PLEASANTON — A costly project to replace drinking water wells closed because of contamination is moving forward as the issue of drinking water quality tops the city’s election campaign agenda.

Five years ago, the city of Pleasanton began shutting down its underground water system. Eventually, three wells were shut down and an estimated 22,000 customers were transferred to a water wholesaler that serves eastern Alameda County. Now officials are looking for new wells, a project estimated to cost between $23 million and $43 million.

The issue has become one of the hottest topics among candidates running for seats in November, including the head-to-head race between current Mayor Karla Brown and City Councilman Jack Balch.

When the city discovered perfluoroalkyl and polyfluoroalkyl substances in 2019 – substances commonly found in Teflon or “non-stick” chemicals known as PFAs – “it was a surprise to all of us,” Brown said in an interview.

“In 2019, we had never tested for it before,” she said. “In my role as mayor of Pleasanton, the most important decisions I make are protecting the health of our citizens.”

“The long-term water supply for the Tri-Valley and Pleasanton in particular is extremely important,” Balch said. “Water is obviously essential to life, it’s essential to our economy. And it also needs to be affordable and available in our economy.”

The city is currently in the planning and exploration phase of the three-phase project and plans to test several sites for possible well drilling by the end of this year, probably for four to eight weeks sometime between October and December, according to city spokeswoman Heather Tiernan. After that, the city will also decide on the possibility of building a water treatment plant to siphon off dangerous pollutants and chemicals in-house.

The planning and construction phase of the project won’t take place for several years, officials said. An update on the status of the new fountain project is expected next spring, Tiernan said. City officials have not yet decided how to finance the entire project and have so far committed only $1 million to cover planning and development costs.

Over the years, Pleasanton has purchased most of its drinking water – about 80% – from the Livermore-based Zone 7 Water Agency, which will cover the million-dollar planning and development costs for this new project. The remaining 20% ​​was supplied from the city’s groundwater wells until 2019.

The city initially closed one of three wells because the contamination was so severe that the city had to notify residents about chemicals in the water. In 2022, two more wells were closed, cutting off 3,500 acre-feet of water supply. Eventually, the city switched to referring its customers in the affected area to Zone 7, the regional water wholesaler based in Livermore.

Authorities claimed the contamination was not so severe that it was toxic or life-threatening, but Tiernan said it was enough to shut down the wells out of an “abundance of caution.”

During a dry spell last year, the city considered the possibility of tapping its wells again to meet increased demand, but Tiernan said the city “no longer uses them to provide water to our community, and we don’t plan to.” The rainy and winter seasons of recent years provided enough water to replenish the city’s reserves, and there is no longer any immediate or planned demand for the contaminated water.

Mayor Brown believes that the discovery of a new well will reduce water prices for the population, as it is cheaper to supply the city with its own water than to get it from elsewhere, for example from Zone 7.

The source of the contamination is still under investigation, Brown said, and it is unclear where the contamination came from.

“As we seek additional well water resources, the health of our citizens once again becomes the most important variable,” Brown said. She added that “every elected citizen should make this their top priority: clean, safe drinking water.”

Balch, meanwhile, said residents are currently experiencing issues with water hardness, or the mineral content of the water coming out of their taps. Balch said, “We’re talking about what’s critical and vital, but if you don’t have access to clean drinking water, that’s a real life issue.”

“I think we obviously have to proceed with caution given the size of the investment,” Balch said. “(And) make sure the plan produces sufficient water in sufficient quantity and quality.”