(a) The Director must not issue a building permit for any detached one- or two-family residential building located on a recorded lot smaller than 15,000 square feet, or a permit for any addition to such a residential building that would increase the building lot coverage by more than 400 square feet, unless the plans provide for safe conveyance or control of any increased water runoff, resulting from additional impervious area or any other topographic alteration, that would drain onto any adjacent or nearly private property.
(b) In this Section, approved drainage system means any method of safe conveyance from the property or storage on the property of on-site water runoff at the design rate specified in subsection (c), using one or more of the following methods or devices or any other method or device approved by the Director that would provide equivalent or greater protection of adjacent and nearby properties:
(1) on-site absorption or drainage device, such as rain barrel, cistern with slow release or controlled pump discharge, underground percolation and storage system, rain garden, rooftop garden or detention device, bioretention filter, or vegetation buffer;
(2) existing or new drainage facility, such as drainage interceptor, inlet, trench, permeable paved area, or similar feature;
(3) drainage line, inlet or pipe, or other engineered feature such as a swale or ditch; or
(4) natural topography or buffer area that successfully absorbs water drainage.
(c) Each approved drainage system must be designed to convey or control at least 1.5 inches of rainfall during a 24-hour period.
(d) After the approved drainage system is installed, the permittee must certify to the Director that the system:
(1) has been installed as provided in the plans approved by the Director; and
(2) will convey or control the water runoff specified in subsection (c) without impacting adjacent or nearby private properties.
(e) The permittee and the permittee’s successors in interest must preserve and maintain each approved drainage system to the extent necessary to provide the same level of protection for adjacent and nearby properties. The permittee and the permittee’s successors in interest must obtain the Director’s approval before materially modifying any element of an approved drainage system. The Director may require a permittee to record an easement in the County land records for any approved drainage system to assure the continued preservation and maintenance of that system. (, § 1.)
Editor’s note—2006 L.M.C., ch. 37, § 2, states, in part: County Code Section 8-29B, inserted by Section 1 of this Act, applies to any building for which an application for a building permit is filed on or after that date.
