Composting toilet laws by state
A composting toilet is easy to buy and legal to use. Getting one accepted instead of a septic system for a permitted home is where state and county rules differ.
What to know first
Composting toilet rules sit inside two bodies of regulation. Onsite wastewater rules, run by state environmental or health agencies and often delegated to counties, decide what a home needs instead of a sewer connection. Plumbing codes decide what fixtures a house needs. Where neither mentions waterless toilets, local officials decide case by case, and outcomes vary from county to county.
Even where a state recognizes composting toilets, it almost always still requires a system for graywater from sinks, showers and laundry. The practical benefit is often a smaller drainfield, not the absence of one. Many rules also require a certified unit, typically to NSF/ANSI 41.
Our septic and composting toilet guide explains soil testing, system choices and the questions to ask before you buy. The table below shows who issues septic permits in each state, which is usually the first office to call.
State-by-state table
Filter by status or search for a state. Each summary links to the official source we relied on, and each state name opens the full guide. Statuses describe state-level rules; counties, cities and health districts can add requirements.
50 states
| Alabama | Recognized in state rules | ADPH rules allow composting toilets certified to the appropriate NSF standard. Liquid must go to a public or private sewer, and other household sewage still needs an appropriate onsite sewage system.Ala. Admin. Code r. 420-3-1-.29 (Composting, Incinerating, and Portable Toilets) Source | County health departments under Alabama Department of Public Health rules (Ala. Admin. Code Chapter 420-3-1) |
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| Alaska | Recognized in state rules | DEC states indoor composting and incinerating toilets are not regulated by the onsite wastewater program if wholly contained. Outdoor compost privies need pit privy setbacks, and graywater still requires treatment.Alaska DEC: Onsite Wastewater Systems Installation Manual, Section 1.4.2 Source | Alaska Department of Environmental Conservation (DEC) under 18 AAC 72 |
| Arizona | Case-by-case approval | Composting toilets are covered by ADEQ's Type 4.03 general permit and go through the county-delegated onsite approval. Graywater and other household wastewater still need an approved treatment and disposal arrangement.ADEQ: Type 4 General Permits Source | County environmental health or onsite wastewater offices under delegation from the Arizona Department of Environmental Quality (ADEQ) |
| Arkansas | Recognized in state rules | ADH rules allow pre-manufactured composting or incinerating toilets authorized by the Department and evaluated under NSF Standard 41. All other household wastewater must still go to an approved onsite system.ADH: Rules Pertaining to Onsite Wastewater Systems (2024), Section 9.10 Source | Arkansas Department of Health (ADH) through local health units and authorized agents |
| California | Unclear | The statewide OWTS Policy does not address composting toilets and excludes pit privies and graywater. Acceptance appears to rest with local building and environmental health departments; a wastewater system is still needed.State Water Resources Control Board: 2023 OWTS Policy Source | County or city environmental health agencies under the State Water Resources Control Board OWTS Policy, often through a Regional Board-approved Local Agency Management Program |
| Colorado | Case-by-case approval | Local boards of health may permit composting toilets meeting NSF/ANSI 41. An OWTS is still required for remaining wastewater, with limited size reductions only where no flush toilet exists.5 CCR 1002-43, Section 43.12.E (Incinerating, Composting and Chemical Toilets) Source | Local public health agencies under the Water Quality Control Commission's Regulation 43 (5 CCR 1002-43) |
| Connecticut | Case-by-case approval | Section 19-13-B103f lets the local director of health approve large-capacity or heat-assisted composting toilets, including for owner-occupied single-family homes, but only where the lot tests suitable for a full code-compliant septic system.Public Health Code §§ 19-13-B103a to B103f, On-Site Sewage Disposal Systems and Non-Discharging Toilet Systems (DPH) Source | Local directors of health (town health departments and health districts) under Department of Public Health rules; DPH reviews larger designs and DEEP permits systems over 10,000 gallons per day |
| Delaware | Not addressed statewide | The on-site wastewater regulations reviewed do not specifically address composting toilets. DNREC says greywater use and similar innovative technologies are subject to its review and approval.Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems (DNREC, with exhibits) Source | Delaware Department of Natural Resources and Environmental Control (DNREC), Division of Water, under 7 DE Admin. Code 7101 |
