A 47-year-old water main broke early Monday morning in southwest Napa, spilling about 2 million gallons of water.

The concrete pipe broke at a collar, or joint, around 2:40 a.m. along Golden Gate Drive near Stewart Ranch, which is known locally as the home of distinctive black and white cows. It took until around 7:30 a.m. to completely stop the flow, said Joy Eldredge, the city’s water general manager. That’s because it took some time to find the valve for the large pipe, then clear the area of debris so that it could be turned off, Eldredge said.

Some customers may have seen a temporary loss of water pressure as a result of the leak, but the city was able to avoid cutting off anyone’s water supply, Eldredge said.

The break comes at a time of severe drought around the region, when cities including Napa are encouraging residents to conserve as much water as they can.

Two million gallons of water is equal to a little more than six acre-feet. Napa uses about 15,400 acre-feet in a year. Eldredge said the amount of water lost is equivalent to the amount the city might see water use increase on a particularly hot day.

The break was first reported by the Napa Valley Register.