Edgartown, Oak Bluffs, Vineyard Haven and West Tisbury town officials received their marching orders this month - recommendations for steps these Island towns should take to protect and enhance public water supplies in order to keep pace with future development.

A study released by the Martha's Vineyard Commission last week, funded with grants from the state's Executive Office of Environmental Affairs Watershed Initiative, examines the readiness of down-Island towns to provide municipal water to new homes. The report also evaluates the effectiveness of existing regulations designed to limit nitrogen loading in sensitive areas surrounding town wells.

"It's a complicated world - water is," said Jo-Ann Taylor, the Martha's Vineyard Commission coastal planner who took the lead on the study, as she thumbed through the report's 118 pages.

The entire Island has been designated a sole source aquifer - with water flowing west to east at depths 70 feet below sea level and again at 90 feet below sea level.

Edgartown, the report says, needs to secure more sites for municipal water wells - bracing itself for a potential 2,316 more dwellings on the town's 4,666 acres of land which can be developed. It is expected that the town will provide water service to Arbutus Park, Ocean Heights and parts of Katama in the coming years - increasing the percentage of residents on town water from 62 to 85 per cent.

"Edgartown doesn't have enough capacity for buildout. And you can't use limited capacity as a tool to stop growth," Ms. Taylor said. The town's water commissioners are considering a parcel of town-owned land in the Pennywise Path Preserve area as well as talking with the state Department of Environmental Management about the possibility of securing easements over acreage in the state forest. Use of the state forest must be okayed by the state legislature.

Edgartown water superintendent Fred Domont said that, in addition to planning for additional growth, the water department must also look ahead to the eventual closing of the Mashacket well - which has lately been producing water with high iron content.

The MVC report also urges West Tisbury to move forward with laying out the infrastructure for a town water system - taking advantage of the Greenlands, 380 acres of land northeast of the state forest that the town secured for future water needs in the early 1980s.

"West Tisbury thinks of themselves as rural and pastoral, but with their growth rates, they may need to think about a municipal water supply," Ms. Taylor said.

The report finds that wells in Tisbury and Oak Bluffs are adequately equipped for current and future demands - although Ms. Taylor urges these two towns to carve out space for a backup supply.

"Tisbury and Oak Bluffs have enough supply, but if something happened - you can't plan when you get there," Ms. Taylor said. "The unthinkable sometimes happens. Towns have to be prepared."

The Oak Bluffs water department now serves 3,840 homes - practically all the residences in the town. The town is close to buildout - with capacity for only 820 more homes, all of which could be served through the Farm Neck and state forest wells. Similarly, Tisbury has nearly completed its growth under current zoning, with room for only 1,000 more dwellings. Tisbury's municipal water system currently serves 76 per cent of its dwellings or 2,720 houses.

The three down-Island towns, the report recommends, should tap into West Tisbury's Greenlands district - utilizing the bountiful water source beneath the wooded property. A test in 1982 found that the site could pull as much as one million gallons of water a day from the aquifer - a treasure that the property's management plan said other Island towns may be granted rights if they've exhausted other options.

"It's time to do some nuts-and-bolts planning. It's time for Edgartown, Oak Bluffs and Tisbury to start knocking on West Tisbury's door," Ms. Taylor said.

Such coordination will largely depend on piping easements through the state forest - requests that should begin at once with the state Department of Environmental Management. The report also urges Oak Bluffs and Tisbury to acquire or conserve land north of the state forest and Edgartown east of the state forest - protective measures to guard against nitrogen loading in these potentially sensitive areas.

By and large, the study found that Oak Bluffs, Tisbury, Edgartown and West Tisbury have sufficiently protected the land surrounding municipal wells - areas the Department of Environmental Protection deems Zone II areas because of the ability of contaminants in these properties to reach the well. Towns enforce limited septic discharge within Zone II areas, allowing only one bedroom per 10,000 square feet of land.

"Existing protections are fine. Towns have done a good job," Ms. Taylor said.

But Ms. Taylor highlighted some high-risk land uses operating within Zone II areas - operations well under way before the state adopted regulations for and outlined Zone II areas in the early 1990s.

Ms. Taylor urged more regular inspections of several potentially detrimental land uses:

* A single zone II is used for all three wells in Tisbury. Potential hazards include Nip 'n' Tuck Farm, Heather Gardens, parts of Chicama Vineyard, Tashmoo Farm, the Park and Ride lot, the Tisbury landfill and the abandoned septage lagoons. Carroll's Trucking, Wooden Tent Photo and Michelle Gerhard Jasny veterinarian clinic could also pose threats to Tisbury's wells.

* The four municipal wells in Oak Bluffs, one of which is not yet in service, are protected by two Zone II districts. The Lagoon-state forest Zone II could be harmed by NSTAR, the White Brothers asphalt plant, Whippoorwill Farm, Norton Farm, Thimble Farm and Chicama Vineyard.

* Oak Bluffs' Farm Neck Zone II faces possible contamination from high density residential development, six automotive repair shops including John Leite's Auto Salvage yard, part of Farm Neck Golf Course, the high school, Community Services, the ice arena, Oak Bluffs landfill, the transfer station and abandoned septage lagoons.

* Edgartown is covered by two Zone IIs for the town's four wells. The Wintucket-Quenomica Zone II faces only one threat - the Vineyard Golf Club. The Mashacket-Lily Pond Zone II could be harmed by any of the 46 commercial businesses in this area, a veterinary clinic, the Massachusetts Society for the Prevention of Cruelty to Animals, the driving range for Edgartown Golf Club, the town landfill, the town wastewater treatment plant, Morning Glory Farm and Sweetened Water Farm.

Current nitrogen loading measurements indicate that none of the Zone IIs are in present danger of contamination. Hazards from septage lagoons and Tisbury and Oak Bluffs, Ms. Taylor, can't yet be quantified.

"Nitrogen from septage lagoons - it remains to be seen the effects," she said, noting that these chemicals travel well in water, passing first into the wells, then on to the Island ponds. "Once it gets in, it's hard to get rid of," she added.

Other recommendations the MVC made in this report include:

* Establishing a management plan for the state forest.

* Toughening regulations for nitrogen loading limits within the state forest aquifer protection district.

* Sampling of landfills at least every six months.

* Reminding the departments of public works crews to not salt roads in Zone II.

* Creating a central database of underground fuel tanks and halting delivery of fuel until each site is registered.

* Drawing a Zone II perimeter around the Greenlands district.

* Strengthening an emergency use plan between down-Island towns from a gentlemen's agreement to a firm contingency plan.