Who Regulates Domestic Wastewater in Missouri?

Water Protection Program fact sheet
04/2013
Division of Environmental Quality Director: Ed Galbraith
PUB1296

A common question heard at the Department of Natural Resources is “Who regulates domestic wastewater in Missouri?” The answer is different state and local agencies have responsibility for regulating domestic wastewater including on-site wastewater treatment systems, commonly known as septic systems, and there is a clear line between them. This fact sheet is to help explain who has jurisdictional responsibility for domestic wastewater including septic systems in Missouri.

As stated in Section 701.025 (12), RSMo, Definitions, domestic sewage is defined as “…Human excreta and wastewater, including bath and toilet waste, residential laundry waste, residential kitchen waste and other similar waste from household or establishment appurtenances.”

Missouri Department of Natural Resources

The department is responsible for approving the method of domestic wastewater treatment in new residential housing developments (subdivisions) with seven or more lots where each of the lots is less than five acres in size and propose to use on-site wastewater treatment systems. Department approval is also required for any expansion of an existing subdivision by three or more lots where each of those lots is less than five acres in size.

The department is also responsible for approving the method of domestic wastewater treatment in multiple family housing developments with seven or more units or any expansion of three or more units of an existing development or complex that discharges into subsurface soil absorption systems with sewage flows less than or equal to 3,000 gallons per day. Multiple family housing developments include duplexes, quadplexes, motels, hotels, apartments, RV campgrounds and trailer parks.

After the department has given written approval for the method of wastewater treatment in a residential housing development, it then becomes the Department of Health and Senior Services or local administrative authority’s jurisdiction to issue the construction permit for the specific wastewater treatment system.

The department is responsible for multiple family residences, restaurants and commercial facilities when their domestic wastewater flows are less than or equal to 3,000 gallons per day and do not discharge into subsurface soil absorption systems (e.g. lagoon or any other discharging system). This is done through a construction and operating permit process, with possible exemptions for some non-discharging lagoons.

Finally, the department also regulates all domestic wastewater flows greater than 3,000 gallons per day and all industrial waste flows, which is anything not defined as domestic wastewater.

Related fact sheets and other resources describing permitting, approvals and exemptions are listed at the end of this fact sheet.

Department of Health and Senior Services or Local Administrative Authority

The Department of Health and Senior Services or local administrative authority, commonly the county health department, has responsibility for domestic wastewater generated by single family residences that discharge into a on-site wastewater treatment (septic) system, single family lagoon (one house – one lagoon) or a holding tank.

They also regulate multiple-family residences, restaurants and commercial facilities when their domestic wastewater flows are less than or equal to 3,000 gallons per day and discharge into on-site wastewater treatment systems or a holding tank.

Calculations for gallons per day for on-site wastewater treatment systems will be made according to the Department of Health and Senior Services rule 19 CSR 20-3.060 Minimum Construction Standards for On-Site Sewage Disposal to determine jurisdictional responsibility.

Of the 114 counties in the state, the Department of Health and Senior Services directly administers on-site wastewater regulations in 26 counties. Twenty-seven counties are regarded as contract counties and implement the Department of Health and Senior Services on-site sewage regulation. Those county programs are administered by the local health department. The remaining 61 counties are considered ordinance counties, meaning they have their own on-site sewage regulations, which are as stringent, if not more than, the Department of Health and Senior Services minimum standards.

A copy of the Department of Health and Senior Service’s On-site Sewage regulations and a map indicating who has jurisdiction for on-site sewage systems in your county are available on the web at www.dhss.mo.gov/Onsite/.

MoDNR and DHSS flow chart.

Summary

There is a clear line regarding responsibility of domestic wastewater and on-site wastewater systems in Missouri. Taking time to understand that line will help your project to continue in a timely manner. The department realizes that there is always an infinite number of “What if” questions that this and other fact sheets may not be able to answer. If you have any questions concerning any project please contact the department for assistance.

Related Department of Natural Resources Fact Sheets and Other Resources

For More Information

Missouri Department of Natural Resources
Water Protection Program
P.O. Box 176, Jefferson City, MO 65102-0176
800-361-4827 or 573-751-1300
www.dnr.mo.gov/env/wpp/index.html