The water department learned of the problem only when returning residents reported bad odors and tastes. Hundreds of subsequent water samples found benzene in all of the mains and lines within an advisory area, where residents were warned not to boil or drink tap water. Testing beyond the advisory area in greater Santa Rosa found benzene in some smaller lines, but no water mains.

New Risks to Old Systems

The state’s Division of Drinking Water has said that Santa Rosa’s problem is the first of its kind reported in California. But Horenstein suspects this could have happened in other communities, where smell and odor telltales weren’t as apparent.

Horenstein believes Santa Rosa’s response could have implications for other communities at risk of a similar incident, even nationally.

“I think questions are being raised about prudent use of plastics in a water distribution system,” he says. I think there’s a lot of related questions that will slowly come out of this in terms of industry-wide standards, industry-wide approaches and industry-wide responses to similar problems.”

Even if Santa Rosa’s problem is unusual, other California cities have suffered damages to water systems after significant fire events and related natural disasters. In Santa Barbara County, heavy rains drove a debris flow into the highline distribution water main for the Montecito Water District. Montecito, which is also recovering from major fires, ordered residents to boil water before drinking for about a month in January. Other communities in that area have suffered rock falls and mudslides.

“I think we’re seeing a lot of events both in California and around the country and around the world, where we are experiencing how the change in probability of climate extremes has these indirect effects,” says Stanford climatologist Noah Diffenbaugh. “We’ve made decisions about where to site infrastructure, how to construct infrastructure, based on assumptions about climate that are no longer valid in a statistical sense.”

Diffenbaugh is a member of the Climate-Safe Infrastructure Working Group convened by California Natural Resources Secretary John Laird, which is considering how to better integrate climate considerations into infrastructure design and maintenance. The group will produce a report later this year.

Return to Normal

In Santa Rosa, Horenstein says the city’s goal is to return people to their homes, and return the area to a pre-fire condition. According to a city presentation, the best-case scenario for full replacement in the advisory area would replace the drinking water system over two years.

“It does feel very important for me to assure people, we are going to solve this thing,” Horenstein says.

Santa Rosa could dip into reserves, seek federal aid, or even raise water rates to pay for the full replacement of Fountaingrove’s water delivery system.

And the city may have to weigh that investment against future fire risk: Fountaingrove has now burned twice in the last 54 years.