The Sierra Mountains may be low on snow this winter, but San Francisco’s Sierra water source is far from running dry.

The Hetch Hetchy Reservoir, the utility system’s primary source of drinking water, is at 85 percent of its capacity, according to the San Francisco Public Utilities Commission.

Tuesday, the California Department of Water Resources announced that the January snowpack for the Sierra Nevada is lower than it has been in decades, at just 19 percent.

“The low snowpack numbers also remind us about the importance of maximizing every drop of water,” Commission General Manager Ed Harrington said in a statement. “Wise water use always starts first with conservation.”

The system’s reservoirs are relatively full, despite this season’s dry weather, because of last year’s wet weather, Harrington said.

Peninsula and Alameda watershed reservoirs, including Crystal Springs, Andreas Lake, Pilarcitos and San Antonio reservoirs, are filled to about 79 percent their combined capacity.