531 STORMWATER MANAGEMENT: CERTIFICATION OF STORMWATER RETENTION CREDITS

531.1 Only the Department shall certify a Stormwater Retention Credit (SRC), and no SRC shall be valid and usable for the purposes of this chapter unless the Department certifies it.

531.2 The Department shall:

1. (a) Certify one (1) SRC for one (1) gallon of retention capacity per year in a Best Management Practice (BMP) or land cover change that meets the eligibility requirements of this section;
2. (b) Assign a unique serial number to each SRC; and
3. (c) Retain and track information about each SRC, including final sale price.

531.3 A person is eligible to apply to certify an SRC if they are one (1) of the following:

1. (a) The owner of the property where the BMP or land cover change is installed or their agent; or
2. (b) The person the property owner has designated to become the owner of the SRC that would be certified.

531.4 For a major regulated project, a person shall file the first complete application to certify SRCs no later than three (3) years after the date the Department has:

1. (a) Completed a final construction inspection; or
2. (b) If no final construction inspection was required, determined the installation of the BMP or land cover change was completed.

531.5 For a major regulated project for which SRCs have previously been certified, a person shall file any subsequent complete application to certify additional SRCs:

1. (a) No later than three (3) years after the end of the preceding SRC certification period the Department approved; and
2. (b) No earlier than three (3) months before the end of the current certification period the Department approved.

531.6 For a project that is not a major regulated project, a person shall file a complete application to certify SRCs as follows:

(a) For the first certification period:

(1) On or before July 30, 2020, if the BMP or land cover change was installed before July 1, 2013; or

(2) At any time after completing construction if the BMP or land cover change was installed on or after July 1, 2013; and

(b) For a subsequent certification period, no earlier than three (3) months before the end of the current certification period the Department approved.

531.7 A BMP or land cover change is eligible to generate an SRC if:

(a) Design, installation, and operation comply with a Department-approved Stormwater Management Plan (SWMP);

(b) A professional engineer licensed in the District of Columbia certified an as-built SWMP that meets the requirements of this chapter and includes the areas that drain to the BMP or land cover change;

(c) The Department approved a final construction inspection; and

(d) All BMPs included in the approved SWMP passed a Department inspection within six (6) months before the date the applicant submitted the application to certify SRCs.

531.8 A gallon of retention capacity in a BMP or land cover change is eligible to generate an SRC if it is from the portion of the retention capacity that:

(a) Is not installed to comply with a stormwater management requirement of a statute, regulation, or court order, including:

(1) A Watershed Implementation Plan established under a Total Maximum Daily Load for the Chesapeake Bay; or

(2) A court-approved consent decree, including court-approved modifications, for reducing Combined Sewer Overflows (CSOs) in the District of Columbia, except that retention capacity installed on an experimental basis as a requirement of the consent decree shall be eligible if a subsequent modification of the consent decree ends the requirement to maintain that retention capacity;

(b) Does not exceed the SRC ceiling as defined in § 599; and

(c) Exceeds:

(1) The Stormwater Retention Volume (SWRv) and Water Quality Treatment Volume (WQTv), if the SRC is generated by a major regulated project;

(2) Pre-project retention, if the SRC is not generated by a major regulated project; and

(3) Water quality treatment requirements of this chapter that were in effect before July 19, 2013, if the SRC is generated by any project approved under those requirements.

531.9 The Department shall not approve an incomplete application for SRC certification.

531.10 A complete application for SRC certification shall consist of:

(a) A completed application form submitted in the Department's submittal database;

(b) An executed maintenance contract or a signed promise to follow a maintenance plan that:

(1) Complies with the Department-approved SWMP and the specifications described in the Department's Stormwater Management Guidebook (SWMG); and

(2) Is for the period of time for which the certification of the SRC is requested;

(c) Documentation that the maintenance provider has the expertise and capacity to provide required maintenance for the period of SRC certification;

(d) A signed promise from the owner of the property on which the BMP or land cover is located to notify the Department if the property is sold or otherwise transferred to another person during the period for which SRCs are certified; and

(e) Any other documentation the Department requires to determine that the eligibility requirements in this chapter are satisfied.

531.11 If the Department determines that a complete application meets the eligibility requirements in this chapter, it shall certify up to three (3) years' worth of SRCs for each gallon of SRC-eligible retention capacity.531.12 The Department shall not certify an SRC for:- (a) Ineligible retention capacity;

- (b) A period that begins earlier than the date of the submittal of a complete application; or

- (c) Any overlapping period in which the Department has already certified an SRC for the same retention capacity.531.13 The Department may waive submittal of any documentation required for a complete application if that documentation is on file with the Department and reflects current conditions, except that the Department shall not waive submittal of a current maintenance agreement or maintenance contract for the BMP or land cover change.531.14 The Department may conduct inspections of a BMP or land cover before and after certification of an SRC.531.15 The Department may refuse to certify an SRC for a person who is currently out of compliance with:- (a) Any Off-Site Retention Volume (Offv) requirement; or

- (b) Any requirement to maintain a BMP or land cover.531.16 A property owner or their agent may propose to aggregate retention from multiple small sites that would not otherwise trigger a stormwater management performance requirement in this chapter by submitting a single SWMP that:- (a) Specifies a common design for multiple BMPs of the same type(s);

- (b) Specifies well-defined technical criteria for location and placement of each BMP;

- (c) Specifies how each BMP will be constructed, operated, and maintained;

- (d) Demonstrates the technical capacity to locate, design, install, and maintain each BMP; and

(e) Demonstrates compliance with the requirements of this chapter.

SOURCE: Final Rulemaking published at 35 DCR 21 (January 1, 1988); as amended by Final Rulemaking published at 60 DCR 10640 (July 19, 2013); as amended by Final Rulemaking published at 67 DCR 818 (January 31, 2020); as amended by Final Rulemaking published at 72 DCR 012101 (October 31, 2025).