can more easily install it.

Using swivel fittings can make this process quite a bit easier as they’ll allow you a more flexible range of angles to use.

While installing your tubing you may find that a piece makes too sharp of a turn and creates a kink. This is not good for water flow, and if this occurs you may want to use some longer tubing or rearrange the order of your loop.

Disconnecting tubing from your fittings may be quite hard to do, and in some cases you may even need to cut it off unfortunately.

Pro Tip: If using barb fittings, use zipties or hose clamps to secure them further and make your loop that little bit safer, even if your fittings do indeed feel tight. Tubing can slowly slip off the barbs over time.

Step 10: Prepare Loop for Filling

Now that all the parts of the loop, the tubing, and all the fittings are securely and snugly installed in your PC, do a final check over everything to ensure your loop is ready for that holy water.

Make sure your PC is turned off on both the case and the wall, and make sure to disconnect all the power supply cables. We’ll be using your PSU later to solely test the pump, but we don’t want it to power anything else in your system.

If you’re wondering how to start your pump without your PC powered on (it shouldn’t be!) – you can use a 12V power supply with enough current to run your pump, or you’ll need to jumpstart your power supply using a 24pin jumper (female 24pin with wire running from the green power wire to any of the grounds which tricks the PSU into thinking it’s plugged into your motherboard).

You could also use a paperclip to start your PSU (by bridging the two power points on the PSU) or use a special bridge connector. Some water cooling kits will come with an ATX bridging plug for this purpose. Whatever you do, be careful and make sure you know what you’re doing when it comes to the power supply.

Place paper towel down inside your case in a way that covers your components as best you can. This is to help absorb any small leaks and to more easily spot a leak in the first place.

If you do encounter a leak as you go through the upcoming filling of your loop, and some water gets on your hardware components, relax as there’s a very small chance of damage if you’re using distilled water and there’s no power being drawn to those components.

Simply absorb the leak with paper towel, slowly drain out your loop, fix the leak, and then continue. Using non-conductive coolant also helps to keep your hardware safe but is not necessary.

Make sure that your reservoir is above your pump (height-wise) so that the liquid will flow into the pump via gravity, and attach a fitting and a bit of spare tubing into the fill port on the top of the reservoir.

You might need to use a multi-port top adapter, depending on your reservoir. You might also be able to do without the bit of tubing and simply stick a funnel straight into your reservoir.

You could fill your loop another way such as using a fill bottle, but this method of using spare tubing and a funnel is cheapest and still works well for beginners.

Although there is a potential disadvantage to this method: depending on your reservoir, you may not have a vent port on the top of the reservoir which means the air in the loop being replaced by water has got to exit the same way that the water goes in.

This will cause an air plug, but you can simply try raising the funnel higher or tilt your case around to get around this.

Step 11: Fill the Loop

Carefully pour your coolant in through the reservoir using the funnel until you can’t fit anymore in. When you first fill a loop it will only fill to a certain point backing up into the reservoir.

When that happens it’s time to turn the pump on which will move the water into the rest of the loop and draw water from the reservoir, but before you turn on the power supply and the pump (using whichever method you’ve decided on) you want to “prime” the pump.

Priming the pump means being sure your pump has water in it before you turn it on or continue running it, as using the pump when dry can damage it quickly (literally within a few seconds) as water is its only source of lubricant.

It may be difficult to tell if the pump has water inside or not without actually turning it on, so after turning it on you’ll want to immediately check to see if it starts moving water (you should hear it). If it doesn’t, then turn it off straight away and re-fill the reservoir to continue.

If when re-starting the pump it seems to not move any water at all, shake your case a little form side to side or let gravity work its magic by positioning your case so that the pump is at the bottom of your loop.

So, continue filling your reservoir with coolant and then carefully running the pump (checking immediately that there is water in the pump) until the coolant gets back around to the fill area and can keep going around the loop without extra coolant.

Do so until the air bubbles start to get pushed out; you may need to carefully tip your case left right, back and forth. As bubbles come out your pump should begin to run quieter. Don’t worry if there are few bubbles left as they should go away in time.

Step 12: Test the Loop

You should let your loop run for at least 12 hours, 24 ideally, to check for leaks as they sometimes take a while to be noticed. You want to be confident the loop is working securely before running your PC as normal.

Set up fresh paper towel before you leave your loop to run, and come back every now and then to check if they’re damp at all. You could also keep an eye on the water level in your reservoir; water does evaporate which is natural, but large amounts of missing water could be a sign of a leak.

If there is a leak you will need to drain the loop by disconnecting a tube near the bottom of the loop and draining the water out. Then try to locate the source of the leak; check if any fittings were over-tightened or not tight enough, check the seals in the fittings, and look carefully for any mini cuts in the tubing. Once you find and fix the leak, you can refill the loop.

After you’ve tested the loop for 12-24 hours and you’re happy with operations, it’s time to remove that 24pin jumper from your power supply (or remove whichever temporary power solution you used) and return your PSU to normal operations by plugging all the power connectors back in.

Get your PC up and running properly, and put yourself on the back for completing your very first custom loop! It’s a solid achievement, and you’re now a true PC enthusiast or modder. Or genius. Next step; world domination.

Over the first few weeks of your new water cooling system, occasionally check inside your case for any abnormal water levels, sneaky leaks, and to make sure everything continues to run well.

Step 13: Test Performance

It’s now time to do some monitoring to check your loop is doing its job and nothing is overheating. If a part is overheating, it could mean a badly mounted water block.

When monitoring temperatures of your new water cooling system, remember that the temperatures when your system is idle probably won’t be impressive. It’s only when under load (heavy gaming or when you overclock) that your loop start to work its magic on temps.

A good (and free) program for monitoring your CPU and GPU temperatures (among other features) is NZXT’s CAM.

Maintaining Your Custom Loop

Now let’s get into what you need to know about maintaining your custom water cooling system. This is very basic, especially after having built a loop from scratch.

It’s generally recommended to drain your loop empty and rinse your loop hardware (all water blocks, radiators, and the reservoir) about once every 6 months. You could wait longer and get away with it, such as 9 months to a year, but 6 months is a much better timeframe if you care about looking after your system.

The water in your loop will start to get pretty dirty over time, hence why it’s a good idea to refill with new liquid every now and then. This can also help to keep your loop working optimally and temperatures at their lowest.

If you want to care for your system even more, when you do the routine 6 month (or more frequent) maintenance on your loop you may wish to also replace the tubing with new tubing if it has gotten quite stained.

Wrapping Up

Now that was a doozy of a guide and I hope it's helped in some way on your water cooling quest. If you build a cool rig with this guide then do reach out to me if you want as I'd love to hear about it. We could even feature your build on our site and/or social media if you want.

I'll also be the first to admit I'm no water cooling god so if you're a bit of a veteran and have constructive criticism on how to improve this guide then I'd also love to hear from you. 

At first, building a custom water cooling computer may sound like some farfetched, out-of-reach dream and a topic that belongs in a rocket science class.

But if you do decide it’s worth your time and you actually go ahead and take the plunge 'cause it's a project you've always wanted to do for fun then you’ll find it’s not that complex or difficult.

Thanks for reading and good luck ;)