The biggest concern people often have with building a custom loop: will it leak? It’s a valid concern. We were taught from a young age that water and electricity don’t mix, presumably so that we wouldn’t try and make toast while having a bath. But liquid cooling is special—we go against old beliefs for performance, silence and aesthetics.
I’m not going to lie to you; you’re building a system that pumps water through connections that you have assembled yourself. There are risks and leaking is one of them but just not as likely as you might think.
In the four years since I first discovered the joys of custom water cooling, I’ve had just one leak and it was entirely my own fault. A certain brand of radiator was known for cracked channels in the end plates. Instead of testing it prior to installing, I rushed through the final stages of my project and ended up with an orange pool in the bottom of my case. Had I done things the right way this wouldn’t have been the case.
This brings me to the most important rule of water cooling: take your time and double check everything. You want your fittings to be secure but not overtightened and you want to make sure any unused ports are secured with stop fittings. The last thing you want is to fill your reservoir only for it to immediately pour out through the drain port, making a mess, or worse, ruining your expensive parts. Carefully plan your loop in a way that mitigates potential damage that a leak could cause. For example, don’t mount your reservoir directly above your motherboard or power supply.
Leak testing is also very important. Always ensure that when doing so, either bridge your power supply with only the pump connected, or use an external supply to power the pump while checking for leaks. Unless you like buying things twice, never power any components while checking for leaks. If water hits an unpowered motherboard, it will dry and remain functional.
Many people recommend leak testing for a full 24 hours; However, I’ve found that when things go wrong, it typically happens almost immediately. At the very least, test for a couple of hours which you will need anyway to allow any air bubbles to escape.
If you follow these very simple rules water cooling can be a very fun and safe hobby. The performance benefits aren’t as great as they once were but they are still evident and the knowledge gained from putting together your first loop is invaluable.
Finally, if you're still too concerned and decide that building a custom loop isn't for you but you still want to have a liquid cooled PC, you can opt for an all-in-one loop. Coolers such as the NZXT Kraken or Corsair Hydro series coolers do a fantastic job at reducing temperatures and come pre-filled and sealed from the factory.