What we do
As a public agency, OCWD takes on the water challenges of today and prepares to meet the region's water demands for generations to come.
OCWD manages three of Southern California’s greatest water supplies: the Santa Ana River, the Orange County Groundwater Basin and the Groundwater Replenishment System (GWRS). It ensures a reliable supply of high quality water for more than 2.5 million residents in north and central Orange County, while protecting environmental habitats and natural resources.
The largest river in Southern California, the Santa Ana River begins in the San Bernardino Mountains and flows downstream to Prado Dam and on to the Pacific Ocean. OCWD owns and manages a 6-mile (9.7 kilometers) stretch of the river. River flows are affected by water use upstream and weather fluctuation, making them less reliable than other water supplies.
One of the largest of several coastal basins in Southern California, the Orange County Groundwater Basin contains approximately 500,000 acre-feet (162.9 billion U.S. gallons; 616.7 million cubic meters) of usable storage water and covers 270 square miles (69,930 hectares; 699.3 square kilometers). The underground basin is millions of years old and is 4,000 feet (1.2 kilometers) at its deepest point. Managed properly, the basin is a reliable source of water.
The GWRS is the world’s largest advanced water purification system for potable reuse. A joint project between OCWD and the Orange County Sanitation District, it provides water supplies that are added to the Orange County Groundwater Basin. GWRS water is also injected into coastal barrier wells to keep seawater out of the basin. GWRS water is highly reliable, even during times of drought.