Is it sustainable for Sonoma County to build new homes during an ongoing water crisis?

Starting in 2023, the state wants Sonoma County to approve over 14,500 new homes for residents of all income levels over the following eight years.

Though no final target has been approved, officials in some of the county’s largest cities have made ramping up home construction a priority with the goal of alleviating the region’s shortage of affordable housing.

At the same time, though, the state is also mandating water cutbacks across the region during what is shaping up to be the worst local drought in more than four decades.

The two seemingly competing mandates have some questioning the wisdom of continuing to push growth in the face of a water crisis.

“How are we still approving new development in the midst of a two-year drought with no idea what's going to happen next year?” said David Keller, a Petaluma resident and Bay Area director of Friends of Eel River, a Eureka-based environmental advocacy group.

Sonoma County residents posed similar questions to The Press Democrat as part of its North Bay Q&A series, which collects and answers readers’ questions about life in the region.

Municipal planners and local officials answer that they’ve carefully considered the area’s expected water supply over the next few decades and are confident it will be enough to meet demand, even when sustained dry years are taken into account.

They contend that conservation efforts, which have significantly reduced per-person consumption, will help ensure that the region’s reservoirs, wells and underground aquifers can provide the necessary water even as more people move to the area.

“Ongoing conservation has just overwhelmed population growth, and our overall water consumption continues on a steady downward trend,” said Petaluma City Councilman Mike Healy, a former chair of the advisory committee to Sonoma Water, the region’s primary water management agency.

That doesn’t change the fact that Lake Sonoma and Lake Mendocino — local cities’ main water sources via the Russian River — are currently approaching record lows. As a result, the state ordered water cutbacks, pushing most of the county’s cities to issue mandatory water reductions of between 20% and 40%.

In light of the severe shortages, conservationists are skeptical of officials’ projections about future water supplies. They argue the state and local municipalities should reconsider whether the region’s water systems can support substantially more homes.

Rue Furch, an environmental advocate and former member of the Sonoma County Planning Commission, said there are many unknowns about the region’s water supply beyond just the impacts of climate change. That includes exactly how much is held in the county’s groundwater reserves and who will eventually take over the aging PG&E-owned Potter Valley Project, which diverts billions of gallons of water each year from the Eel River to Lake Mendocino.

“While jurisdictions are being really mindful of water use, the uncertainty of water availability makes it hard to definitively say, ‘of course we can build more,’” she said.

Local officials say they are confident the county’s water supplies can support continued growth. Under state law, all urban water suppliers are required to create detailed management plans every five years to outline how current and future water demands will be met.

The county’s three largest cities — Santa Rosa, Petaluma and Rohnert Park — each create their own plans to determine how much water they need for at least the next 20 years. The documents must take into account climate change, expected population growth and housing development, among other factors.

Sonoma Water in turn uses those plans to create its own water management plan for urban areas in the region. By 2045, annual demand from the agency’s eight water contractors in Sonoma and Marin counties is estimated to reach more than 24 billion gallons of water, a 41% increase from 2020.

Paul Piazza, a Sonoma Water manager who helped draft the agency’s most recent plan, said currently available water resources should be enough to cover that increase under most future environmental conditions.

To predict the impact of climate change on the long-term water supplies, the agency collaborates with researchers from the National Oceanic and Atmospheric Administration and scientific nonprofits, Piazza said. He added that if extreme drought scenarios are found to be more likely, Sonoma Water will update its plan and work to identify additional water supplies.

“This is an exercise that we revisit on a five-year cycle because of the fact that things change,” Piazza said.

In those plans, Sonoma Water and local water suppliers also have to take into account the state-mandated housing goals. The new construction targets are currently being updated in some local water management plans, which could increase the region’s total projected water demand.

Between 2023 and 2031, the county’s three largest cities will together likely be required to permit about 7,500 new housing units, a 10% increase over the current eight-year housing cycle. The target for unincorporated Sonoma County, which accounts for about a third of the county population, is for now set at almost 3,900 new units, a more than 650% jump.

