Test results show that Arlington County is in compliance with Environmental Protection Agency standards for lead and copper in its drinking water, officials announced last week.

The county tests, which are mandated by the EPA and conducted every three years, found that none of the 50 homes tested exceeded the EPA action level of 15 parts per billion for lead and 1.3 parts per million for copper, the scientific measurements used to determine how much of the elements are in the water.

"We have always been and continue to remain in compliance with the EPA regulations," said Michael Collins, the county's acting engineering supervisor for water, sewers and streets. "There's no reason to be concerned about drinking water that is being delivered to customers' homes."

The Arlington County Department of Environmental Services conducted the tests over a one-month period starting in June. The tests are meant to be taken during the hottest months of the year, when the presence of lead is likely to be the highest, said Diana Sun, a county spokeswoman.

The 50 homes selected for testing were chosen because they were built between 1983 and 1986; houses constructed during that time had the highest likelihood of elevated lead and copper levels due to the plumbing materials commonly used then, Sun said.

"Those years, lead solder was allowed to be used when joining copper piping," Sun said. "So that's why the EPA needs to test these homes. . . . They feel those are at the greatest risk."

Although none of the samples taken from the homes surpassed the action levels of 15 parts per billion for lead, one home matched it, the results showed. The homes tested were selected after the county conducted a random mailing to 285 homes -- out of the 635 homes in the county that met the EPA criteria -- asking homeowners to participate in the survey. Fifty-five homeowners responded, according to a county news release.

The highest lead level found was 15 parts per billion and the highest copper level was 0.45 parts per million, officials said.

Since the EPA's 1992 Lead and Copper Rule was enacted, Arlington has always been in compliance, Sun said. Because the county has remained in compliance, testing is done every three years versus every year, she said.

The latest tests come after the county in April released the findings of comprehensive testing that was conducted after the disclosure of high lead levels in the District's water supply. There was concern that potentially corrosive water from the District's Dalecarlia Water Treatment Plant, which also supplies water to Arlington, may have contaminated the county's supply.

In that testing, water from 127 homes was tested, and officials found that only five had higher than acceptable lead levels.

Arlington is not scheduled to conduct the EPA-mandated testing again until summer 2007, Collins said.