WARWICK, R.I. — Enjoy shellfishing in Greenwich Bay? Thank a sewer.

Last week state officials announced they were upgrading 180 acres in the western portions of Greenwich Bay to conditional approval for shellfishing. That area had previously exceeded federal limits of fecal coliform bacteria — used as an indicator of potential sewage contamination — starting in 2002.

Scientists in the Rhode Island Department of Environmental Management’s (DEM) Office of Water Resources attributed the improvement in water quality to better stormwater control and cesspool control.

“At least statistically, the findings and trends seem to indicate getting these homes on sewer and off either failing or substandard septic systems really helped,” said DEM principal environmental scientist David Borkman.

Despite being located in one of Rhode Island’s more heavily urbanized areas, residents in coastal areas of Warwick have long resisted adopting sewer connections, citing the rising cost and a preference for existing systems.

By the year 2000, only 12.7% of all homes in the neighborhoods around Apponaug Cove had sewer connections, with the rest relying on cesspools or onsite waste systems. Thanks to an aggressive campaign from the city, and a state law mandating homeowners within 200 feet of the water remove their cesspools, the sewer system adoption rate has risen to almost 89%.

Borkman said DEM had pegged the source of much of the pollution in Greenwich Bay to Hardig Brook and many of the developments in the surrounding area, which historically did not have sewer connections.

Cesspools in Rhode Island were an aging environmental disaster. All cesspools pre-date 1968, when the state’s first regulations on septic systems went into effect. They’re considered substandard septic systems by DEM, since cesspools don’t actually treat wastewater from homes. Instead they collect it into a single concentrated underground storage unit, one that typically is in direct contact with the local groundwater, resulting in groundwater contamination.

That kind of pollution has direct impacts on the local environment, with much of that contaminated groundwater flowing down Hardig Brook and into Greenwich Bay. The bay, once known as a legendary site for scallops and quahogs, was closed to shellfishing in 1992 due to pollution levels.

With sewer connections, wastewater from these homes is routed to the city’s sewer facility, which discharges treated wastewater into the Pawtuxet River, instead of Greenwich Bay.

The state legislature passed the Rhode Island Cesspool Act to crack down on these aging systems. Homeowners were required to phase out their existing cesspools, unless they were within 200 feet of the shoreline, a public well, or other waterbody with an intake for a drinking water supply.

The state offered some assistance through low-interest loans via the Clean Water Finance Agency for residents to replace cesspools. But sewers remain expensive for residents still holding out.

In 2020 WJAR reported residents in Warwick’s Bayside, Longmeadow, and Highland Beach neighborhoods could pay anywhere from $20,000 to $25,000 to replace their existing septic systems with municipal sewers. Last year Mayor Frank Picozzi said the costs would be capped at $16,500.

The water quality has been slow to improve over the last 30 years, and to this day many of the coves and creeks on the edge of Greenwich Bay remain closed to shellfishing.

DEM monitors the water quality every month, taking water samples from more than 20 locations around Greenwich Bay and working with the Rhode Island Department of Health to measure the levels of fecal coliform in the water.

DEM follows the federal standards for shellfishing, the National Shellfish Sanitation Program approved by the federal Food and Drug Administration. Across 15 monthly samples, the geometric mean of fecal coliform cannot exceed more than 14 colony forming units (CFU), and no more than 10% of the samples can exceed 31 CFUs.

Greenwich Bay hasn’t exceeded the geometric mean since 2003, but more than 10% of the samples exceeded 31 CFUs eight times between 2000 and 2011.

After a decade of consistency, Borkman said the DEM felt safe making the upgrade. “Things are getting better there now over the last 10 years,” he said. “But with public health you have to be super cautious, super conservative.”

Many areas of Greenwich Bay still remain closed to shellfishing. Fecal coliform levels at Apponaug Cove, Greenwich Cove, Brushneck and Buttonwoods coves, Baker’s Creek, and other outlying areas remain too high.