In response, the county last month appealed to have that figure cut in half, in part due to a lack of sewer and water infrastructure as well as drought concerns.

Dave Vautin, an assistant director Association of Bay Area Governments, the agency in charge of divvying up the state’s housing goals among the region’s cities and counties, said it took into account water supplies and infrastructure in making housing allocations.

Vautin said the agency will carefully review the appeal, but rejected the notion that the Bay Area should build fewer homes because of water concerns.

“Building less housing in the nine-county region could simply shift responsibility to address this key policy issue to neighboring counties or states,” he said in an email.

Local governments who don’t adequately plan to meet those goals can face fines, miss out on state housing grants and lose land-use authority over proposed residential projects.

Rohnert Park City Manager Darrin Jenkins, stressed the need for more housing in the county, especially as an influx of Bay Area residents have pushed single-family home prices to record highs, and driven up rent prices as well.

Jenkins doesn’t expect water shortages to get in the way of meeting Rohnert Park’s housing mandate, though he does have concerns about securing sufficient private financing for new projects. His confidence about the city’s water supply is in large part due to its longstanding conservation efforts, Jenkins said, including installing water meters at homes, updating plumbing codes and offering rebates for water-efficient appliances.

“We’ve done a lot of work to reduce our consumption of potable water. In fact, we’ve cut it in half since 1997 on a per-person basis,” he said, noting demand dropped from 179 gallons to 90 gallons a day.

But going forward, local officials have noted that since Sonoma County residents have become more water conscious, there remain fewer ways to continue curtailing their consumption — a concept known as demand hardening.

“As people take the easy conservation steps, it’s harder for them to do more because they’ve already done the easy stuff,” said Healy, the Petaluma councilman.

Larry Florin, chief executive of Burbank Housing, said the affordable housing developer has embraced water efficiency in its projects by incorporating low-flush toilets, on-demand water heaters and drought-resistant landscaping.

“That’s really the future and that should be mandated,” Florin said. “We’re completely comfortable with mandated low water usage. It’s the reality and we think it’s smart.”

He added that uncertain water supplies have not as of yet raised serious concerns for Burbank Housing’s developments, but said one potential Napa County project in St. Helena could be delayed due to restrictions on new water hookups during the drought.

Santa Rosa, like other local cities, also has contingency plans for projects seeking hookups during a water emergency. So far, those plans have yet to be activated.

But if current drought conditions worsen, the city could require developers to offset a new building’s water footprint by paying for water conservation projects elsewhere in the city, such as replacing the grass at a high school football field with artificial turf, city officials said.

“Let's look ahead and really think about the worst case scenario,” said Peter Martin, deputy director of water resources with the city. “That's where we're at right now.”

Laura Feinstein, an environmental policy expert at Bay Area think tank SPUR, stressed the need for denser housing, such as apartments and townhomes, which tend to have shared yards and use much less water than single-family homes.

Feinstein acknowledged that some residents in cities may chafe at being told to sacrifice their water use as the local wine, cannabis and agriculture industries draw significant amounts of the region’s water supplies. While it’s unclear exactly how much those industries consume locally, some researchers estimate around 80% of the state’s water use is tied to agriculture, she said.

During the drought, North Bay farmers, vineyards and other agricultural water rights holders have seen their allotments slashed by the state or are facing dire shortages.

To help both urban and rural water users conserve into the future, Feinstein highlighted recycled water, rainwater capture, underground water storage and water transfers between municipalities as potential innovations.

But she was quick to point out they would all cost money.

“You're essentially asking the people who live in Sonoma County to invest in their water system so they can continue to accommodate the people who want to live in that area,” Feinstein said. “If the answer to that is yes, then we have the tools at our disposal to make sure we have enough water to go around.”

You can reach Staff Writer Ethan Varian at ethan.varian@pressdemocrat.com or 707-521-5412. On Twitter @ethanvarian.