GROTON -- In the run up to next month's Town Meeting, members of the Finance Committee met with those of the Lost Lake Sewer Commission and Town Manager Mark Haddad to discuss a number of measures dealing with bringing wastewater services to the lakes neighborhoods.

The joint meeting was held as part of the Finance Committee's review of spending articles to be included in the warrant for Town Meeting and that residents will be asked to consider prior to voting on appropriations.

Among the 26 articles scheduled for the warrant are three dealing with a proposed Lost Lake Sewer district: one that would define and establish the district, another that would raise $12.9 million to pay for construction of the system, and a third that would permit the town to enter an intermunicipal agreement with Ayer for use of its wastewater treatment facilities.

In trying to determine why the Finance Committee should take a position recommending the sewer articles to residents at Town Meeting, chairman Jay Prager probed commissioners and their project engineer, Robert Rafferty of the firm of Woodard & Curran, as to exactly why an expensive new sewer system was needed.

Opening the discussion, Prager asked Rafferty to help him understand the different effects caused by the presence of phosphorus and nitrogen in the waters of the lakes.

Phosphorus entered the lakes by way of a pair of streams that enter into Lost Lake and Knops Pond, said Rafferty, and nitrogen from inadequate septic systems now used by property owners around the lakes.

Sewer Commission Chairman Carol Quinn said it was hard to judge the exact level of risk because many of the properties around the lakes were so small.

"How much of a risk the two represent is hard to quantify," said Rafferty. "What it comes down to is how much risk are you willing to live with?"

It was Rafferty's firm that first determined the danger faced by the lakes as a result of area septic systems, concluding that they were environmentally sensitive areas that should be included in any plan to expand sewer services.

Subsequently established by the Board of Selectmen, the Lost Lake Sewer Commission eventually completed its mission to come up with estimates on the cost of a building a sewer system in the Lost Lake area, identifying possible funding sources and conducting an important income survey of residents needed to qualify for state and federal grants.

It all came to a head when the town decided to pursue the option of connecting a Lost Lake sewer system with wastewater facilities in Ayer and received approval from the state for an inter-basin transfer between the two towns.

Cost for the project, said Haddad, would come to $12.9 million, with the town agreeing to cover 25 percent of it. In addition, owners of commercial property in the Four Corners, where the sewer line would pass on its way to Ayer, would pay an additional 32 percent, leaving only 43 percent of the cost to be paid by property owners in a betterment fee.

"This is the worst-case scenario for the town," said Haddad of the payment scheme.

Comparing the two projects, Haddad said planning for the new Center Fire Station was much easier. In that case, all the town had to do was to engineer it, design it, determine the cost and send it out to bid. It was a much more complicated and drawn out process for the sewer system, much of which was governed by state regulations.