An estimated one million Californians are exposed to arsenic, nitrate or other chemicals in their drinking water as a result. (Yes, you read that correctly: one million people.)

The tax, which officials call a “fee,” would bring in $110 million from water utilities and about $30 million from the agriculture industry. The governor also intends to allocate $168 million toward water infrastructure improvements, which is already paid for by a bond proposition passed last year.

Clean-water activists like the proposal because it establishes a source of sustained funding to improve water infrastructure and maintain healthy levels over time. They, and the governor’s people, say it amounts to $1 on everyone’s water bill.

But critics argue that a proposed tax of any kind could backfire.

“Californians are concerned about the cost of living, and a proposed water tax is just adding to the cost of something that you have to have to live. We think it doesn’t make sense to tax a resource that is essential,” said Cindy Tuck, deputy executive director for government relations at the Association of California Water Agencies.

The political dynamics in Sacramento around the issue are also fraught, even though virtually everyone agrees that access to drinking water is an important cause. Democrats have supermajorities in both chambers of the Legislature, but several of their gains came from traditionally Republican districts where a tax increase of any size could be deeply unpopular.