University officials announced Friday that water in 21 campus buildings has tested positive for lead.

The affected buildings are generally “small, townhouse-sized properties,” wrote Matt Nehmer, assistant director of Media Relations, in an e-mail Friday night. While the University is notifying the affected buildings’ residents, it has declined to publicly announce which facilities exceed federal contamination limits.

The two-part lead tests, which began two weeks ago, consisted of examining the concentration of lead in water upon immediately turning on a faucet and again after letting water flow for several minutes. Officials found that 20 buildings had high lead levels in the first test while one University-owned private residence failed both tests.

The decision to conduct tests came after officials discovered a lead pipeline serving the Judaic Studies townhouse at 2142 G St. last month. According to the D.C. Water and Sewer Authority, more than 23,000 buildings across the city could be affected by lead contamination.

Nehmer said finding lead in the first test was not significant because the contaminated water had been stagnant in pipes for several hours and is not indicative of the water’s usual quality. Lead primarily enters drinking water as pipes corrode.

“(I)t’s important to note that second draw samples are more indicative of the water quality coming into the building during normal use,” he said.

The University is trying to work with WASA to remedy the high lead levels, Nehmer said.

“At this time, WASA has been given all of our sampling results,” Nehmer said. “We are now discussing with WASA what actions, if any, they recommend for our buildings based on the results obtained.”

But WASA officials said that there is little help the agency, which is the sole provider of water to the city, can offer to institutions such as GW.

“We don’t go into every building that has high lead levels and do something,” said Marilyn Stackhouse, a WASA spokeswoman. “We have a priority list, and we look at all the lead pipes in the city, especially in areas where there are high-risk individuals living.”

GW used an independent contractor to take water samples from all 135 buildings on the Foggy Bottom and Mount Vernon campuses. GW paid for the testing, but officials declined to discuss cost.

Students concerned about lead contamination should follow WASA safety tips, including running water for several minutes before consumption.