Officials on both sides of the talks did not release details from the session.
The company, which supplies water to Claremont, Barstow, Apple Valley and other municipalities, has been under fire for a proposed rate hike of more than 24 percent in 2013 and further increases in 2014 and 2015.
The new rates would have Claremont residents paying far more for their water than their neighbors in surrounding communities, city officials said.
Claremont officials have offered to buy out the company's local assets for $54 million, but Golden State officials have said the offer was merely a feint intended to pave the way for an eminent domain takeover by Claremont.
In December, the company released a feasibility study, which said those assets were worth up to $204 million.
The two sides have not been able to gather since their public quarreling started because of an assortment of scheduling conflicts - until Friday.
Representatives acknowledged the meeting, but had no other comment on the matter.
While the two sides haven't historically been able to agree on much, they spoke with one voice Friday afternoon:
"Golden State Water Company and Claremont officials today had a very productive meeting and discussed issues of mutual interest," Denise L. Kruger, senior vice president of regulated utilities for Golden State said in a statement released by the company.
"We had a very positive meeting and discussed issues of mutual concern," Claremont City Manager Tony Ramos said.
The closed meeting took place at the law offices of Best Best & Krieger in Riverside. The law firm represents Claremont.
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