OCWD is a leader in water and natural resource management, carrying out award-winning environmental programs that also provide water supply benefits. OCWD manages the largest constructed wetlands on the west coast of the United States in the Prado Basin to naturally remove nitrates from Santa Ana River flows. Natural resource conservation programs conducted by OCWD have brought back an endangered California songbird, the least Bell's vireo and have helped a threatened bird, the Southwestern Willow Flycatcher.

OCWD developed a program to remove a water-guzzling, invasive grass called Arundo donax from the watershed. Removing this non-native grass and replanting with native plants not only restores a more water-efficient, natural habitat but also conserves precious water supplies.

Additional environmental programs include restoration work supporting the endangered Santa Ana Sucker fish and breeding bird territories.

Sucker Fish. OCWD designed and implemented, in partnership with many other agencies that include the Santa Ana Watershed Association (SAWA), the only currently successful sucker habitat restoration project on the Santa Ana River.

In 2005, Sunnyslope Creek, a small tributary to the river located near Mt. Rubidoux in Riverside, closed off to the river when it relocated in high flows. Prior to that, the creek was one of few known spawning sites for the threatened sucker fish. The OCWD crew conducted studies and began managing the creek in 2010 to keep it hydrologically connected to the river and as free of big, non-native predatory aquatic species as possible. The project continues today and was deemed a success beginning in 2011 when suckers in spawning condition were again detected in the creek.

Breeding Bird Territories. A result of restoration funded by the Burris Basin Reconfiguration Project, there is a productive 1.5 mile-long riparian strip along the entire edge of the Prado Basin that supported over 150 breeding bird territories in 2014 of 51 different species including Song Sparrows, hummingbirds, swallows, California Towhees, House Finches, Lesser Goldfinches, Mourning Doves, Northern Mockingbirds, Bushtits, Scrub Jay, Yellow Warbler, Common Yellowthroat, Ash-throated Flycatcher, and Black Phoebe.

On the nesting bird island there were 18 nesting attempts by California Least Terns, most of them successful along with Forester's Terns (210 nests, 457 eggs laid), Black Skimmers (91 nests, 228 eggs), American Avocets (58 nests, 184 eggs), Black-necked Stilt (28 nests), Killdeer (22 nests), Spotted Sandpiper (3 nests), Mallard and Gadwall (17 nests, 179 eggs), and Canada Goose (5 nests, 24 eggs), among others.

OCWD has a reputation of providing clean, fresh water to more than 2.4 million ratepayers in north and central Orange County. The story of its responsible environmental stewardship is only beginning to be told.