Section 73.16. Absorption and spray field area requirements

(a) General. Absorption areas and spray fields for single family dwellings not served by a community sewage system shall be designed based on a minimum flow of 400 gpd for all dwellings having three bedrooms or less. The minimum flow of 400 gpd shall be increased by 100 gpd for each bedroom over three.

(b) Absorption areas.

(1) Only the bottom of the aggregate area of the bed or trench shall be used in calculating absorption area requirements.

(2) Absorption area requirements for single family dwellings served by a community sewage system and for apartments or nonresidential establishments served by an individual onlot or community onlot sewage system shall be designed based on flows listed in § 73.17 (relating to sewage flows) for the type of facility to be served.

(3) For nonresidential establishments, a volume of 200 gpd shall be the minimum volume used in calculating the size of the absorption area.

(c) Required absorption area. Table A shall be used in calculating the square footage of absorption area required based on flows determined in subsections (a) and (b). Table A includes allowances for garbage grinders, automatic washing machines or dishwashers and water softeners.

(d) Substitute. When a substitute for aggregate, such as a leaching chamber, large diameter pipe, or other material or device, is used in the absorption area, subsection (b)(1) applies.