Gov. Jerry Brown and state lawmakers are rebooting an effort to pass a new tax to attack unsafe drinking water in California.

But there’s a twist: The proposed tax on water bills would be voluntary, increasing its chances of success among skittish lawmakers in an election year.

After calling off a plan in June to apply a mandatory tax on water bills, the governor is backing a new pair of bills that would apply a voluntary levy on ratepayers to fund safe drinking water projects. Senate Bill 844 and 845, introduced by Sen. Bill Monning, would also raise taxes on dairies and fertilizer manufacturers.