Water restrictions have been placed on residents and businesses in Montgomery and Prince George's counties after a main break in Chevy Chase that resulted in an estimated loss of 60 million gallons of water, officials said.

The break occurred at about 8 p.m. Monday in a 54-inch pipe at the intersection of Connecticut Avenue and Chevy Chase Lake Drive. Washington Suburban Sanitary Commission officials said that the break led to a geyser that shot about 30 feet into the air.

WSSC workers have not yet been able to determine the cause of the break. Natural gas and electric lines run alongside the water main, and employees from Baltimore Gas and PEPCO were working Tuesday morning to secure those lines so that work can begin on the pipe.

The mandatory water restrictions could last a week and are necessary to allow the system to replenish while the pipe is repaired, officials said. Customers are told to:

-- Take shorter showers and turn off faucets after washing hands and while brushing teeth

-- Limit flushing toilets

-- Put off washing clothes if possible

-- Limit dishwasher use and only wash full loads

"Please don't hoard water. We're not running out," WSSC General Manager Jerry N. Johnson said in a statement. "But if everyone can cut their water use by 10 percent we should be OK. We appreciate everyone's understanding and cooperation."

No WSSC customers are without water because of the break, officials said. Those who violate the water restrictions could receive a fine of up to $500.