US actor Tom Selleck has struck a "tentative" deal to resolve allegations he stole water from local authorities in drought-stricken California, an official said Friday.

The veteran "Magnum P.I." star was accused of procuring deliveries of water taken illegally by truck from a fire hydrant in Thousand Oaks, northwest of Los Angeles since 2013.

The Calleguas Municipal Water District accused the 70-year-old of illegally moving water to his 60�acre Hidden Valley estate, according to court documents cited by the Los Angeles Times.

But the district's resources manager Eric Bergh told AFP that a provisional agreement had been reached to resolve the row. The deal still has to be approved by local authorities next week.

"We are pleased and believe the tentative settlement is a positive step towards an ultimate resolution of this matter," he said.

"Staff intends to recommend Calleguas' Board of Directors approve the settlement at its meeting next Wednesday," he added, declining to give any further details.

According to the LA Times, the water district spent some $22,000 on a private investigator to track the deliveries, which were first observed in September 2013.

Representatives for Selleck did not respond to requests for comment on the case.

California is in the fourth year of its worst-ever drought. In April the western US state's governor Jerry Brown announced sweeping statewide water restrictions for the first time in history.