Rules Establishing Minimum Standards Relating to Location, Design, Construction and Maintenance of Onsite Wastewater Treatment Systems


250-RICR-150-10-6 ACTIVE RULE

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6.1Purpose

6.2Authority

6.3Liberal Application

6.4Severability

6.5Applicability

6.6Administrative Findings

6.7Incorporated Materials

6.8Definitions

6.9Prohibitions

6.10Class I, II, III, and IV Licenses

6.11Obtaining a Class I, II, III or IV License

6.12Expiration and Renewal of a Class I, II, III or IV License

6.13Disciplinary Action for Class I, II, III and IV Licensees

6.14Installer's License

6.15Onsite Wastewater Treatment Systems – General

6.16Soil Evaluation

6.17Additional Site Testing

6.18OWTS Applications

6.19Required Content of OWTS Submissions

6.20Applications Involving the DEM Freshwater Wetlands Program and the Coastal Resources Management Council

6.21Subdivisions

6.22Wastewater Flow

6.23Minimum Setback Distances

6.24Subsurface Drains

6.25Building Sewers

6.26Grease Tanks

6.27Septic Tanks

6.28Septic Tank Effluent Pipe

6.29Holding Tanks

6.30Pump Tanks

6.31Pumps

6.32Distribution Boxes

6.33Leachfields

6.34Dispersal Trenches

6.35Concrete Chambers

6.36Pressurized Drainfields

6.37Advanced Pressure Drainfields (APDs)

6.38Low Pressure Pipe (LPP)

6.39Large OWTS Requirements

6.40Alternative Toilets

6.41Alternative or Experimental Technology Approval

6.42Critical Resource Areas – General

6.43Requirements in the Salt Pond and Narrow River Critical Resource Areas

6.44Requirements in Drinking Water Supply Watershed Critical Resource Areas

6.45Nitrogen Loading in Areas of Onsite Drinking Water Wells

6.46Permit Expiration

6.47OWTS Installation

6.48Certificate of Construction

6.49Certificate of Conformance

6.50Permit Suspensions and Revocations

6.51Variance Requests

6.52Variance Review Process

6.53Appeals

6.54Fees

6.55Operation and Maintenance

6.56Removal and Abandonment

6.57Cesspool Phase Out

6.58Guidance Documents

6.59Figure 1: Leachfield Over Restrictive Layer or Bedrock

6.60Figure 2: Minimum Setback Distances in Drinking Water Supply Watershed Critical Resource Areas

6.61Figure 3: Minimum Setback Distances in the Salt Pond and Narrow River Critical Resource Areas

6.62Figure 4: Grease Tanks

6.63Figure 5: Septic Tanks

6.64Figure 6: Septic Tank Riser Detail

6.65Figure 7: Leachfield Construction, Invert of Distribution Lines Below Original Grade

6.66Figure 8: Leachfield Construction, Invert of Distribution Lines Above Original Grade

6.67Figure 9: Leachfield Construction on Sloping Sites

6.68Figure 10: Shallow Concrete Chambers

6.69Figure 11: Category 1 Technology and Pressurized Drainfield Schematic

6.70Figure 12: Category 2 Technology and Pressurized Drainfield Schematic

6.71Figure 13: Demand Dosing Tank with Centrifugal Pump

6.72Figure 14: Demand Dosing Tank with Multi-stage Centrifugal Pump

6.73Figure 15: Timed-dosing Tank with Centrifugal Pump and In-line Screen

6.74Figure 16: Timed-dosing Tank with Centrifugal Pump and Basket Screen

6.75Figure 17: Timed-dosing Tank with Screened Vault and Multi-stage Centrifugal Pump

6.76Figure 18: Above-ground Bottomless Sand Filter (Side View)

6.77Figure 19: In-ground Bottomless Sand Filter (Side View)

6.78Figure 20: Typical Bottomless Sand Filter (Top View)

6.79Figure 21: Side View Detail – Typical Bottomless Sand Filter

6.80Figure 22: Orifice Shield Detail: Note: Shields Shall Be Able to Drain. Details Vary from Manufacturer.

6.81Figure 23: BSF Flushing Valve Choice Detail

6.82Figure 24: PSND Cross Section Details

6.83Figure 25: PSND Cross Section Detail (Long Side)

6.84Figure 26: LPP Details for Regular Trenches (Top and Isometric Views)

6.85Figure 27: LPP Details for Shallow Concrete Chambers (Top and Isometric Views)

6.86Figure 28: South Shore Salt Ponds Critical Resource Area

6.87Figure 29: Narrow River Critical Resource Area

6.88Figure 30: Providence Water Supply Board Drinking Water Supply Watershed

6.89Figure 31: Cumberland, Pawtucket Water Supply Board and Woonsocket Drinking Water Supply Watersheds

6.90Figure 32: Newport, New Shoreham and Stone Bridge Fire District Drinking Water Supply Watersheds

6.91Figure 33: Eleanor Slater/Zambarano Unit, Yawgoog Scout Reservation, and Jamestown Drinking Water Supply Watersheds


