Amid mounting concerns over the quality of Cambridge's water supply, city officials are beginning to criticize the infrastructure of the reservoir system and to question the competence of its management.

Sentiment on the nine-member City Council has been building against the Water Department since January, when the city sent out letters saying they had recorded high levels of trihalomethanes--chemicals known to cause cancer in laboratory animals--from July 1988 to December 1989. During that period, the department failed to notify water users of the problem, as required by law.

The water problems have lost the department some long-time allies, and last night even prompted an order by Councillor Edward N. Cyr calling for the formation of a rewiew commitee to assess the water quality, the management, the capital improvement needs, and the use of consultants by the water department.

Council members have expressed concern at the ability of the department and Water Superintendent John J. Cusack, Jr. to manage its problems, arguing that the agency is plagued by low morale which is created, in part, by management.

"For a long time I was a supporter of the Cambridge Water Department. Now I am beginning to wonder about it myself," said Councillor Sheila T. Russell.

Other councillors feel the need for change is not in the leadership of the department but the equipment used to regulate the system.

"I don't know if we should be changing the building personnel," said Councillor Walter J. Sullivan. "But certainly the building should be brought up to date."

Many councillors--among them Mayor Alice K. Wolf--have suggested that the city may need to construct a new plant to solve problems in the water system. Others, including Councillor Jonathan S. Myers, have balked at this plan, saying the city should conduct an independent review before going ahead with such a plan.

Councillor William H. Walsh estimated the cost of a new plant at $300 per taxpayer, but added that he believed the public would be willing to shoulder the cost.

"People are petrified of the water," Walsh said. "People are willing to spend that money to improve the system."

Russell said that she has received many calls from people concerned with the water, adding that she herself has lost confidence in the safety of Cambridge water.

"I won't drink the water myself--I've resorted to bottled water," said Russell.

Myers said he had not seen the same level of concern but he acknowledged that the public is wary. "I can't say my phone has been ringing off the hook, but there is a general level of concern," said Myers.