How clean is Silicon Valley’s drinking water?

It’s been more than two decades since the movie “Erin Brockovich” brought the real-life issue of contaminated drinking water in a small Southern California town to a mass audience.

But the harmful compound at the heart of the film, Chromium-6, is still present in much of the drinking water around the state, including in the South Bay.

State water officials are about one year away from possibly enacting a new standard to limit how much Chromium-6 is allowed in drinking water, a purity standard that many South Bay water agencies already meet. Some advocates say the proposed rules don’t go far enough to protect public health, while state water officials say the regulations must also consider the higher costs some water agencies and consumers would face if standards become more stringent.

“There is an economic part of the problem that has to be dealt with, but on the other hand what is the economic cost of people getting cancer?” Bill Allayaud, a lobbyist with Environmental Working Group, told San José Spotlight. Environmental Working Group is a nonprofit that advocates for stricter standards on harmful compounds in water, agriculture and other consumer goods. It created a map where consumers can view information about what’s in their local water supply.

Chromium-6, also known as hexavalent chromium, is an odorless and tasteless heavy metal, which studies link to cancer risk for people with long-term exposures to it through drinking water, according to state reports. The metal occurs naturally in parts of California’s groundwater and soil, though more can leach into water supplies through industrial contamination, such as what happened in the town of Hinkley, depicted in the film “Erin Brockovich.”

In Hinkley, PG&E long used the metal to protect some of its equipment at a pumping station in the town, and later allowed the chemical to seep into the water supply. Town residents, including children, fell ill because of PG&E’s actions, and Brockovich helped residents win a $333 million settlement from the utility company.

“It’s not good to drink a toxic carcinogenic agent in any concentration,” Max Costa, environmental medicine department chair at the NYU Grossman School of Medicine, told San José Spotlight.

Costa was the lead expert witness in the Brockovich trial, offering his opinions on how harmful Chromium-6 could be to residents drinking it in high concentrations.

“If it’s very low, you don’t need to worry about it too much,” Costa said.

Tighter regulation on the way

While current state standards limit chromium in drinking water to 50 parts per billion, that measurement can include other kinds of chromium such as Chromium-3, which is considered a beneficial nutrient. The 32-year-old federal standard is 100 parts per billion of total chromium.

The new proposed California standard, which will be considered by the State Water Resources Control Board likely in 2024, would specifically focus on Chromium-6 and limit it to 10 parts per billion. An equivalent measure would be roughly 10 cents out of $10,000,000, or 10 minutes out of 1,900 years, according to San Jose Water Company, one of the water suppliers in the city. The state passed a regulation with the same limit in 2014, but it was later repealed in 2017 after a lawsuit brought in part by manufacturing groups.

Darrin Polhemus, deputy director of the State Water Board’s Division of Drinking Water, said the cancer risk for someone who drinks water with 10 parts per billion of Chromium-6 regularly for 70 years is roughly one in 2,000.

“As the regulator in charge, I would much rather be at a lower health protective number than 10, but 10, factoring in the treatability and the cost associated with that, is definitely a compromise position,” Polhemus told San José Spotlight. “I don’t find it satisfying, but it’s kind of where we come out on that.”

Local water agencies not affected

According to the most recent water quality reports from Valley Water, which provides water to roughly two million people in Santa Clara County, Chromium-6 is is below one part per billion, and therefore considered not detected.

But as water retailers mix in other sources of water with what they get from Valley Water, Chromium levels can vary. San Jose Water, which provides water to roughly 1 million people, shows in its quality reports that Chromium-6 levels average 2.6 parts per billion for customers served by groundwater sources, but range as high as 4.5 parts per billion. Other sources they use show it as low enough to be considered not detected.

Santa Clara’s customers served by well water sources range from less than 1 part per billion up to 4.1 parts, the city’s water quality reports show. Other places in the state see much higher levels of Chromium-6, such as in Coachella Valley, where levels range from under 1 part per billion up to 23 parts, depending on the source of the water.

Vanessa De La Piedra, head of groundwater management at Valley Water, said most South Bay water customers likely won’t be affected by the proposed rule change. She drinks tap water at home or water run through her fridge’s filter, and said if people have concerns about the quality of their water, they should talk to their water provider.

“The water provider really is the one to be able to speak to their specific sources of supply, the testing that has been done and what they see,” De La Piedra told San José Spotlight. “Public water systems go through extensive testing and extensive monitoring.”

A state department tasked with evaluating how much of the metal would limit cancer risk to one in a million people over a 70-year period recommended Chromium-6 levels be reduced to 0.02 parts per billion in drinking water.

But regulators must consider the costs and feasibility for water agencies to meet the requirements.

“We want to be as healthy as possible, but we do need to keep it economically doable,” Polhemus said. “That’s the balancing point. How healthy can we get, but also make it so people are still able to afford water and to live in their homes.”

Allayud said state regulators need to go further.

“We think they are a little too sympathetic to the problems the water board has, and not as sympathetic to what consumers are faced with,” Allayaud said. “You want to be biased toward public health protections.”

Contact Joseph Geha at [email protected] or @josephgeha16 on Twitter.