SACRAMENTO, Calif. — Maybe you've heard buzz this week about cancer-causing chemicals in California's tap water.

That's because an article published Tuesday in the journal Environmental Health said toxins in our drinking water could lead to more than 15,000 additional cases of cancer statewide.

But what’s behind that number?

First—some context.

The study was conducted by the Environmental Working Group, which describes itself as "a non-profit, non-partisan organization dedicated to protecting human health and the environment."

Researchers there looked at state data publicly available through California's Safe Drinking Water Information System. They analyzed contaminants in more than 2,737 community water systems from the year 2011 to 2015. The vast majority of Californians get their water from these systems.


Here's what they found.

In California, 90 percent of water systems met all federal standards for the past seven years. Great, right?

But just because levels are legal doesn't necessarily mean they're safe, according to researchers.

The greatest risks in our drinking water are from substances including arsenic, byproducts of disinfectant chemicals and chromium-6, AKA the "Erin Brockovich" chemical, if you recall that movie.

By looking at the way these chemicals interact in our water, researchers said they've identified more than 15,000 additional cases of cancer that could occur statewide over the next 70 years.

The study found drinking water risks are higher in small- to midsize-communities, which are often the ones in need of expensive improvements to their water infrastructure.


The Environmental Working Group wants government health officials to look at the way contaminants in our water interact. Currently, state and federal standards look at them one-by-one. When mixed together, the EWG claims, some of these chemicals could be harmful in ways the government is not yet measuring.

So what can you do about it?

First, you can use a tool on the Environmental Working Group's website to find the details on your water system.

In the City of Sacramento’s main water system, for example, researchers analyzing public data found six contaminants with levels above health guidelines and 11 other contaminants.

City of Sacramento Main Water
The Environmental Working Group

You can check out the State Water Resources Control Board's website to determine your water source.

Fortunately, most of these contaminants can be eliminated using a filter.

California Gov. Gavin Newsom is pushing legislation that would establish a drinking water fee to help improve tap water in communities that need it most. Critics have called it a water tax. That bill is still working its way through the state Legislature, so chances of it passing are, at this point, unknown.

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