Gov. Phil Murphy signed a measure allowing towns and other local governments to establish what critics have dubbed a “rain tax” but which supporters say will finance much-needed upgrades to the state’s aging water and stormwater infrastructure.

Senate Bill 1073, which Murphy signed Monday afternoon, lets those governing bodies levy a fee on property owners based on a “fair and equitable approximation” of how much runoff is generated at a particular property and in turn ends up in the local water system.

The money collected would be used to establish local stormwater utilities and finance upgrades and other fixes to aging systems.

Proponents of the measure, including environmentalists, point out that the biggest contributors to stormwater runoff are commercial properties and not homeowners.

“The biggest source of pollution we face is from stormwater runoff,” Jeff Tittel, director of the environmental advocacy group New Jersey Sierra Club, said in a prior statement. “We need to do more to clean up our combined sewer overflow because they are a health hazard.

“Raw or partially treated sewage runs during major storms are a huge concern. This could expose communities and the environment to serious contamination,” Tittel added.

Many opponents, including business groups and GOP lawmakers, decried the measure as a potentially frivolous tax.

“This legislation essentially creates a new, non-deductible property tax on the public and another bureaucratic expense at the local level,” New Jersey Business and Industry Association Vice President of Government Affairs Ray Cantor said Monday in a statement. “Churches and nonprofits, as well as residents and businesses, will all be susceptible to these added fees based on their patios, parking lots, driveways and roofs.”

Business advocates decried the proposal as a “tax on stormwater,” and several Republican lawmakers, such as Assembly Minority Leader Jon Bramnick, R-21st District, likened the proposal to a “rain tax.”

“Why should a homeowner pay a higher fee just because they have a driveway or a pool in the backyard?” Bramnick said in a previous statement.

S1073 calls for credits against the fee for property owners that adopt “stormwater best management practices that reduce, retain or treat stormwater onsite.”

“The lack of regulation and management of stormwater has caused extensive problems for New Jersey,” S1073 sponsor Assemblyman John McKeon, D-27th District, said in a prior statement. “Rainwater run-off carries with it debris, bacteria, and chemicals which can lead to pollution of our waters and drinking water sources.”