Md. Code, Environment § 9-1112

(a) In this section:

(1) “Graywater” means used, untreated water generated by the use of and collected from:

(i) A shower;

(ii) A bathtub; or

(iii) A lavatory sink; and

(2) “Graywater” does not include water from:

(i) A toilet;

(ii) A kitchen sink; or

(iii) A dishwashing machine.

(b) (1) Subject to paragraph (2) of this subsection, and following the adoption of regulations as required by subsection (c) of this section, a person may use graywater for residential purposes including:

(i) Household gardening;

(ii) Composting;

(iii) Lawn watering;

(iv) Landscape irrigation; or

(v) Flushing of a conventional toilet or urinal.

(2) A person may use graywater if the use is permitted under regulations required by subsection (c) of this section, and:

(i) The graywater originates from a residence on the site on which the graywater is to be applied;

(ii) The graywater is contained in a storage tank that is located on the site on which the graywater is to be applied;

(iii) Human contact with graywater and soil irrigated by graywater is avoided;

(iv) Surface application of graywater is not used for irrigation of food plants that have an edible portion that comes in direct contact with graywater;

(v) The graywater does not contain hazardous chemicals derived from any activity, including:

1. Cleaning motor vehicle parts;

2. Washing greasy or oily rags; or

3. Disposing of waste solutions from home photo lab activities or similar hobbyist or home occupational activities;

(vi) The application of graywater is managed to minimize standing water on the surface of the ground;

(vii) The graywater system is constructed to provide for overflow into a sewerage system or an on–site sewage disposal system;

(viii) For a graywater storage tank located outdoors, the graywater storage tank is covered to restrict access and to eliminate habitat for mosquitoes and other vectors;

(ix) The graywater system is located outside the 100–year floodplain;

(x) The graywater system is operated to maintain a minimum vertical separation of at least 5 feet from the point of graywater application to the top of the seasonally high groundwater table;

(xi) Any pressure piping used in a graywater system that may be susceptible to cross connection with a potable water system clearly indicates that the piping does not carry potable water;

(xii) Graywater applied by surface irrigation does not contain water used to wash diapers or similarly soiled or infectious garments;

(xiii) Surface irrigation by graywater is conducted only by flood irrigation or drip irrigation if there is adequate irrigation area;

(xiv) The graywater is not sprayed; and

(xv) The graywater does not run off or pond on–site;

(xvi) The graywater does not create nuisance conditions; and

(xvii) The graywater use is in accordance with any applicable State and local laws or regulations, including State and local plumbing codes.

(c) The Department shall adopt regulations to implement the provisions of this section.