About 3,000 City of Madison water customers — as well as businesses in the downtown area — woke up without water Saturday after a broken main on Vaughn Drive led to an outage at about 3 a.m.

Customers reported a drop in pressure sometime after 2:30 a.m. and Ron Geyman, a water department employee, said he was called out at 3 a.m. to investigate the problem. The outage was discovered to be a split in a 12-inch main — the city’s next to largest pipes downtown behind the 14-inch mains on Main Street — several feet under the pavement on Vaughn Drive.

Workers from Sedam Contracting were quickly called in to make repairs, using a small track hoe to excavate the site and three gasoline pumps to clear the hole of water so that Greg Foley could access the area to assess the damage and plan a repair.

Geyman said the leak was losing about 400 gallons a minute but that it was fortunately a small split that can be repaired with a patch and clamp. A bigger split would have necessitated resecting a longer area of the pipe.

Geyman did not have a time frame for completing repairs but noted customers experiencing low to no water pressure — essentially everyone in downtown Madison — would need to boil water intended for consumption for at least 24 hours after service resumes. Water used for consumption must be boiled for 3-5 minutes. For dish washing in private residences, a few drops of bleach per gallon of water will also provide adequate disinfection.

Geyman said it is not known if the break is related to the city’s ongoing project to drain, clean and repair water tanks but that discolored water in some parts of downtown Madison were most likely related to that earlier in the week when work began on the tower on the hillside at the east end of the city.

“We’ve got no way of knowing what caused it but any change in pressure can cause changes in the pipes,” Geyman said, “Especially pipes as old as these.”