What is the largest wastewater treatment plant in Rhode Island?

Narragansett Bay Commission Bucklin Point in East Providence (rumford), treating an average of 16.27 MGD under NPDES permit RIR50T002. Cranston Water Pollution Control Facility in Cranston is second at 5.3 MGD.

How much wastewater do Rhode Island’s largest plants treat?

The 14 largest plants treat 40 MGD combined, 100% of the flow reported by all 14 publicly owned plants in Rhode Island.

How is plant size measured?

By reported average daily flow in million gallons per day (MGD) from EPA discharge monitoring reports, the standard measure of a plant’s size. Design capacity, the flow a plant is permitted to treat, is usually higher and is shown on each profile.

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The 14 largest wastewater treatment plants in Rhode Island

Name: Largest wastewater treatment plants in Rhode Island
Creator: Klarifi
License: https://klarifi.io/terms-of-service

Ranked by average flow · 40 MGD combined · 100% of the state's reported flow

Narragansett Bay Commission Bucklin Point in East Providence (rumford) is the largest publicly owned wastewater treatment plant in Rhode Island by reported average flow, treating about 16.27 million gallons per day. The 14 plants below treat 40 MGD between them, 100% of the flow reported by all 14 plants in the state, and serve about 378,973 people. Every plant links to its profile with permit, technology and compliance data.

All plants in Rhode Island →The 100 largest US plants →Rhode Island NPDES permits →

The 14 largest publicly owned wastewater treatment plants in Rhode Island by average flow (MGD), with population served, NPDES permit, expiry, treatment technology and three-year violation count.
#	Facility	City	Avg flow (MGD)	Population	NPDES permit	Expires	Technology	Violations (3y)
1	Narragansett Bay Commission Bucklin Point	East Providence (rumford)	16.27	121,400	RIR50T002	Aug 2029	Clarifiers, Biogas silos	8
2	Cranston Water Pollution Control Facility	Cranston	5.3	73,200	RIL100013	Dec 2030	Clarifiers, Biogas balloons	6
3	Newport Water Pollution Control Facility	Newport	5.3	41,600	RI0100293	May 2020	Clarifiers	24
4	East Providence WWTF	East Providence	4.4	46,100	RI0100048	Sep 2028	Clarifiers, Biogas silos, Biogas balloons	70
5	Bristol Wastewater Treatment Facility	Bristol	2.14	20,700	RI0100005	Mar 2028	Clarifiers, Carrousels / oxidation ditches, Biogas silos	25
6	Westerly Wastewater Treatment Facility	Westerly	1.56	16,500	RI0100064	Sep 2026	Clarifiers, Biogas silos	7
7	Smithfield Wastewater Treatment Plant	Smithfield	1.35	14,000	RI0100251	Jun 2026	Clarifiers	3
8	Warren WWTF	Warren	1.19	8,000	RI0100056	Dec 2030	Clarifiers	56
9	Burrillville Wastewater Treatment Plant	Burrillville	0.66	9,700	RI0100455	Jun 2025	Clarifiers	36
10	East Greenwich WWTF	East Greenwich	0.63	6,000	RI0100030	Sep 2023	Clarifiers	7
11	Quonset Point Wastewater Treatment Facility	North Kingstown	0.41	11,593	RI0100404	Dec 2030	Clarifiers	74
12	Scarborough Wastewater Treatment Facility	Narragansett	0.39	7,300	RI0100188	Sep 2028	Clarifiers, Carrousels / oxidation ditches	113
13	New Shoreham WWTF	New Shoreham	0.17	780	RI0100196	Jun 2029	—	149
14	Jamestown Wastewater Treatment Facility	Jamestown	0.1	2,100	RI0100366	Jun 2029	Clarifiers	112

Largest plants in Rhode Island: questions

Sources and methodology

Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.

Data refreshed September 11, 2026.

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