Swimming Pools

"The typical backyard swimming pool holds 16,000 to 20,000 gallons of water. Pool evaporation amounts to 3 to 7 feet of water per year. For a 15 by 30 foot pool, the range is 10,000 to 23,000 gallons per year for evaporation, plus about 25% to account for splashing. If the pool is filled once a year, it requires about 38,000 gallons of water every year."