Your Drinking Water

Since 1952, Walnut Valley Water District (WVWD) has been committed to providing superior water service to the growing city of Diamond Bar, portions of the cities of Walnut, Industry, Pomona, West Covina, and the easterly unincorporated region of Rowland Heights. The water professionals at WVWD are highly trained and committed to providing reliable, quality water and excellence in customer service.


Aerial view of three large, white, circular storage tanks surrounded by trees and residential houses in a suburban area.

Water Supply

WVWD’s water supply travels hundreds of miles from the Colorado River Aqueduct and Northern California through 434 miles of water pipelines and treatment systems before it reaches a resident’s home. Learn more about our water supply system here.

A man kneels in front of industrial equipment, holding a small clear container with yellow liquid, wearing safety glasses and work clothes in a lab or maintenance setting.

Water Quality & Annual Reporting

Learn about the quality of your water and read the Annual Water Quality Report which is updated in June of each year.

Two large magenta industrial water pumps and valves are installed on a concrete pad in an outdoor utility area.

Recycled Water

WVWD operates a recycled water system to irrigate landscaped areas along freeways, sports fields, parks, medians, school grounds, commercial properties, and community association property. Learn more about our recycled water system here.

A person checks the pressure gauge attached to a green irrigation valve in a garden, with a toolbox nearby on the ground.

Backflow Information

Learn more about backflow prevention devices, theft prevention tips, and testing requirements.