A water-cooled PC is built by choosing an AIO cooler or custom loop, then installing the radiator, blocks, pump, and lines before leak-testing.
For the full breakdown, see our best Computer Case for Water Cooling guide.
Knowing how to build a water-cooled computer without soaking a new PC comes down to one habit: keep the parts in order and never skip the leak test. Water cooling moves heat from the CPU and GPU into water blocks, then dumps that heat through a radiator and fans.
The project needs a short list of parts and one careful afternoon. Pick a loop style, install in order, fill, and prove the loop is leak-free before powering the rest of the system.
Water-Cooling Your PC: AIO Or Custom Loop?
The first decision sets the difficulty for everything after it. An all-in-one (AIO) liquid cooler ships pre-filled and sealed: mount the radiator, mount the block, connect the pump header, and it is done. A custom loop means assembling a radiator, water block, pump, reservoir, tubing, fittings, coolant, and fans yourself.
AIOs are the simpler path for most builders and handle a modern CPU’s heat without drama. Custom loops earn the extra work when you also want the GPU water-cooled, a specific look, or quieter operation than an AIO can reach. Corsair’s Hydro X Series is a complete custom-loop family built from those exact parts.
Two checks belong before any purchase. The CPU block bracket must match the socket — AM5, AM4, and LGA1700 mounts ship with most current coolers, but verify your exact model and motherboard. The case also has to fit the radiator, and if you are still choosing a chassis, our list of the best computer cases for water cooling shows which ones fit a thick radiator.
Every custom loop shares the same job: blocks pull heat from the chips into coolant, and the radiator and fans push it out of the case. These are the parts you will handle: