3106.1 In any flood hazard area, a permit issued by DOB shall be required for all new construction, substantial improvement, or development. A permit for any development on a development site located wholly or partially inside a flood hazard area will not be issued by DOB unless DOEE has determined that the proposed work conforms to the Floodplain Management Regulations.

3106.2 Permit applicants shall provide the information required by the Floodplain Management Regulations in sufficient detail and clarity to determine whether the following conditions are met:

(a) The proposal is designed and constructed with methods, practices and materials that minimize flood damage and that are in accordance with the Floodplain Management Regulations and the American Society of Civil Engineers Standard 24-14 (ASCE 24), Flood Resistant Design and Construction;

(b) All utilities and facilities, such as sewer, gas, electrical, and water systems, are located and constructed to minimize or eliminate flood damage;

(c) The proposed development provides adequate drainage to reduce exposure to flood hazards;

(d) Any wet-floodproofed enclosure at a new construction or substantial improvement of residential or non-residential structures is:

(1) Used only for parking of vehicles, building access, or storage;

(2) Designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters and is either:

(A) Certified by a District registered professional engineer or architect; or

(B) Meets the construction requirements listed in ASCE 24 related to flood resistance; and

(3) Above grade on at least one side.

3106.3 The applicant shall provide any information or documentation requested by DOEE for DOEE to determine whether the proposed development is a substantial improvement. Required documentation includes estimates of the improvement or

repair costs pursuant to the methodology set forth in the Substantial Improvement/Substantial Damage Desk Reference (FEMA P-758, May 2010).

3106.4 The applicant shall provide the following additional information, as applicable:

(a) Zone A. If the specific regulatory flood elevation for a flood hazard area has not been provided in the FIS and FIRM for a development site located in Zone A, then the applicant shall provide the following for DOEE's review and approval:

(1) Available reports or studies from federal or District agencies or other sources related to flood elevation; or

(2) A new hydrologic and hydraulic (H&H) analysis.

(b) Subdivisions. An applicant for a subdivision (including a new manufactured home park or subdivision, or expansion to an existing manufactured home park or subdivision) of more than five (5) acres in area or with more than fifty (50) lots shall show the flood hazard area boundaries and regulatory flood elevations on the plat submitted in the application.

(c) Conditional Letter of Map Revision (CLOMR). If the project requires a CLOMR, the applicant shall provide DOEE the following documentation prepared by a registered professional engineer for submission to FEMA:

(1) Completed FEMA CLOMR forms available at https://www.fema.gov/;

(2) H&H analyses with any additional information required by FEMA;

(3) A letter of transmittal to FEMA;

(4) Receipt for payment of FEMA's processing fees;

(5) Copies of correspondence and documentation submitted to FEMA in which the applicant addresses any issues and comments on the CLOMR request; and

(6) If FEMA issues a CLOMR, as-built plans showing the site elevations and a FEMA approved Letter of Map Revision (LOMR) prior to the issuance of a Certificate of Occupancy.

(d) Letter of Map Revision (LOMR). If the project requires a LOMR, the

applicant shall provide DOEE the following documentation prepared by a District-registered professional engineer for submission to FEMA:

(1) Completed FEMA LOMR forms available at https://www.fema.gov/;

(2) H&H analyses with any additional information required by FEMA;

(3) A letter of transmittal to FEMA;

(4) Receipt of payment of FEMA's processing fees;

(5) Before FEMA issues a LOMR, copies of correspondence letters and documentations submitted to FEMA in which the applicant addresses any issues and comments on the LOMR request; and

(6) A LOMR approved by FEMA before building permit approval, except DOEE may approve site development permits without a FEMA-approved LOMR if the site development permits are for grading or filling of the site that is necessary to elevate it and remove it from the floodplain as specified in the CLOMR.

(e) Alteration of a watercourse. For development that will alter a watercourse, the applicant shall:

(1) Provide an H&H analysis prepared and sealed by a District-registered professional engineer that demonstrates the flood-carrying capacity of the altered portion of the watercourse will not be decreased; and

(2) Make notifications in accordance with 44 CFR § 60.3(b)(6).

(f) No Adverse Impact. For all development (other than development related to interior work that is not considered substantial improvement, floodplain restoration, water body restoration, elevation of a public roadway located outside of a floodway or a flood hazard area with base flood elevations included in the FIS or on the FIRM but no designated floodways, or flood control governmental projects), an applicant shall:

(1) Submit volumetric calculations prepared and sealed by a District-registered professional engineer or surveyor demonstrating that no net loss of natural floodplain storage will occur, as the volume of the loss of floodwater storage due to filling in the flood hazard area shall be offset by providing an equal volume of flood storage by excavation or

other compensatory measures at or adjacent to the development site outside the footprint of a proposed structure; or

(2) Submit an H&H analysis prepared and sealed by a District-registered professional engineer demonstrating that the cumulative effect of the proposed development, when combined with all other existing and anticipated flood hazard area encroachment, will not increase the base flood elevation on any property not owned by the applicant.

(g) Floodway. For development in a floodway or in riverine flood hazard areas where design flood elevations (DFEs) are specified but floodways have not been designated, other than development related to floodplain restoration, water body restoration, or flood control governmental projects, the applicant shall provide a site plan with an H&H analysis performed in accordance with 44 CFR § 60.3(d)(3) and a No-Rise Certification prepared and sealed by a District-registered professional engineer to demonstrate that the development will not result in any increase in flood levels inside the District during the occurrence of the base flood discharge.

(h) Floodplain Restoration, Waterbody Restoration, or Flood Control Government Projects. For development related to floodplain restoration, waterbody restoration, or flood control, the applicant may, with DOEE approval, increase regulatory flood elevations up to one foot (1 ft.) if the increase in flood elevation is offset by stream or channel improvements which have been approved by DOEE. The applicant shall first provide DOEE a FEMA approved CLOMR (See also §§ 3106.4 (c) and (d)).

(i) Covenants and Agreements. Covenants and agreements shall be recorded before permit issuance, as described in § 3112.

(j) Elevation Certificates. An applicant shall submit an elevation certificate for flood elevations, building elevations, and floodway data as shown on construction drawings. Additional elevation certificates are required during and after construction as specified in § 3108.6.

(k) Floodproofing Certificates. When an applicant seeks to undertake dry floodproofing that is not prohibited by this chapter, the applicant shall submit a floodproofing certificate of flood elevations, building elevations, and floodway data as shown on construction drawings. An additional floodproofing certificate is required after construction as specified in § 3108.7.

(l) Engineered Flood Opening Documentation. For an enclosure below the DFE that complies with the Floodplain Management Regulations through

the use of engineered flood openings, the applicant shall provide a statement by a registered design professional that the design of the openings will provide for equalization of hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwaters. The statement shall be provided to DOB and reviewed and approved by DOEE before the issuance of a certificate of completion or the first certificate of occupancy.

(m) Mechanical, Electrical, and Plumbing. For development that includes mechanical, electrical, and plumbing that is not required to be accompanied by plan designs, DOEE may request that the applicant submit supplemental documentation, such as photographs or work receipts for work performed by a licensed professional, or receive an inspection by DOEE, to verify installation that is in accordance with § 3108.1.-

(n) Removing a Property from the Flood Hazard Area. Requests for removal from the flood hazard areas described in § 3101.2 (c) and (d) shall be accompanied and justified by an H&H analysis that is prepared and sealed by a registered design professional and submitted to DOEE for review.

3106.5 A permit for any development on a development site located wholly or partially inside a flood hazard area will not be issued until the applicant has obtained all legally required District and federal permits, including those required by section 404 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. § 1334.

SOURCE: Final Rulemaking published at 32 DCR 6547, 6558 (November 15, 1985); as amended by Notice of Final Rulemaking published at 57 DCR 10776 (November 19, 2010); as amended by Final Rulemaking published at 72 DCR 006821 (June 20, 2025).