If you're concerned about drinking unfiltered water from your tap at home, bottled water isn't automatically the safer option. As USA Today reports, tests conducted by the California nonprofit Center for Environmental Health (CEH) found that the arsenic levels in two popular bottled water brands exceed those found in the state's tap water.

The affected brands are the Keurig Dr Pepper-owned Peñafiel and Whole Foods-owned Starkey. The arsenic content in each product hasn't prompted a federal recall, but CEH discovered that it does violate state guidelines. CEH sent notices to both companies informing them that their products must be printed with health warnings disclosing the presence of arsenic under California’s consumer protection law Proposition 65.

Arsenic is safe, and often unavoidable, in very small amounts, but in high concentrations it can be harmful. Drinking water with unsafe levels of arsenic can lead to cancer, reproductive problems, and developmental issues in children.

An earlier report released by Consumer Reports in April found that the same brands analyzed by CEH had twice the federal limit of arsenic in their bottled water. Keurig Dr Pepper stopped production of its Peñafiel water, which is sold at Target, Walmart, and elsewhere, for two weeks following Consumer Reports's tests. Starkey water bottles are sold at Whole Foods.

Even if they meet safety standards, many popular water brands contain trace amounts of arsenic. Consumer Reports has found acceptably low arsenic levels in Aquafina, Dasani, Evian, Deer Park, Fiji, and Poland Spring products.

[h/t USA Today]