Michael S. Marcotte, the D.C. Water and Sewer Authority's chief engineer, has resigned from the agency to take a position as the head of public works in Houston.

Marcotte, 53, has been the top engineer at WASA since 1997 and led the agency's technical response to findings of excessive lead in much of the city's drinking water.

His resignation, effective July 9, follows a period of intense pressure on the agency from city and federal officials, who have complained that WASA failed to respond quickly to the lead problem and did not fully inform the public of health risks.

Marcotte and WASA General Manager Jerry N. Johnson declined to comment through a spokesman yesterday. Agency sources said Marcotte was not fired and was considering leaving WASA before the lead problem created a public outcry four months ago.

Yesterday, Glenn S. Gerstell, chairman of WASA's board of directors, called Marcotte's departure "a significant loss."

Marcotte "has tremendous institutional knowledge," Gerstell said. "On the other hand, this is probably a logical jumping off point, because we have now largely reached the first level of addressing the elevated lead levels, having gotten the filters out, figured out the scope of the problem and begun the water chemistry changes."

WASA spokesman Johnnie Hemphill said the agency will conduct a national search for Marcotte's replacement.

Marcotte, Johnson and Chief Financial Officer Paul L. Bender have been in charge at WASA almost since the inception of the quasi-independent agency in 1996. Some residents, city leaders and environmentalists have complained that they failed to accept public input.

"It's definitely time to have a turnover in the senior management of WASA. They've got to do something to restore the public trust," said D.C. Council member Adrian M. Fenty (D-Ward 4). "I hope it's part of a wholesale turnover in an agency that really needs it."

Brent Blackwelder, president of Friends of the Earth, an environmental group, said WASA should seek to replace Marcotte with "somebody able to communicate with the public and tell the truth about the water problems . . . and seek [community] participation in the solution."

Even before high levels of lead were found in thousands of homes last year, Marcotte's division faced major challenges. The agency has been preparing to spend about $1.76 billion for capital improvements in the next 10 years, including upgrades at the Blue Plains Wastewater Treatment Plant.

But the agency's management of the lead problems has occupied most of Marcotte's time since February. City leaders and residents complained that the agency had not disclosed the problems after learning of them last year. Under pressure, WASA has conducted thousands of free water tests in recent months, ramped up its lead service line replacement program and answered questions at dozens of neighborhood meetings and congressional hearings. Marcotte participated in many of those hearings.

On Thursday, the U.S. Environmental Protection Agency concluded that WASA violated the federal Safe Drinking Water act in several ways.

"I found from listening to [Marcotte] at hearings that he did have the data at his fingertips, but it seemed like the agency had such a campaign to spin it that he was prevented from telling all the information he knew," said Liz Pelcyger, a mother who lives on Capitol Hill.

Michael S. Marcotte has been a key figure in WASA's response to lead contamination in D.C. water.