The water that comes out of the tap for more than 900,000 Californians is unsafe to drink and the state isn’t acting fast enough to help clean it up, state auditors said in a report released Tuesday.

Thousands of water systems supply the state’s 39 million people, and about 5% of them have some type of contaminant, like nitrates or arsenic, in them, according to the audit. That means people can’t safely drink the water or use it to cook or bathe. Most of the 370 failing systems are in economically disadvantaged communities, many in the Central Valley, the state’s agricultural heartland.