Water is critical to life. For the whole of documented history, humans have sought clean water for drinking and other uses. According to the 1977 book Drinking Water and Health: Volume 1 from the National Research Council Safe Drinking Water Committee, “The quest for pure water began in prehistoric times. Recorded knowledge of water treatment is found in Sanskrit medical lore and in Egyptian inscriptions. Pictures of apparatus to clarify liquids (both water and wine) have been found on Egyptian walls dating back to the fifteenth century B.C. Boiling of water, the use of wick siphons, filtration through porous vessels, and even filtration with sand and gravel, as means to purify water, are methods that have been prescribed for thousands of years.”

In order to thrive, every society needs to discover or develop an ample supply of potable water, create and maintain a water management system, and transport water to where it is needed. In ancient times, the Minoans on the Greek island of Crete reportedly built the earliest aqueducts. Romans famously used aqueducts to move fresh water to denser settlements. “Roman aqueduct systems were built over a period of about 500 years, from 312 B.C.E. to C.E. 226,” note writers for the National Geographic. “The capital in Rome alone had around 11 aqueduct systems supplying freshwater from sources as far as 57 miles away.”

Responding to Challenges

Thousands of years later, there has been great progress in building and maintaining reliable infrastructures for delivering adequate supplies of clean water to those who need it. Still, cities and regions continue to face challenges. Experts note, for example, that water supplies are never 100% pure. That is why regulations ensure water quality by setting a limit on the amount of harmful substances drinking supplies contain.

Some threats to water quality have been long understood. Others are less well-known. They include per- and polyfluoroalkyl substances (PFAS), which “comprise a large and complex group of synthetic chemicals that have been used in consumer products around the world since about the 1950s,” according to the National Institute of Environmental Health Sciences.

In January 2019, the California State Water Board developed a three-part PFAS Investigation Plan to sample groundwater and soil across the state for potential contamination. That March, in the first phase of this pilot project, samples were taken at airports, municipal solid waste landfills, and drinking water wells within two miles of an airport and within one mile of a landfill. Samples from 600 water systems were taken across the state, which has more than 3,000.

“Across the country the Environmental Protection Agency estimates there are thousands of water systems, serving around 100 million people, that have harmful levels of PFAS in their drinking water,” according to NPR. A 2023 study by the U.S. Geological Survey found PFAS in almost half of America’s tap water. Unsurprisingly, the PFAS Investigation Plan found PFAS in the water supplies for several California cities and counties, including Yorba Linda, which is located southeast of Los Angeles; Santa Clara county, and the City of Pleasanton.

After being notified in late 2019 that the city’s three wells were contaminated, Pleasanton officials quickly informed residents about the issue. They mailed flyers to residents, emailed water customers directly, ensured information was included on utility bills, and held a discussion on PFAS at a city council meeting in November. At the time, the three City of Pleasanton wells contributed about 25% to the city’s water supply. The rest was supplied by the Zone 7 water utility, which also had discovered PFAS in some of its wells.

The Environmental Protection Agency did not establish national limits for PFAS in drinking water until 2024. In 2020, the State of California recommended limits for two common PFAS chemicals. Water providers that exceeded the limits had to stop using contaminated water or notify the public. Pleasanton notified its customers of the issue before it was required by law. The city also stopped using all three of its wells after finding PFAS, although that was not mandated.

Preparing for Future Needs

The residents of Pleasanton, the Tri-Valley, and California as a whole need access to high-quality water. They also need access to an ample supply of water in the face of intermittent droughts, and reliable infrastructure that keeps the water to their faucets flowing. City officials are determined to make sure residents have a worthy, reliable water system that addresses not only contaminants but also water supply and maintenance concerns.

“In 2022 and 2023, it felt like we were trying to play catch up with our water system,” says Heather Tiernan, Communications Manager for the City of Pleasanton. “In 2024, we started to make plans. We know where we're at, we know what we need, and we have a plan to get there.

In late January, a draft of the City of Pleasanton’s first-ever water system management plan (WSMP) was presented to the City Council. Officials say the WSMP, once approved, will be a “living document to guide management of its water system” by defining “near-term and long-term spending and programmatic priorities as a basis for water rate and connection fee requirements.” The initial WSMP focuses on capacity, operational, and rehabilitation and repair needs, and is expected to be reviewed and updated every two and six years.

“The City is now engaging in a plan that is really proactive,” notes Public Works Director Siew-Chin Yeong. “Instead of waiting for a problem with the water service supply or infrastructure, the City is taking a proactive approach to mitigate the situation ahead of time. We are committed to providing clean, reliable, safe water to our residents.”

In early 2023, the City of Pleasanton initiated an alternative water supply study that looked at different options, according to Yeong, who has worked for the city since March 2024. “The council voted to look for new wells. As it turned out, Zone 7 was also interested in new wells to diversify its water supply resources. So we partnered together, and it's a win-win situation for both Zone 7 and us with a cost-sharing approach. The main reason we are doing the Groundwater Wells project is to restore our independence. When we could use all of our wells, we had independent water resources that we controlled. With the regional groundwater project, the City of Pleasanton is guaranteed the first priority and allocation to 3500 acre feet of water from the wells. During difficult times, we can rely on that water.”

The City of Pleasanton invites the public to a Pleasanton Water Open House on Saturday, March 1 from 9 am to 1 pm at the Veterans Memorial Building. Staff will be on hand to discuss how Pleasanton’s water system works, upcoming projects and future needs, and how projects are funded. Tiernan and Yeong encourage residents and business owners to attend to ask any questions they have about the water system.

“We are working to build trust with residents,” Yeong says. “We want them to be confident that we are investing where it is really important. My family is also drinking City of Pleasanton water. We want all of our Pleasanton family to have safe and reliable water.”

For more information about the City of Pleasanton, please visit www.cityofpleasantonca.gov.

For more information about the City of Pleasanton’s water system, please visit www.cityofpleasantonca.gov/our-government/public-works/pleasanton-water.

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