Sometimes called "tap" or "refill" water. It is the water used to replace water lost to evaporation, splash out, leaks or swimmer drag out in the pool.

fresh water used to fill or "top-up" a pool or spa. Oftentimes referred to as "source water".

Fresh water used to fill or refill a swimming pool.

Also called top up or refill water. It is the water used to replace water lost to evaporation, splash-out, leaks and backwashing.

Water added to a tank, boiler, or other vessel to maintain a pre-determined liquid level.

Water that replaces the water lost through evaporation or leakage, such as in a steam heating system.