(1) Humus/Composting Toilets are certified for general use subject to the following conditions:

1. (a) There shall be no liquid wastewater discharge from the humus/composting toilet. If the humus/composting toilet produces a liquid by-product that is not recycled through the toilet, the liquid by-product must be either:

   1. 1. discharged through a greywater system on the facility that includes a septic tank and leaching system; or
   2. 2. removed by a licensed septage hauler and properly disposed.

Any other disposal of a liquid by-product requires specific approval by the Department. (b) If there is a greywater discharge designed in accordance with 310 CMR 15.262 or a discharge from a drain equipped with a garbage grinder from the facility, there shall be a septic tank and a soil absorption system designed in accordance with 310 CMR 15.262(1)(a) and 310 CMR 15.240(4). A filter system specifically approved by the Department for that purpose may be used in place of the septic tank, provided that there is no discharge of garbage grinder waste or of liquid by-product from the composting toilet to the greywater system. For publicly used state and federal facilities at which the only sources of greywater are handwashing sinks, janitorial basins and drinking water fountains, the Department may approve a design flow for the greywater system based on water meter readings from the same or similar facilities with a safety factor to assimilate maximum daily flows. An existing cesspool may serve as a leaching pit for these purposes where:

1. 1. the cesspool is pumped and cleaned when the other components of the system are installed;
2. 2. the bottom of the cesspool does not extend below the high groundwater elevation as determined by a Soil Evaluator in accordance with 310 CMR 15.103(3);
3. 3. the cesspool meets the design criteria of 310 CMR 15.253 (pits, chambers, and galleries) with respect to effective depth, separation between units, and inspection access, or the cesspool is replaced by a precast concrete leaching pit meeting those requirements; and
4. 4. the hydraulic loading requirements of 310 CMR 15.242 (effluent loading rates) are satisfied; and

1. (c) The system shall be designed to store compostable and composted solids for at least two years, unless otherwise approved by the Department. Residuals from the system shall be disposed of either:

   1. a. by burial on-site or in another manner and location approved by the local Approving Authority, covered with a minimum of six inches of clean compacted earth; or
   2. b. by a licensed septage hauler.