The following zoning regulations protect solar installations from development that would interfere with their operation.
11 DCMR Subtitle E, Chapter 2

• 206.3
  Any new building, or alteration or addition to an existing building, including a rooftop structure or penthouse (the proposed construction) at the time of application, shall not significantly interfere with the operation of a solar energy system on an abutting property, unless agreed to by the owner of the solar energy system, subject to the following:  
  • (a) “Time of application” shall mean the earlier of either:
    • (1) The Department of Consumer and Regulatory Affairs officially accepts as complete the application for the building permit for the proposed construction; or
    • (2) the Office of Zoning officially accepts as complete an application for zoning relief for the proposed construction;
  • (b) “Solar energy system” shall mean a solar energy system of at least 2kW in size that, at the time of application, is either:
    • (1) Legally permitted, installed, and operating; or
    • (2) Authorized by an issued permit; provided that the permitted solar energy system is operative within six (6) months after the issuance of the solar energy system permit not including grid interconnection delays caused solely by a utility company connecting to the solar energy system;
  • (c) “Significantly interfere” shall mean that the proposed construction increases the shading incident on the solar energy system by more than five percent (5%), as determined by a comparative solar shading study acceptable to the Zoning Administrator; and
  • (d) All applications for the proposed construction, whether for a building permit or for zoning relief, must include one of the following:
    • (1) An affidavit by the applicant stating that there is no solar energy system on an abutting property;
    • (2) A comparative solar shading study that meets the minimum standard established by the Zoning Administrator for the purpose of determining the increased annual incident solar shading by percent; or
    • (3) A written agreement executed by the owner of the impacted solar energy system accepting the interference with the solar energy system. 

• 206.4
  Relief from the requirements of Subtitle E §§ 206.1 and 206.3 may be approved by the Board of Zoning Adjustment as a special exception under Subtitle X, Chapter 9, and subject to the conditions of Subtitle E § 5207.