If you’re curious about what toxins may be in your tap water, a tool from the nonprofit Environmental Working Group will tell you, but you may not like what you find.

EWG’s Tap Water Database breaks down detected contaminants by zip code and how much of each substance was found.

As the Los Angeles Times notes, however, it’s important to consider that EWG’s standards differ from the maximum levels prescribed by federal and state governments.

Keep that in mind when the Tap Water Database tells you, for instance, that the Los Angeles Department of Water and Power’s water contains 430 times more arsenic than EWG’s guidelines.

Despite alarming figures like that, Jonathan Leung, the LADWP’s director of water quality, told the Times that “there’s no health concern,” as levels of arsenic and other contaminants meet federal limits.

“That’s where, collectively, all the toxicologists and water quality specialists and scientists have worked together to set national standards,” he said. “As a water quality utility, that’s what we set our sights on. The public should take confidence that the legal limits are protective of public health — and we strive to do better than that.”

Scientists seem to be in agreement with Leung. Water researcher Daniel McCurry of the University of Southern California said he drinks water straight from the tap without concern, the Times reports.

If you’re still worried about possible carcinogens like nitrate and uranium, however, the EWG has a guide to water filters.