Facilities & Operations FAQ

The Water Authority is capable of delivering more than 900 million gallons per day.  That’s enough water to fill up about 3,000 bathtubs per minute, every minute of the day.

Water is treated and flows through the Twin Oaks Valley Water Treatment Plant.

Historically, approximately 50 percent of purchased water is untreated, and will be treated at one of the treatment plants within San Diego County.  The other 50 percent is treated, and is ready for consumption.


The average cost to treat water in San Diego County is approximately $215 per acre foot.

The pipes that make up the Water Authority’s distribution system range in diameter from 48 to 108 inches, and they traverse approximately 310 miles.

The Water Authority is a gravity flow system, so the actual energy costs to distribute the water are only 2 percent of total energy use. To treat water, the Water Authority spends approximately $7.34/kWh/million gallons.  The majority of energy use goes toward treating, conveying, and storing the water.

Customers should contact the water agency that sends you your water bill. To find out which member agency serves your area, use the handy “locate your water district” search tool on the right of this page.