noun, noun which may take the genitive case particle 'no'
warm water
Refers to water that is warm, not hot. Commonly used in contexts like heating, bathing, or swimming pools.
温水プールで泳ぐのが好きです。
I like swimming in a heated pool.
温水
I washed the vegetables with warm water.
Mix warm water and cold water to get the right temperature.
このホテルの部屋はすぐに温水が出る。
Warm water comes out right away in this hotel room.
I soothed my tired feet by soaking them in warm water.
This equipment supplies warm water to each floor.
冷水 is cold water, the direct opposite of 温水, which is warm water.
water heater; calorifier
hot water tank
heated swimming pool
bidet toilet seat with warm water; warm-water washlet
Compound of 温 (warm) and 水 (water). The reading is on'yomi for both characters.