WILMINGTON (CBSLA.com) — Residents and activists protested outside the Tesoro Oil refinery in Wilmington Wednesday claiming the company won’t pay its water bill.

Executives from the Water Replenishment District of Southern California (WRD) and a group of supporters, are calling on the refinery to pay its water replenishment fee.

(credit: CBS)

“If they just stopped paying and stopped pumping it would be no problem, but they stopped paying and continue to pump,” WRD president Albert Robles said.

Robles said Tesoro hasn’t paid its bill for the past four months.

South Gate Mayor Bill Dewitt said his city pays its water bills.

“If these folks don’t pay, and they’re large consumers of groundwater, then our citizens have to make up the difference,” Dewitt said.

However, there are four cities in Southern California that have also stopped paying. They’re involved in a legal battle over water rates which Tesoro deemed “unconstitutional.”

Tesoro released a written statement which said, in part: “The Superior Court of California declared replenishment assessments assessed by the Water Replenishment District of Southern California against Tesoro unconstitutional…As a result, Tesoro ceased paying such assessments pending conclusion of the litigation appeal process.”

Signal Hill, Cerritos, Downey and Pico Rivera are not paying their water replenishment fee.

“The city attorneys advised us that that is an illegal charged fee and we cannot pay at this time,” said Steve Myrter, director of public works for Signal Hill.

Myrter said a court has ruled the WRD didn’t follow the legal process in setting its rates and, therefore, the fee is illegal.

The WRD is appealing the court’s ruling. They filed a lawsuit Wednesday asking a court to compel Tesoro to pay its bill until the appeal process has concluded.