It's early in the process, but more than half the Montgomery County schools tested so far have shown elevated levels of lead in their drinking water. Find the worst offenders, and where you can check to see which schools have been tested.

WASHINGTON — More than half the Montgomery County schools tested so far have shown elevated levels of lead in their drinking water.

The district has released results from the first batch of tests of the 205 schools in the county, and so far 12 of the first 21 schools tested have been shown to have lead levels higher than the 20 parts per billion mandated by the Environmental Protection Agency.

Eight of the 12 offending schools are elementary schools: Gaithersburg, New Hampshire Estates, Pine Crest, Rock View, Rolling Terrace, Strathmore, Summit Hall and Viers Mill. Other schools found to have high lead levels so far are Eastern Parkland and Sligo middle schools, and Northwood High School.

The tests, conducted by contractors hired by the school system, show widely varying results even within schools. For example, at Gaithersburg Elementary School, only two of the 96 faucets and drinking fountains showed higher lead levels than permitted. But the highest, a fountain in Classroom 14, showed the highest level in the system, at 253 parts per billion — more than 10 times the legal limit.

At Eastern Middle School, four of the 43 fountains and faucets tested at more than 20 parts per billion, including the fountain between rooms 804 and 806, which came out at just short of 65 parts per billion.

Neighboring school districts have more stringent standards. Prince George’s County set its lead standard at 10 parts per billion; in D.C. schools the standard is 5 parts per billion.

The testing began in February, said Gboyinde Onijala of the school system. The testing came in response to a Maryland law that requires all schools be tested for lead in their water by July 1. She said they are testing on a city-by-city basis.

She said that most of the offending water outlets were faucets, not drinking fountains available to students, that any outlets that are above the EPA standard have been taken out of use and remediation has begun.

Onijala added that the schools’ water had last been tested between 2004 and 2007 in what she described as “an extensive water testing and water remediation program.” She also said results would be posted as they’re ready on the school system’s website.

Laura Stewart, capital improvements program chair for the Montgomery County Council of Parent-Teacher Associations, said she was “a little surprised that a lot of different schools are having one or two failures.”

She added that there are many ways a high lead level can show up, including corrosion in the fountain itself, or lead in the solder or the copper piping.

“A lot can happen in 10 years,” she said, referring to the last time the system had been tested. She added that she was happy the results are being posted right away, especially given that they’re not required to put out the results if tests come back under 20 parts per billion: “They put everything out in the system and I appreciate that.”

WTOP’s Megan Cloherty contributed to this report.