PORTSMOUTH — Town Councilman Peter J. McIntyre says he wants to go on record against paying for any additional engineering work on the town’s draft wastewater facilities plan.

The majority of the Town Council on Monday approved a $152,000 addendum to the study, which proponents say will give voters all the scientific data they need to decide whether the town should have a sewer system in one or more neighborhoods.

During Monday’s vote, council members Hubert E. Little, a Republican, and Karen Gleason, an independent, both opposed expanding the study from the $229,200 already committed to a new total of $381,200.

But McIntyre, a Republican, remained silent, and his silence was taken for assent with the Democratic majority.

A moment later, after reporters had left the council chamber, McIntyre asked to have his vote changed.

He said he had made a mistake, according to the minutes of the meeting. The final vote was 4 to 3 in favor of expanding the study by consulting engineers Woodard & Curran.

The work, which originally centered on solving water-pollution problems in Island Park and Portsmouth Park, was expanded to include an analysis of Common Fence Point, three small neighborhoods opposite the post office, and 10 clusters of homes in various sections of town, the largest being Redwood Farms off West Main Road at Union Street.

The added work also will cover cesspools — which must be phased out by 2013 — and septic systems older than 40 years.

Among other things, McIntyre said yesterday, he had not been satisfied at the meeting with the answer a Department of Environmental Management official gave when McIntyre asked him whether the DEM could sue the town if voters reject a bond issue for a sewer.

John J. Manning, DEM’s principal sanitary engineer, had replied that the agency could take the town to court if untreated wastewater gets into the town’s storm drains and the town fails to take steps to correct the problem.

All the engineering work done so far on the issue has concluded that a sewer system is the only solution guaranteed to address water-pollution problems in Island Park and Portsmouth Park, two of the town’s most densely populated neighborhoods.

There has been no pollution problem reported in Common Fence Point, although questions about contamination have been raised in other spots in town that will be studied by the engineers.

At Monday’s meeting, Manning likened the need to study wastewater treatment outside Island Park and Portsmouth Park to the advisability of someone at risk for a heart attack or stroke changing their diet or lifestyle, the earlier the better.

Town Council President Dennis M. Canario offered his own medical analogy. He likened the possibility of too much intervention to the notion of doctors performing the wrong medical procedures.

But Manning said he would take odds on his own comparison over Canario’s. Canario, a Democrat, ultimately voted for the study, along with fellow Democrats James A. Seveney, Leonard B. Katzman and William E. West.

The expanded engineering study, which will make recommendations on the basis of soil conditions, lot sizes, and the age of existing septic systems, is to be completed by the end of the year. A referendum on a sewer bond would be held in 2009.

gmacris@projo.com