Composting Toilet Regulations

(And why most home-built composting toilets are non-permitted)

(Page updated 6/19/07)

For additional information, see our other web pages on composting toilets:

-Composting Toilets
-Bucket-to-Barrel Composting Toilet
-Barrel Composting Toilet


This page addresses the issues that regulators are concerned with, the reasons why they're concerned with them and how this pertains to permitting of home-built composting toilets (which I will refer to as "non-proprietary" composting toilets).  Much of what follows is based on my familiarity with the regulations for the state of Arizona, but the issues are generally applicable from state to state.  In 2005 the Arizona Department of Environmental Quality rewrote the Arizona state regulations for on-site wastewater permits, which included the regulations pertaining to composting toilets.  I was involved in that process as a representative of an ad hoc group of composting toilet advocates.   

First, a brief overview of composting toilet regulations in the U.S.:  Regulations pertaining to composting toilets are formulated on a state by state basis, and thus vary from state to state.  The responsibility for enforcing those regulations, issuing permits, inspecting installations, etc. may be carried out at either the state level, usually by the state department of environmental quality, or at the county or municipal level.  Counties and municipalities may add more stringent regulations, but cannot have regulations less stringent than those established by the state (in either case, they typically must be granted permission to do so by the state). 

In writing regulations for composting toilets, regulators are concerned with a variety of issues including protection of public health and environmental health, liability, consistency with other rules, public acceptance, etc.  These concerns are reflected in regulations that address virtually all aspects of composting toilet design.  Here is a brief look at the primary issues covered by regulations:

--Disease vector control: Vectors are disease-spreading animals such as rodents and flying insects.  Regulations may require animal-proof construction and the use of insect and rodent-proof screens at all openings into the composting chamber.  

--Prevention of groundwater contamination: Groundwater contamination can lead to contamination of drinking water supplies and hence to illness. The contaminants that regulators are most concerned with are pathogens (disease-causing organisms) and nitrogen. The reasons for keeping pathogens from contaminating groundwater are obvious. Nitrogen, which is present in human waste, can also lead to illness if present in sufficient concentrations.  Regulations may require that all contaminants be contained within the toilet or disposed of into an approved wastewater system such as a septic system, or municipal sewage system.    

--Construction material characteristics: Regulators want to be sure that the materials the toilet is constructed of are durable and corrosion resistant and the regulations may specify such.  In addition, they may require the use of manufactured materials such as pipe, etc. for which there is engineering documentation. 

--Toilet capacity:  Composting toilets must be appropriately sized for the intended number of users.  Regulations usually require documentation of the design capacity of the toilet, in terms of the number of people per day a particular design can accommodate.  The calculations used to arrive at that number may also be required. 

--Composting environment: Effective composting is dependent on an adequate mix of air, moisture and appropriate  temperature.  Regulations may require documentation of how these variables are controlled.         

--Disposal or use of end product: The concern with finished compost is that it may not be entirely pathogen free.  Some jurisdictions require that it be disposed of in a licensed waste system.  Others allow its use as mulch around bushes, trees, or non-food producing plants. 

--Safety and ease of use: Although not usually addressed specifically, regulators typically reserve the right to make a subjective determination regarding whether the the ease of use and maintenance of a particular toilet design is reasonable or not.

--Wastewater disposal: Regulators are also concerned with how the non-toilet "wastewater" flow will be processed.  That includes water from lavatory sink, shower, bathtub, washing machine, etc (graywater), as well as water from kitchen sink and dishwasher (blackwater).  Typically, regulations specify that these sources must flow to a septic or other permitted system, although some states allow the septic to be downsized to reflect a reduced wastewater flow. In Arizona, residential graywater may be reused onsite without issuance of a permit (13 "Best Management Practices" must be followed). However, a permitted system sized to handle the entire wastewater flow is required as a backup in case of graywater system failure.    

--Certification: Determining that a particular composting toilet design meets or exceeds regulations is a responsibility that regulators typically avoid.  Instead, they require that composting toilets be certified by a recognized testing and certification institution such as the National Sanitation Foundation (NSF) or the Canadian Standards Association (CSA).  

From the state's perspective, product testing by a certification institution simplifies and facilitates their approval process, insures that only safe designs are permitted and also helps the state to avoid liability issues.  Unfortunately, certification is an expensive process, costing many thousands of dollars, and is only practical for manufacturers selling large numbers of toilets. 

A related issue that concerns regulators is what happens when a residence with an alternative system such as a composting toilet is sold to another person who may not have the original owners interest in or commitment to it.  Will the new owner use the system correctly? If not, will it become a public health problem? Although this is not an issue that is necessarily addressed in regulations, it is one of the reasons why regulators are more comfortable with certified systems that come with owner's manuals that can be passed on.

Editorial comment: Most people would agree that, in general, these regulatory considerations are reasonable safeguards of public and environmental health. Nonetheless, in my experience, many people who use composting toilets and graywater have non-permitted systems. Ironically, these are often people who are very concerned with living in a safe, sustainable and environmentally responsible way. They desire simple, low-cost, water conserving and environmentally sound technology that safely processes and recycles all waste onsite. Unfortunately, composting toilet designs that are certified and thus can be permitted are often complicated and expensive.  Some feature heating elements that consume copious amounts of electricity, and some don't work as well as advertised. Consequently, many people decide on a non-proprietary system. Most of them would prefer that it be permitted, but are discouraged when they discover that it is unlikely to be approved, that the filing fee for the permit is non-refundable, and that they'll be required to have an expensive, professionally installed septic system for the rest of the household wastewater.

At this point, many of these folks begin to explore ways of flying below the regulatory radar. Those who already have a permitted system such as septic or a municipal sewer hookup may decide to install a non-proprietary composting toilet and graywater system of their own design.  The system may not be legal, but if the neighbors don't complain, this approach often works for them.  

Others avoid the permitting process altogether. This leads to feeling something like a fugitive, wondering if and when the local health authority will discover the practice, shut down the system and levy fines. 

Fortunately, a few states are moving in a more constructive direction in regard to developing composting toilet and graywater regulations and permitting processes that encourage compliance among those who wish to live in a simpler and more environmentally integrated way. Nonetheless, there is still a long way to go. Meanwhile, the cause of developing more favorable regulations will be furthered if those using non-proprietary, non-permitted systems become more familiar with the environmental and public health issues involved and endeavor to develop systems and practices that address these issues. In so doing we can begin to challenge and change the regulatory climate in ways that may eventually allow us to legally live in the environmentally responsible way that we desire.

We hope these web pages are a small step in that direction.


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