San Francisco is the latest community that regulators have told to stop taking some river water during the drought despite the city's decades-old water rights.

The State Water Resources Control Board on Friday ordered the cutback under its latest round of notices that waterways are too dry to meet demand in the drought.

Its cutbacks have involved water districts and corporations generally spared from water cuts because of their strong claims.

San Francisco's rights to Tuolumne River water date to 1902 when the mayor nailed a notice on a tree. Water is diverted from the river to fill the Hetch Hetchy reservoir that serves millions of people in the San Francisco Bay Area.

It's not clear how much river water cities take under the rights that were suspended Friday. Communities can keep drawing water already in the nearly full reservoir.