Bay Area residents need to get serious about meeting Gov. Gavin Newsom’s request in July for Californians to voluntarily cut their water usage by 15%.

The alternative won’t be pretty.

It seems we forgot what the failure to conserve supplies can lead to during a prolonged drought. In 2015, then-Gov. Jerry Brown mandated that urban users across California cut use by 25%, the first in state history. That came a year after the state largely ignored Brown’s request for a 20% voluntary cut in water use.

Now 90% of the state is gripped by extreme or exceptional drought. But residents throughout the state — including Bay Area counties — are largely failing to meet Newsom’s request. As of July, Californians had reduced their home water use by just 1.8%, and Los Angeles, Orange County and San Diego urban water users used more water than they did a year ago.

Marin County residents are paying a heavy price for their failure to conserve water. The county declared a water-shortage emergency on April 20. Forecasts show the area could deplete its main reservoir supplies by next summer should the region experience a third consecutive dry winter this year. Residents in rural areas are having to truck in supplies from as far away as Sacramento County, and the Marin Municipal Water District set a 40% conservation goal in April.

Santa Clara County residents are starting to feel the pinch of dwindling supplies, as well. The San Jose Water Company, which serves 1 million people in San Jose, Campbell, Cupertino, Los Gatos, Saratoga and Monte Sereno, is issuing notices to residents of mandatory rules for conservation that will include financial penalties for homeowners who exceed the targets. Residential customers who fail to cut use 15% from 2019 levels will pay $7.13 in surcharges for each unit (approximately 748 gallons) of water they use above that amount. The county’s 10 reservoirs are just 11% full as of Thursday. And the county’s largest reservoir, Anderson, had to be drained last year after federal officials ordered the dam had to be rebuilt to meet seismic standards.

The Mid-Peninsula Water District is asking San Mateo County customers to voluntarily reduce water consumption by 10%.

In the East Bay, the Contra Costa Water District has called a stage 1 water shortage and is asking customers to voluntarily cut water use by 10%. The East Bay Municipal Utility District is also asking customers to voluntarily conserve 10% of water usage and has imposed outdoor watering rules that call for residents to water their lawns one less day per week than usual. Alameda County is asking customers to conserve but has no mandatory water restrictions in place.

Those are shortsighted approaches that will cost residents dearly if the drought persists into 2022 and beyond. Every water agency and user must do their part to use the minimum amount of water until this drought ends.

The California Water Resources Control Board in August took unprecedented action by barring thousands of California farmers with senior water rights from diverting water from rivers and streams. It’s an acknowledgment that climate change is forcing the state to cut water supplies for anything that doesn’t constitute essential use. Bay Area residents need to acknowledge the urgency of doing everything possible to reduce their water consumption before reservoirs demand further emergency measures.