With rural wells at risk of drying up, Marin County is seeking to puchase emergency drinking water to supply a small group of households in West Marin. 

On Tuesday, Marin Water and North Marin Water District passed resolutions that will allow the county to sell their water to these homes if the private wells on the properties run dry. 

County officials identified between 10 and 30 homes in the Nicasio, Lucas Valley and Marshall areas that could be vulnerable because they rely on wells and are outside of the regular service areas. 

Residents will cover the cost of the water, and the county will help secure state grants for those who can’t afford to pay for the trucking or the necessary supplies, like water reserve tanks.

Many of these residents would ordinarily truck in water from Marin Water or N.M.W.D. during the dry summer months, but both providers barred out-of-district delivery as drought conditions worsened. The cost of a truckload of water from elsewhere in the state has risen dramatically since the drought, becoming prohibitive for many. 

“The whole picture told me that maybe the county needs to step up into the role here,” said Supervisor Dennis Rodoni, who initiated the emergency program. “We’re just trying to keep everyone somewhat afloat in this drought.” 

The program marks the first-ever effort by the county to buy water from providers and distribute it according to need. 

Lack of water is a public health issue, said Dr. Lisa Santora, the county’s deputy public health officer. “When you have a low well supply, you would potentially have a concern about the quality of that water,” Dr. Santora said. She stressed the urgent need for hydration on the hot, dry days that are becoming more common in Marin. 

The utilities would need to provide enough for the state-recommended 55 daily gallons per person, amounting to less than one acre-foot of stored water over a four-month period. The county, not the individual homeowners, will be the districts’ customer in this case, but the residents are still required to conserve as much water as in-district customers. 

Customers will need to prove that they have no alternate source of water, and they will only be allowed to use the water for indoor purposes. 

Marin Water will supply the households in Nicasio and Lucas Valley with water from a metered hydrant in San Geronimo that draws from the district’s seven reservoirs. The emergency use would only add up to about a .02 percent of the district’s total water usage, said spokeswoman Emma Detwiler.

Last month, the district became the latest in Marin to announce penalties for high water use. The restrictions, which allow for 65 daily gallons per person, will kick in on Dec. 1 regardless of usage, and come with a complex tiered penalty system.

North Marin serves Novato along with Point Reyes Station, Olema and Inverness Park in its regular service area, and the county would likely use N.M.W.D. water only for the Marshall customers, said Tony Williams, the district’s chief engineer. At under 1 percent of the district’s total usage, “it’s almost immeasurable compared to what we’re supplying our other customers,” he said. “Despite having such low supplies, we’re willing to participate given that small increment.”

Although North Marin’s Coast Guard wells are closer to Marshall, the district plans to supply the emergency customers through a hydrant in Novato. The county already has an account to use the hydrant on San Antonio Road to supply emergency water to ranchers in West Marin. The hydrant water, which is sourced mainly from the Russian River watershed in Sonoma County, is more plentiful than the Coast Guard water, even with a 20 percent allotment reduction from Sonoma Water. 

North Marin is also concerned about salinity levels at the Coast Guard wells. “We just don’t want to exacerbate that problem,” Mr. Williams said. “We think we have that under control and the last thing we’d want is to suddenly have more demand on the system.”

This week, the district measured levels of sodium that ranged up to 149 milligrams per liter, exceeding the 115-milligram-per-liter limit that represents 10 percent of the recommended daily sodium intake. As a result, the district will now provide treated water from another West Marin well to customers on low-salt diets at bottle filling stations at the Coast Guard property. Customers don’t need to show any proof from a doctor, and can fill up containers on Tuesdays from 1:30 to 4:30 p.m. and Fridays from 9 a.m. to 1 p.m. 

The low-salinity water is not intended for well users, and Mr. Williams said anyone with concerns about their well should refer to the county’s emergency program. 

In rural West Marin, some residents have long contended with salty or unsafe well water, but because they live in unpermitted housing, accessing water formally through utility districts or the county poses a challenge. Instead, West Marin Community Services provides free bottled drinking water, and the nonprofit is careful not to expose them to scrutiny that could lose them their housing or jobs. 

“We have the funding to provide water, and when people come, we don’t ask questions,” said Socorro Romo, the nonprofit’s executive director. 

Agricultural operations have also suffered. North Marin Water District previously used its hydrant on San Antonio Road strictly as a fire hydrant, but in June, it gave approval to the county agricultural commissioner’s office to tap it for West Marin’s ranching operations. Marin Water also began serving agricultural operations starting in late spring. 

County agricultural commissioner Stefan Parnay said the amount of water drawn by the roughly 30 producers is a small fraction of the district’s total usage, comparable to the amount that evaporates from the surface of the reservoirs each month. Since the county authorized the draws in June, ranchers have taken about 11 acre-feet from the hydrant, the same amount from Marin Water’s Nicasio Reservoir, and an additional 1,800 gallons per day from Stafford Lake. 

After the emergency agricultural use was authorized, a few residential property owners in West Marin alerted Supervisor Rodoni that their wells were at risk of running low. 

Last month, the supervisor facilitated a special meeting with the water districts and county staff from the Office of Emergency Services and Department of Health and Human Services to begin to address the needs of these rural homes. 

County officials don’t know exactly how many households may need emergency water, though they estimate the number won’t exceed 30. For the moment, their assessment mostly stems from the constituents that already approached Supervisor Rodoni with their concerns. Dr. Santora said the county will partner with community organizations like the Nicasio Landowners Association to identify other potentially vulnerable properties.