| Florida | Recognized in state rules | Rule 62-6.009 allows waterless, incinerating or composting toilets meeting NSF/ANSI 41 or NSF P157. Graywater still needs an onsite system, though residential drainfield size is reduced 25% when used for all toilet waste.Rule 62-6.009, F.A.C., Alternative Systems (effective June 21, 2022) Source | Florida Department of Environmental Protection, which began direct permitting in transition counties in 2025; county health departments remain the contact in other counties |
| Georgia | Recognized in state rules | The DPH manual allows composting toilets certified to NSF Standard 41. Kitchen, bath and laundry water still needs a septic tank system, but the absorption field may be 35% smaller with low-flow fixtures.Manual for On-Site Sewage Management Systems (Georgia DPH, March 2026), Section D Source | County boards of health (county environmental health offices) under Georgia Department of Public Health Rule 511-3-1 |
| Hawaiʻi | Recognized in state rules | DOH lists composting and incinerator toilets as approved individual wastewater system equipment, but notes they treat toilet waste only. Shower, kitchen and laundry wastewater still requires approved treatment and disposal.Individual Wastewater Systems — Hawaii Department of Health Source | Hawaii Department of Health, Wastewater Branch, statewide under HAR Chapter 11-62 |
| Idaho | Case-by-case approval | IDAPA 58.01.03 lists composting toilets and incinerators as proprietary non-discharging systems that need DEQ design approval, with guidance in the Technical Guidance Manual. Graywater still needs approved disposal.IDAPA 58.01.03, Individual/Subsurface Sewage Disposal Rules, Section 009 Source | Idaho's seven public health districts, under Department of Environmental Quality rules (IDAPA 58.01.03) |
| Illinois | Recognized in state rules | The Private Sewage Disposal Code (77 Ill. Adm. Code 905) lists compost toilets among approved methods for human waste. Sink, shower and laundry water still needs an approved private sewage system.77 Ill. Adm. Code 905.130 Source | Illinois Department of Public Health, with about 90 local health departments reviewing plans by ordinance or as IDPH agents |
| Indiana | Case-by-case approval | IDOH guidance lets the local health officer allow composting or incinerating toilets, preferably NSF/ANSI 41 certified, only when a full 410 IAC 6-8.3 onsite system is also designed and installed.The Use of Composting and Incinerating Toilets in One and Two Family Dwellings Source | Local health departments under Indiana Department of Health rule 410 IAC 6-8.3 |
| Iowa | Not addressed statewide | Iowa's Chapter 69 private sewage rules address vault and portable toilets but were not found to address composting toilets. Approval rests with the county board of health; graywater still needs a permitted system.Chapter 69 — Private Sewage Disposal Systems Source | County boards of health under Iowa DNR rules in 567 IAC Chapter 69 |
| Kansas | Unclear | No Kansas provision recognizing composting toilets was confirmed. Acceptance depends on the county sanitary code, and kitchen, laundry and bath wastewater must still reach an approved onsite system.County Environmental / Sanitary Codes Source | County or local sanitary code authorities, using KDHE Bulletin 4-2 minimum standards |
| Kentucky | Recognized in state rules | 902 KAR 10:085 recognizes approved composting and incinerator toilets in a residence and allows reduced design flows. Graywater still needs a permitted absorption system sized at 55 gallons per day per bedroom.902 KAR 10:085 — Kentucky onsite sewage disposal systems Source | Local health departments, through cabinet-certified inspectors, under 902 KAR 10:085 |
| Louisiana | Unclear | We have not established how the Louisiana Sanitary Code treats composting toilets. Any household wastewater would still need an approved parish health unit system; ask the local sanitarian before relying on one.Onsite Wastewater Program Source | Louisiana Department of Health sanitarians in parish health units |
| Maine | Recognized in state rules | Chapter 241 lists composting toilets as alternative toilets. A permit is required, liquid overflow must go to a disposal field, and grey water still needs a primitive, limited or conventional disposal field.Subsurface Wastewater Disposal Rule, 10-144 CMR 241 (last amended September 23, 2023) Source | Municipal Local Plumbing Inspectors under Maine CDC's Subsurface Wastewater Disposal Rules (10-144 CMR 241); the Department appoints inspectors in unorganized areas |
