2025 Water Quality Report

Providing safe, clean water — day in and day out

IRVINE RANCH WATER DISTRICT WATER SOURCES Where does your water come from? IRWD water comes from local groundwater, recycled water, local surface water (rainwater capture), and from imported water from Northern California and the Colorado River. Recycled water is not used for drinking but is an important water source that reduces demand for drinking water.

RAINWATER CAPTURE

Shasta Lake

Irvine Lake

ORANGE COUNTY

Lake Oroville

SACRAMENTO- SAN JOAQUIN RIVER DELTA

Rattlesnake Reservoir

SACRAMENTO

Groundwater Well Field

Mono Lake

Syphon Reservoir

SAN FRANCISCO

FOOTHILL RANCH

Groundwater Well Field

LOS ANGELES AQUEDUCT

Michelson Water Recycling Plant

LAKE FOREST

STATE WATER PROJECT (imported water)

IRVINE

Baker Water Treatment Plant

Los Alisos Water Recycling Plant

GROUNDWATER BANKING

Sand Canyon Reservoir

COLORADO RIVER AQUEDUCT (imported water)

NEWPORT BEACH

San Joaquin Reservoir

LOS ANGELES

Local Groundwater Drinking Water Treatment Plants Recycled Water Treatment Plants Recycled Water Reservoirs

Lake Mathews

LOCAL GROUNDWATER

IRWD SERVICE AREA MAP

PACIFIC OCEAN

ORANGE COUNTY IRWD SERVICE AREA

SAN DIEGO

Diversity of supply IRWD has carefully diversified its water supply and is not dependent upon only one source of water. Your drinking water is a blend of local groundwater, groundwater from the Orange County Groundwater Basin managed by the Orange County Water District

In managing these various water sources, IRWD will sometimes switch water sources or blend them based on availability, treatment needs, time of the year, assisting other partner agencies and local geography.

Recycled water is another important water source. While not used for drinking, it significantly reduces demand for drinking water. IRWD has been recycling highly treated wastewater since 1967, and it’s now used to irrigate landscaping, flush toilets in large commercial buildings

(OCWD), and to a lesser degree surface water imported by Metropolitan Water District of Southern California (MWD), which comes from the State Water

Project and the Colorado River Aqueduct. IRWD also has a local watershed that feeds rainwater to Irvine Lake, which IRWD uses as a surface water source. Local water sources keep the costs lower for our customers and significantly increases the overall reliability and resiliency of your water supply.

and even used in some industrial equipment like cooling towers. Using recycled water for these purposes is important because every gallon of recycled water saves a gallon of high-quality drinking water for you, our customers .

IRWD's Baker Water Treatment Plant in Lake Forest produces enough water to serve 63,300 homes and provides an additional source of reliable, high-quality drinking water.

IRWD Water Quality Report 2025 | Page 3

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