Do I need water cooling to mine on a CPU?

No, water cooling is not required to mine Malairte on a CPU. A quality dual-tower air cooler from a known brand will keep modern Ryzen and Intel CPUs comfortably below their thermal limits even under sustained mining loads. Air coolers have one major advantage for 24/7 mining: they have no pump, no coolant, and no risk of a leak onto the GPU sitting underneath. All-in-one liquid coolers do have their place, especially for higher-end CPUs in cases with poor top clearance, but they introduce a wear component (the pump) that will likely need replacing every three to four years under continuous load. For a typical home mining build with a six- or eight-core CPU, spend your money on a generous air cooler rather than an AIO. It will be quieter, simpler, and more reliable over the long run.