| Maryland | Case-by-case approval | COMAR 26.04.02 does not name composting toilets. It defines a privy as a receptacle for non-water-carried waste and requires Approving Authority approval of privy location and construction plans.COMAR 26.04.02.08 — Special Methods of Sewage Collection and Disposal Source | County health departments and other local Approving Authorities delegated by the Maryland Department of the Environment under COMAR 26.04.02 |
| Massachusetts | Recognized in state rules | Title 5 certifies humus/composting toilets for general use. New homes must show a full Title 5 system could fit; greywater still needs a septic tank or approved filter and leaching area.310 CMR 15.289 — Humus/Composting Toilets (LII) Source | Local boards of health, administering MassDEP's Title 5 (310 CMR 15.000) |
| Michigan | Unclear | No state rule naming composting toilets was found. Michigan's general outhouse rules require fly-tight receptacles that protect water supplies; acceptance in a dwelling is a local health department decision.Mich. Admin. Code R. 325.421 — Outhouses: Principles (LII) Source | Local (county or district) health departments, with EGLE support and EGLE permits for larger or discharging systems |
| Minnesota | Recognized in state rules | Minn. R. 7080 defines toilet waste treatment devices to include composting toilets. Gray water still needs a gray water system sized at 60 percent of normal flow; toilet waste cannot enter it.Minn. R. chapter 7080 — Individual Subsurface Sewage Treatment Systems Source | Counties, cities and townships under MPCA's SSTS rules (Minn. R. chapters 7080–7083); MPCA permits systems over 10,000 gallons per day |
| Mississippi | Not addressed statewide | No reference to composting or waterless toilets was found in MSDH's on-site wastewater regulations. Any alternative to a standard system would need MSDH acceptance, and household wastewater still needs an approved system.MSDH On-Site Wastewater Regulations (Part 18, Subpart 77) Source | Mississippi State Department of Health, Division of On-Site Wastewater, through county health department environmentalists |
| Missouri | Case-by-case approval | 19 CSR 20-3.060 lists composting toilets as non-ground absorption systems and allows up to 40 percent design-flow reduction for graywater systems. Privies are not accepted for continuously occupied dwellings.19 CSR 20-3 — On-site sewage disposal rules Source | DHSS Onsite Wastewater Program, or a local authority by contract or ordinance; DNR for surface discharge, larger flows and subdivisions |
| Montana | Recognized in state rules | Circular DEQ-4 section 8.5 allows composting toilets as waste segregation, with separate graywater disposal. Units must meet NSF Standard 41 criteria, and a replacement site for a full system is required.Circular DEQ-4: Montana Standards for Subsurface Wastewater Treatment Systems (2023) Source | Local boards of health and county sanitarians under DEQ minimum standards; DEQ reviews subdivisions under the Sanitation in Subdivisions Act |
| Nebraska | Not addressed statewide | Title 124 does not mention composting or waterless toilets. It defines blackwater and graywater and offers a holding-tank general permit, so household wastewater still needs an approved system.Title 124 — Onsite Wastewater Treatment Systems Source | Nebraska Department of Water, Energy, and Environment (DWEE) under Title 124; local governments may add requirements |
| Nevada | Unclear | NAC 444 does not name composting toilets. A toilet not connected to a sewage system is a nonsewered toilet, which may not be used for permanent disposal; alternative systems need health-authority approval.NAC 444.826 — Nonsewered toilets: General requirements Source | Local health authorities or county building departments, such as Southern Nevada Health District, Northern Nevada Public Health and Central Nevada Health District, under NAC 444 |
| New Hampshire | Case-by-case approval | Env-Wq 1000 does not name composting toilets. It allows privies and gray-water mini-dry wells only where there is no running water; other technology needs NHDES innovative/alternative approval under Env-Wq 1024.Env-Wq 1024.01 — Innovative/alternative technology: purpose and applicability Source | New Hampshire Department of Environmental Services (NHDES) Subsurface Systems Bureau |
| New Jersey | Case-by-case approval | N.J.A.C. 7:9A-7.5 lets the board of health approve a greywater system with a waterless toilet, but only after the owner obtains a variance from the UCC plumbing subcode.N.J.A.C. 7:9A-7.5 — Separate disposal of greywater and blackwater Source | Local boards of health for residential systems under 2,000 gallons per day, under N.J.A.C. 7:9A; NJDEP for alternative designs and larger systems |
| New Mexico | Recognized in state rules | 20.7.3.803 NMAC allows composting and incinerating toilets installed under the New Mexico plumbing code and local plumbing authority, but they do not reduce the property's design flow for the wastewater system.Liquid Waste Disposal — 20.7.3 NMAC (20.7.3.803) Source | New Mexico Environment Department field offices under the Liquid Waste Disposal rule (20.7.3 NMAC) |