Title 250 Department of Environmental Management
Chapter 150 Water Resources
Subchapter 10 Wastewater & Storm Water
Part 6 Rules Establishing Minimum Standards Relating to Location, Design, Construction and Maintenance of Onsite Wastewater Treatment Systems
Type of Filing Amendment
Regulation Status Active
Effective 07/01/2022

Regulation Authority:

R.I. Gen. Laws Chapter 42-17.1 Environmental Management; Chapter 5-56 Installers of Individual Sewage Disposal Systems; Chapter 5-56.1 Designers of Individual Sewage Disposal Systems; Chapter 23-19.5 Percolation Tests and Water Table Elevations; Chapter 23-24.3 Substances or Compounds Used as Sewerage System Cleaners; Chapter 46-13.2 Drilling of Drinking Water Wells
and Chapter 23-19.15 Rhode Island Cesspool Act of 2007

Purpose and Reason:

This rule change is necessary to make the OWTS Rules (250-RICR-150-10-6) consistent with the recently adopted “Rules and Regulations Governing the Administration and Enforcement of the Freshwater Wetlands Act” (Freshwater Wetlands Rules) (250-RICR-150-15-3), which go into effect July 1, 2022. The proposed changes are listed below.

Section 6.8 Definitions

6.8(A)(38) The definition of “freshwater wetland” has been deleted and replaced with the definition from the Freshwater Wetlands Rules. The definition of a freshwater wetland is now limited to the wetland resource itself, which includes, but is not limited to, marshes, swamps, bogs, emergent and submergent plant communities, rivers, streams, ponds, and vernal pools. The definition no longer includes any surrounding regulated area, which was formerly referred to as perimeter wetlands and riverbank wetlands.

6.8(A)(84) “Tributary wetland” has been changed to “tributary freshwater wetland.”

6.8(A)(89) The definition of “watercourse” has been changed as follows:

“Watercourse” means any freshwater wetlands, coastal wetlands as defined in R.I.G.L. 46-23-6-2(iii)(E), river, stream, brook, pond, lake, swamp, marsh, bog, fen, wet meadow, area subject to storm flowage, or any other standing or flowing body of water, including such watercourses that may be affected by the tides.

Section 6.9(F) Prohibitions

The term “jurisdictional area” (as defined in the Freshwater Wetlands Rules) has been added to the prohibition regarding installation of leachfields in areas designated as freshwater wetlands. Adding jurisdictional area here maintains the same approach used in the existing OWTS Rules wherein the definition of a freshwater wetland includes the wetland proper and the surrounding regulated area.

Section 6.16(C)(4)

The phrase “any watercourse, wetlands, or surface water bodies” has been changed to “any watercourse” since the definition of “watercourse” includes wetlands and surface water bodies.

Section 6.19(B)(11)

The phrase “all watercourses, wetlands” has been changed to “all watercourses”.

Section 6.20(A)(1) and (1)(b)

The term “jurisdictional area” (as defined in the Freshwater Wetlands Rules) has been added in both instances to describe the potentially affected area in order to maintain the same approach used in the existing OWTS Rules wherein the definition of a freshwater wetland includes the wetland proper and the surrounding regulated area.

Section 6.20(A)(1)(c) 

The phrase “joint OWTS/Freshwater Wetlands application” has been replaced with “joint OWTS/Freshwater Wetlands Permit application” since “Freshwater Wetlands Permit” is the new name for a specific type of application that is acceptable under the provision for a joint application.

Section 6.20(A)(3)

The phrase “any wetland or watercourse” has been changed to “any watercourse.”

Section 6.23(C)

In the Drinking Water Supply Watershed Critical Resource Area setback table, the term “freshwater” has been added to the terms “adjacent wetlands” and “tributary wetlands.”

Section 6.23(D)

In the Salt Pond and Narrow River Critical Resource Area setback table, the term “freshwater” has been added to “tributary wetlands.”

Section 6.24(A)

“Freshwater” has been added to the reference to the “DEM Wetlands Program.”

Section 6.37(C)(1)(f)

The term “buffer” is incorrectly used here since it now has a specific definition in the Freshwater Wetlands Rules. Buffer is replaced here with “setback.”

Section 6.42(C)(3)

In the description of the drinking water supply critical resources areas, Bristol County Water Authority has been deleted from the list of public water systems with a drinking water supply reservoir because the Kickemuit Reservoir is no longer an active source of supply.

Section 6.51(E)

The phrase “surface waters, wetlands” has been changed to “watercourse.” 

Section 6.51(F)(1)

“Freshwater” has been added to the term “tributary wetlands.”

Section 6.53(F)(3)(c)

“Watercourse” is used to replace “body of water or wetland.”

Section 6.54(B)

In 3 parts of the Fee Table, the phrase “joint OWTS/Freshwater Wetlands application” has been replaced with “joint OWTS/Freshwater Wetlands Permit application” since “Freshwater Wetlands Permit” is the new name for a specific type of application that is acceptable under the provision for a joint application.

Section 6.60 and Section 6.61 (Figures 2 and 3)

The term “buffer” is deleted in the key since it now has a specific definition in the Freshwater Wetlands Rules. 

Section 6.91 Figure 33

Figure 33 has been replaced with a map that no longer includes the Bristol County Water Authority Kickemuit Reservoir.