SANTA ANA, Calif. (AP) — Thirty-seven water districts or cities around California have passed rules restricting the use of water in swimming pools in the past few months due to a devastating drought. The new regulations range from mandating the use of pool covers to reduce evaporation to outright bans on filling or refilling new or newly drained pools to requiring that pool owners fill up with water from an external source that won't reduce the supply of drinking water.
Here is a look at some of the water facts related to swimming pools that have water agencies on edge.
DROPS IN A BUCKET: The average backyard swimming pool ranges from 10,000 to 30,000 gallons. The largest Olympic-sized commercial pools hold 660,000 gallons — what the typical American family uses in a year, according to the U.S. Environmental Protection Agency.
EVAPORATION EQUATION: Swimming pools left uncovered can lose up to an inch of water a week due to evaporation. That rate can vary widely, though, depending on the outside temperature, humidity levels and wind. Some pools in the hottest, driest areas such as Las Vegas can lose up to four inches a day to evaporation in the summer months.
PLEASE COVER UP: In California, only 30 percent of pool owners use covers regularly despite studies that show covers can reduce evaporation by up to 90 percent in some cases and reduce the demand for topping off the pool by 30 to 50 percent.