| New York | Recognized in state rules | Appendix 75-A.10 allows non-waterborne systems. Composters must carry an NSF Standard 41 (or equivalent) label and a warranty of at least five years; sink and shower greywater still needs treatment.10 NYCRR Appendix 75-A.10 — Other systems Source | County or city health departments, or NYSDOH district offices where no local department exists, under 10 NYCRR Appendix 75-A |
| North Carolina | Recognized in state rules | 15A NCAC 18E .1001 allows composting, incinerating and mechanical toilets under the NC Plumbing Code. All other wastewater must go to an approved system, and residuals must be removed by a permitted septage firm.15A NCAC 18E (Wastewater Treatment and Dispersal Systems), Rule .1001 Source | County (local) health departments under the state rules in 15A NCAC 18E, with DPH On-Site Water Protection Branch oversight |
| North Dakota | Case-by-case approval | The private sewage rule (NDAC 62-03.1-03) does not name composting toilets. Without pressurized water, waste may go to approved privies, chemical toilets or other installations acceptable to the administrative authority.NDAC Chapter 62-03.1-03, Private Sewage Disposal Systems Source | Local public health units issue permits; the Department of Environmental Quality licenses installers under NDCC 23.1-07.1 |
| Ohio | Recognized in state rules | OAC 3701-29-17 treats NSF/ANSI 41-certified composting toilets as authorized sewage system components. All other household wastewater must still go to an approved system, though design flow may drop up to 25 percent.Ohio Adm.Code 3701-29-17, Gray water recycling systems and alternative toilets Source | Local boards of health (health districts) under ORC Chapter 3718 and Ohio Department of Health rules in OAC 3701-29 |
| Oklahoma | Not addressed statewide | OAC 252:641 covers septic tanks, aerobic units, dispersal fields and lagoons, with no composting-toilet provision. DEQ says any system outside its rules needs DEQ approval before installation.On-Site Sewage Treatment Systems Source | Oklahoma Department of Environmental Quality, Environmental Complaints and Local Services (ECLS) local offices |
| Oregon | Case-by-case approval | DEQ rules treat toilets with no water connection as nonwater-carried waste facilities. OAR 340-071-0330 requires a letter of authorization or permit from the agent. Graywater still needs lawful disposal.OAR 340-071-0330, Nonwater-Carried Systems Source | Oregon DEQ directly in Curry, Jackson and Josephine counties; contracted county agents elsewhere |
| Pennsylvania | Recognized in state rules | 25 Pa. Code 73.65 recognizes composting toilets bearing the NSF Standard 41 seal. New installations still need an on-lot system or other approved method for washwater, under one permit.25 Pa. Code 73.65, Recycling, incinerating or composting toilet Source | Municipal or local-agency Sewage Enforcement Officers (SEOs) certified under the DEP Act 537 program |
| Rhode Island | Recognized in state rules | OWTS Rule 6.40 allows composting toilets meeting NSF Standard 41. They need a two-year maintenance contract, recorded permit conditions and inspector reports, plus a separate graywater OWTS sized at 60 percent of design flow.250-RICR-150-10-6, OWTS Rules, section 6.40 Source | Rhode Island Department of Environmental Management (DEM), statewide |
| South Carolina | Case-by-case approval | R.61-56 defines composting toilets as nonwater-carried sewage treatment systems. They need an SCDES permit to construct and approval to operate, and a Registered Professional Engineer must design the system.S.C. Code Regs. 61-56.101, Definitions and References Source | South Carolina Department of Environmental Services (SCDES) under Regulation 61-56 |
| South Dakota | Case-by-case approval | ARSD 74:53:01:10 lists composting, incinerating and chemical toilets as unconventional systems where water or electricity is unavailable. Except vault privies, plans must be submitted to DANR for approval as experimental systems.ARSD 74:53:01:10 — Unconventional systems Source | South Dakota DANR under ARSD 74:53:01, with local governments able to regulate more strictly |
| Tennessee | Recognized in state rules | Rule 0400-48-01-.17 allows composting toilets certified to NSF Standard 41. They are not permitted where running water exists unless there is an acceptable means to dispose of wastewater.Tenn. Comp. R. & Regs. 0400-48-01-.17 — Privies and Composting Toilets Source | TDEC Division of Water Resources field offices and contract counties; registered engineers or qualifying soil scientists may use the third-party route |
