by Pat Loeb

PHILADELPHIA (CBS) — The Philadelphia Water Department will change the way it tests for lead in tap water, in response to state recommendations and new EPA guidance.

Lead testing received new scrutiny after high levels were found in tap water in Flint, Michigan.

Philadelphia’s practice of instructing residents to remove aerators and let the water run before taking a sample was much criticized, but Water Department officials maintained they followed EPA guidelines.

New EPA guidance, however, specifies that aerators should remain on and samples should be taken immediately, not after flushing the pipes.

A release from the department says, as a result, it will begin testing a minimum of 50 homes in the next six months, at least half of which are likely to have lead service lines.

Officials declined further comment, citing a class action suit filed last month alleging that the city hid high lead levels from residents.