Septic System Installation in Narragansett, RI

Where Narragansett has town sewer and where homes use septic

Narragansett's sewer system has two halves. The north end and the Pier area flow to the regional plant on Westmoreland Street, which South Kingstown runs. The south end, Galilee included, flows to the town's own Scarborough plant, built in 1983. Between them, the town keeps about 100 miles of sewer and 19 pump stations.

The plan counts more than 700 septic systems on Great Island and Harbor Island, both on Point Judith Pond. Smaller pockets sit near Point Judith and along Sunset Boulevard. On the north end, the south tip of Bonnet Point and the Wandsworth Street area are on septic too. Around Wesquage Pond in Bonnet Shores, a 2024 RIDEM plan puts a third of the watershed on septic or cesspools.

The plan assumes every north end system will tie in to sewer within its 20-year horizon, with one exception. Homes east of Boston Neck Road and north of South Ferry Road stay on septic. For the south end, the town plans sewers for nearly the whole area as funding allows. Each new line still takes a set process.

The town's policy calls for a petition from at least a simple majority of the owners in the area. A town-wide vote on the borrowing follows, and the homes served repay it through assessments. Past programs gave each developed property one year to connect. Our sewer line repair and installation work covers the new lateral from the house to the main.

Sump pumps and downspouts may not drain into the town's sanitary sewer. RIDEM's rules keep roof drains out of a septic system as well. Either way, that water needs its own outlet, such as a dry well from our drainage systems work.

Why is septic design harder on Narragansett soils?

The sewer plan says about 80 percent of the town sits on glacial till. Till is a packed mix of boulders, gravel, silt and clay. Some layers in it barely pass water, and low spots stay wet. By the town's count, about 73 percent of its soils pose severe limits for septic systems.

Federal soil maps tell the same story. The three most common soils in town on NRCS maps all formed in dense till. In the poorly drained one, Stissing, the seasonal high water table sits less than a foot down. In the other two, it sits about two feet down.

Town zoning maps a High Water Table Limitation Overlay District. In its A district the water sits 0 to 18 inches down, and the land is typically wetland. In the B district it sits 18 to 36 inches down. The plan says building there usually takes sewer or major drainage work.

Along the Narrow River and Point Judith Pond, the ground turns to sandy outwash. It drains fast, and the plan warns it may not treat septic effluent well. RIDEM's rules want the seasonal high water table at least two feet below the original ground under a leach field.

That is why our septic system design work starts with test holes where the leach field will go. When the water table reading is unclear, RIDEM's rules call for wet-season readings from January 1 to April 1.

Septic rules near the Narrow River and Point Judith Pond

RIDEM's septic rules set two critical resource areas that reach into Narragansett. One is the Narrow River watershed. The other is the Salt Pond area, which takes in the land that drains to Point Judith Pond. The Coastal Resources Management Council (CRMC) drew both lines in its special area management plans.

Inside both areas, RIDEM requires nitrogen-reducing technology for new construction and alterations, and for most repairs. The narrow waiver covers a repair that replaces only the septic tank. Among other tests, the leach field must not have failed and must sit over 200 feet from the coastal shoreline. To count, the technology must cut total nitrogen at least in half, to 19 milligrams per liter or less.

Where the seasonal high water table sits two to five feet down, the site rules narrow the options. A leach field there needs a technology RIDEM has approved for that ground, or a shallow trench layout. Wetter ground than that is off limits, with a 25-foot buffer. In several soil categories, the stone's base must sit four feet above that water, a foot more than elsewhere.

The water behind these rules is under strain. RIDEM lists both the Narrow River and Point Judith Pond as impaired by fecal coliform bacteria. The town's plan says the river has been closed to shellfishing from 1989 on. It names septic systems close to the water as one source that new sewers would address.

Nitrogen-reducing systems also need regular care. The extension service says advanced systems generally need service once or twice a year by a trained provider. Where RIDEM's approval requires it, the owner keeps an operations and maintenance agreement for the life of the system.

Older homes, cesspools and the town's four-year pumping rule

Narragansett's housing runs older. Census estimates put the median home's build year at 1975, and about four in ten homes predate 1970. More than eight in ten are single-family detached houses, and about one in four was counted as seasonal in 2020. Census permit counts show 11 new single-family homes authorized in 2025.

RIDEM notes most home systems installed after 1970 are not cesspools, so older lots off the sewer deserve a look. State law requires a cesspool to be replaced, or the house tied to sewer, within 12 months of a sale. A failed cesspool must be abandoned within a year of discovery. Cesspools within 200 feet of the tidal shoreline had to go by January 1, 2014.

A 1992 town ordinance requires every septic system in town to be pumped at least once every four years. The town's 2005 plan called it the state's first septic pump-out ordinance. Each pump-out is recorded in the town's online tracking system.

RIDEM's rules count a system as failed when wastewater surfaces over the leach field or backs up into the house. Our septic system repair work starts with finding the cause. When the answer is a new system, the design package goes to RIDEM for approval.

RIDEM approves the septic design, and the town's Building Inspection Department issues the building permit. The same office enforces flood zone requirements and ISDS regulations, the rules for individual sewage disposal systems. Under RIDEM's rules, the town cannot issue a building permit until the required state approvals are in hand.

The building permit's site plan needs a registered land surveyor's stamp. It must show any wetlands and water bodies within 200 feet, plus the flood zone elevation. Town zoning also sets development standards for homes with more than four bedrooms. Call or text (401) 474-8926 to set up a look at a Narragansett lot.