| Texas | Recognized in state rules | TCEQ rules approve composting toilets tested and certified under NSF/ANSI Standard 41. An approved onsite sewage facility is still required for graywater and all other household wastewater.30 Tex. Admin. Code § 285.34 (Other Requirements) Source | Local authorized agents (often counties) or TCEQ regional offices under TCEQ OSSF rules (30 TAC Chapter 285) |
| Utah | Unclear | We found no composting toilet provisions in the R317-4 sections reviewed. Acceptance appears to depend on the local health department, and graywater still needs an approved disposal method.Utah Admin. Code R317-4-1 (Authority, Purpose, Scope) Source | Local health departments under Division of Water Quality rule R317-4 |
| Vermont | Case-by-case approval | DEC guidance says composting and incinerating toilets require an Agency of Natural Resources permit under the Wastewater System and Potable Water Supply Rules. Removed contents must be disposed of under § 1-929 of the Rules.Composting and Incinerating Toilets Guidance Document (DEC, 2020) Source | Vermont Department of Environmental Conservation (Agency of Natural Resources) regional offices, through the Wastewater System and Potable Water Supply permit |
| Virginia | Recognized in state rules | 12VAC5-610-980 lists composting toilets as nonwater-carried systems if certified to NSF Standard 41. A separate sewage disposal system is still required for wastewater from bathing, laundry, handwashing and cooking.12VAC5-610, Part V, Article 6 — Virginia Administrative Code Source | Local health departments of the Virginia Department of Health, under the Sewage Handling and Disposal Regulations (12VAC5-610) |
| Washington | Recognized in state rules | DOH standards recognize composting, incinerating, vault and pit toilets. Proprietary units must meet NSF/ANSI 41, and where greywater is generated an approved greywater system or sewer is still required.Water Conserving On-Site Wastewater Treatment Systems Department Standards (DOH 337-016) Source | Local health jurisdictions (county or district health officers) under Department of Health rules, chapter 246-272A WAC |
| West Virginia | Recognized in state rules | State sewage rules allow composting toilets meeting NSF Standard 41, but only together with an approved greywater treatment and disposal system. Privies are also addressed, with setback rules.W. Va. Code R. § 64-47-6 Individual sewage systems (Cornell LII) Source | Local health departments under Bureau for Public Health rules (64CSR47 and related sewage rules) |
| Wisconsin | Unclear | Wisconsin has state rules for non-plumbing sanitation systems such as composting toilets and privies. We have not yet reviewed the current text, so confirm requirements with the county. Graywater still needs an approved POWTS.Private Onsite Wastewater Treatment Systems — DSPS Source | Counties or other delegated local agents under Department of Safety and Professional Services POWTS rules (SPS 383) |
| Wyoming | Case-by-case approval | DEQ's Water and Wastewater Program lists incinerating or composting toilets among the systems it assists with and permits. Ask DEQ or the county about design standards and how greywater must be handled.Water and Wastewater Program — Wyoming DEQ Source | Wyoming DEQ in Carbon, Niobrara, Platte and Weston Counties (plus commercial systems in Campbell); county or city-county health departments or other delegated authorities elsewhere |
Checked October 2026. Laws change; open the linked source before relying on a summary. Found an error? Tell us.
Common questions
Are composting toilets legal?
Composting toilets are sold and used in every state, but whether one can replace a septic system for a permitted home is a different question. In our research, 23 states recognize waterless or composting toilets in their onsite or plumbing rules, and 15 handle them through case-by-case approval. The rest do not address them statewide, which leaves the decision to local health and building officials.
Do I still need a septic system with a composting toilet?
Usually, yes. Sinks, showers and laundry produce graywater, and most states require it to go to an approved septic or graywater system. Some states allow a smaller system when toilets are waterless. A health department may also require the home to have space reserved for a conventional system in case the toilet is removed later.
What is NSF/ANSI 41?
NSF/ANSI Standard 41 is the national performance standard for non-liquid saturated treatment systems, which includes composting toilets. Several states and local health departments accept only units certified to it. Site-built composting toilets rarely meet such rules, so check before building one for a permitted home.
Where can I put the compost?
States that regulate composting toilets often set rules for the finished material, such as burial depth, setbacks from wells and water, or a requirement to use it only on non-food plants. Follow the manufacturer’s instructions and any state or county disposal rule.