250 R.I. Code R. 250-RICR-150-10-6.39

Current through December 26, 2024

Section 250-RICR-150-10-6.39 - Large OWTS Requirements

A. Applicability - Large OWTSs defined below shall comply with all other applicable provisions of these Rules in addition to the requirements in this § 6.36 of this Part. A large OWTS shall be any OWTS designed, installed or operated that meets any of the criteria in §§ 6.39(A)(1) through (4) of this Part below.

1. Any single OWTS designed to treat five thousand (5,000) gallons or more per day;

2. Multiple OWTSs for any project on one (1) or more parcels of land, excluding residential subdivisions, where the total design flow for the project is five thousand (5,000) gallons or more per day;

3. Multiple OWTSs serving more than one (1) unit in a residential subdivision provided that the total design flow of these OWTSs, each serving more than one (1) unit, is five thousand (5,000) gallons or more per day; or

4. Proposed OWTSs and existing OWTSs on the parcel that will result in a total design flow for the parcel exceeding five thousand (5,000) gallons per day.

B. Application Requirements - All submittals for OWTSs meeting the definitions in § 6.39(A) of this Part shall include the following:

1. Notice Requirements: Each application for a large OWTS shall be accompanied by a list identifying the names and addresses of the local building official, the water supply agency whose water supply is drawn from the watershed or wellhead protection area wherein the property is located, if applicable, all property owners within four hundred feet (400') of any component of the proposed OWTS, and all abutting property owners.

a. Upon application, the applicant shall notify each person identified in § 6.39(B)(1) of this Part above, of the application by certified mail, return receipt requested.

b. Each notice shall substantially conform to a form to be provided by the Director and shall include the application number and a certificate of service.

c. The applicant shall clearly mark each return receipt with the application number and the words "5,000 Gallon OWTS."

d. All persons subject to the notice shall be permitted twenty (20) days from the date specified in the certificates of service within which to submit written comments or information bearing upon the subject application.

e. All timely submitted comments or information bearing upon the subject application and relating to the intent and purpose of these Rules shall be considered by the OWTS Program staff as part of their review of the application.

f. When all certified receipts have been returned to the applicant, copies of each notice, accompanied by the appropriate certified receipt, shall be filed with the OWTS Program along with a letter requesting that the application be reviewed for final determination.

g. If a correctly addressed, certified notice is returned to the applicant, the applicant may submit the returned envelope and certified receipt, unopened, along with the other return receipts as proof of the applicant's good faith attempt to serve the notice.

2. Soil evaluation, where required by § 6.16 of this Part;

3. Description of the OWTS and the treatment objectives;

4. Characteristics of the wastewater;

5. Groundwater mounding calculations for any of the component leachfields that are sized for a design flow of five thousand (5,000) gallons per day or greater;

6. Impact analysis in accordance with § 6.39(C) of this Part where the groundwater is classified GA or GAA in accordance with Subchapter 05 Part 3 of this Chapter, Groundwater Quality Rules;

7. Construction materials;

8. Schedule for phased development if applicable; and

9. Plan for operation and maintenance of the OWTS including qualifications of those responsible for maintenance and long-term agreements for maintenance. Such plan shall specify frequency of monitoring and performance inspections and shall include routine maintenance logs needed for proper operation of the OWTS.

C. Impact Analysis - Applicants shall be required to demonstrate that the proposed disposal site is capable of accepting, treating and transmitting effluent at the proposed application rate without adverse impact to surface water or groundwater. Such analysis shall include, but not necessarily be limited to:

1. Surface Water: Applicants shall submit an evaluation of the effect of estimated pollutant loading to surface waters; and

2. Groundwater: Applicants shall conduct modeling of nitrate concentrations in groundwater downgradient of the OWTS at any compliance point defined as the property boundary, drinking water well, or other sensitive receptor as determined by the Director. This compliance point may extend downgradient beyond the applicant's property line if the adjacent property is designated as a groundwater discharge zone in accordance with Subchapter 05 Part 3 of this Chapter, Groundwater Quality Rules. The nitrate concentration modeling shall be done in accordance with the following:

a. For a single OWTS designed to treat five thousand (5,000) gallons or more per day (§ 6.39(A)(1) of this Part), the applicant shall conduct a nitrate impact analysis that models a contaminant plume emanating from the OWTS;

b. For large OWTS defined pursuant to §§ 6.39(A)(2), (3), or (4) of this Part where one (1) or more of the OWTSs is designed to treat one thousand (1,000) gallons or more per day but less than five thousand (5,000) gallons per day, the nitrate impact analysis may use the entire project site for nitrate dilution modeling unless the Director requires a nitrate impact analysis that models a contaminant plume emanating from any of the OWTSs; or

c. For large OWTS defined pursuant to §§ 6.39(A)(2), (3), (4) of this Part where all of the OWTSs are designed to treat less than one thousand (1,000) gallons per day, the nitrate impact analysis may utilize the entire project site for nitrate dilution modeling.

D. Groundwater Monitoring - Groundwater monitoring for nitrate and other possible contaminants, at a frequency to be determined by the Director, may be a required condition of the permit approval. Pursuant to Subchapter 05 Part 3 of this Chapter, Groundwater Quality Rules, the Department may require that actions be taken by the applicant when concentrations of nitrate in the groundwater at the point of compliance exceed the preventive action limit of five (5) mg/l.

250 R.I. Code R. 250-RICR-150-10-6.39

Amended effective 11/25/2018
Amended effective 12/28/2021
Amended effective 7/1/2022