Composting toilets were originally used commercially in Sweden, and they have been commonly used in the United States for at least 30 years, according to the Environmental Protection Agency. They are an alternative to traditional sewer systems, requiring little water and solving environmental problems, particularly in flood-prone areas. Some states specifically allow -- even encourage -- composting toilets. Before installing one, call your health department to check on specific local and state regulations.
Massachusetts allows composting toilets "for remedial use and also certifies them for general use in new residential construction where a system in full compliance with Title 5 could otherwise be installed," according to "Using Composting Toilets and Greywater Systems in Massachusetts." The local board of health and the Board of Registration of Plumbers and Gas Fitters must approve the unit. Your local plumbing inspector must sign off on the installation of indoor fixtures.
Arkansas allows composting toilets approved by public health and safety company NSF International. According to the Arkansas Department of Health, approved composting toilets include Clivus Multrum models 08, 08-0A, 08-A,202 and 205; and Sun-Mar Biological Composting Toilet and Sun-Mar-XL. When you apply for approval of a composting toilet, you also must have a plan for how to dispose of your home's graywater.
Colorado defines composting toilets as "unit(s) which consist of a toilet seat and cover over a riser which connects to a compartment or a vault that contains or will receive composting materials sufficient to reduce waste by aerobic decomposition." When installing your toilet, you must ensure the receptacle's volume is sufficient for the number of people served, and your composting toilet must be NSF-approved.
Florida regulations state that composting toilets are allowed, even encouraged, in flood-prone areas. You must receive approval by the DOH county health department, and composting toilets must be in compliance with NSF Standard 41.
Idaho defines composting toilets as "toilets within the dwelling that store and treat non-water carried human urine and feces and small amounts of household garbage by bacterial decomposition." You may have them in your home if you have water under pressure, "with the understanding that a public sewer or another acceptable method of on-site disposal is available," according to state regulations. You must receive permission from the Idaho Health Department before installation.
Pennsylvania allows composting toilets "that bear the seal of the NSF indicating testing and approval by that agency under Standard No. 41," according to state regulations. Before installation, you must provide an on-lot sewage system or other approved method of sewage disposal to treat excess liquid or washwater. If you are installing a composting toilet in an existing residence where you are not altering the on-lot system, you do not need a permit.
In Tennessee, you may use composting toilets listed as one of the NSF-Certified Wastewater Recycle/Reuse and Water Conservation Devices. You may not use a composting toilet if running water is available unless you have an acceptable means to dispose of wastewater.
Illinois requires composting toilets to be "designed in accordance with the manufacturer's recommendation to serve the anticipated number of persons." Disposal of the contents can be done through a municipal sanitary sewer system, to sludge lagoons or drying beds, to an incinerator device or to a sanitary landfill, state regulations say. All composting toilets must meet NSF Standard 41 and bear the NSF Seal.
In South Carolina, state regulations say, "Composting toilets may be used in conjunction with an approved septic system, for facilities that are provided with water under pressure."
Oregon defines a composting toilet as "a permanent, sealed, water-impervious toilet receptacle screened from insects, used to receive and store only human wastes, urine and feces, toilet paper and biodegradable garbage, and ventilated to utilize aerobic composting for waste treatment." State regulations state that your toilet must be ventilated, have at least 1 cubic yard capacity for a one- or two-bedroom dwelling, be used only in areas where a graywater disposal system can be installed, and placed in an insulated area to keep a biological balance of the materials. You may place humus from composting toilets around ornamental shrubs, flowers or trees (never around edible vegetation). The humus must be buried under at least 12 inches of soil. Your toilet must be approved by the NSF Standard 41.
Maine requires that "the minimum interior volume of a composting toilet shall be large enough to allow complete stabilization of all wastes when the toilet is used continuously at its proposed usage level."