The Presidio is a place where thousands of people live, work, or visit. All these activities require clean, pure drinking water.

The Presidio is part of two watersheds: Lobos Creek Valley to the west and Tennessee Hollow to the east. Mountain Lake and Dragonfly Creek (located near the Native Plant Nursery) are also important ecological resources, though they don’t contribute to the water supply. The Trust is actively protecting the park’s water resources, and conservation is an important part of this strategy.

Lobos Creek and the Water Treatment Plant

A single free-flowing stream, Lobos Creek, meets nearly all the Presidio’s potable water needs. In order to protect the creek’s health and vitality, only about half of the creek’s daily two million gallon flow is used for irrigation, drinking water, and household and employee use. The Presidio Water Treatment Plant draws and treats this water, which is distributed to homes and workplaces throughout the park. Remaining water is purchased from the San Francisco Water Department.

According to the Department of Health Services, the Presidio’s Water Treatment Plant is the second longest continuously operating water treatment plant in California, operating for more than 100 years. The original plant has undergone several modifications and expansions to meet the expanding needs of the Presidio community. View the Presidio’s latest Water Quality Report.

Landscaping, Irrigation, and Infrastructure

• Restoring natural areas with native plants increases valuable habitat and saves water because native plants are adapted to thrive in the Presidio’s climate without additional irrigation. In addition, drought-tolerant plantings are used in many landscaped areas of the park.
• When landscapes are restored, the Trust installs low-flow irrigation systems with sensors and controls to minimize water run-off and waste.
• Bathroom facilities can use 75% of all household water. The Presidio Trust installs low-flow showerheads and toilets in the park's housing units. Water savings from these devices amount to approximately 35,000 gallons per year in a typical three-bedroom/two-bathroom unit.
• A leaky faucet is more that just an annoyance - 2,700 gallons per year can be wasted as a result. Therefore, Presidio Trust preventative maintenance staff inspects plumbing fixtures to keep a drip from becoming a major drain on the water supply.