Jurisdictional Change of a Domestic Wastewater Facility

Water Protection Program fact sheet
10/2016
Division of Environmental Quality Director: Ed Galbraith
PUB02691

Introduction
With the implementation of more stringent discharge limits on domestic wastewater, the Department of Natural Resources has had a number of facilities proposing subsurface soil dispersal (absorption) systems to eliminate direct discharge and their National Pollutant Discharge Elimination System (NPDES) permit. Subsurface soil dispersal systems should be included among alternatives evaluated when changing the method of disposal from a direct discharging system.  Facilities with flows 3,000 gallons per day (gpd) or less proposing to change to a subsurface soil dispersal system will be reviewed on a case-by-case basis, not only to determine if it is a sustainable solution, but if a change in jurisdiction from the Department of Natural Resources to the Department of Health and Senior Services, Onsite Wastewater Treatment Program or the local onsite wastewater administrative authority (commonly the local health department) is appropriate.

This fact sheet and checklist discuss subsurface soil dispersal systems and the basic documentation needed to help determine if using a subsurface soil dispersal system and changing jurisdiction is a viable option.  This fact sheet is not intended to address specific design criteria nor is it meant to answer all of the “what if” questions. To better understand jurisdiction for domestic wastewater in the state it is recommended to review the Department of Natural Resources fact sheet titled Who Regulates Domestic Wastewater in Missouri – PUB 1296.  As described within that fact sheet, the Department of Health and Senior Services Onsite Wastewater Treatment Program or the local onsite wastewater administrative authority have jurisdiction for facilities that generate 3,000 gallons per day or less of domestic wastewater and disperse effluent into a subsurface soil absorption system.

Domestic wastewater is defined in RSMo 701.025(12) as, “sewage” or “domestic sewage,” “Human excreta and wastewater, including bath and toilet waste, residential laundry waste, residential kitchen waste and other similar waste from household or establishment appurtenances.” For the purpose of jurisdiction anything not defined as domestic wastewater is considered industrial wastewater and is the Department of Natural Resources’ responsibility, regardless of the design flow.

Although, some consider a large-scale subsurface dispersal system nothing more than a “large septic system,” this is a misconception.  For the purpose of this fact sheet the term “septic” will only be used as a component of a system, e.g. septic tank or anaerobic treatment.

Construction and operating permits from the Department of Natural Resources shall be required for all 3,000 gallons per day or less no-discharge lagoons when followed by subsurface soil dispersal system.  This does not apply to a single-family lagoon serving an individual residence on an individual lot since they are the jurisdictional responsibility of the Missouri Department of Health and Senior Services, Onsite Wastewater Treatment Program or the local onsite wastewater administrative authority.

To better understand the 3,000 gallons per day or less no-discharge exemption, the Department of Natural Resources recommends reviewing the fact sheet 3,000 Gallons per Day or Less No-Discharge Domestic Wastewater Lagoon Exemption - PUB1319.

What is Subsurface Soil Dispersal?|
Subsurface soil dispersal is the method of distributing effluent uniformly into an unsaturated (vadose) zone within the soil allowing for the effective treatment and control of bacteria and nutrients along with the local reuse of the treated water.

Soil Treatment Area Requirements
In Missouri the minimum soil treatment area needed is based upon the soil and site conditions and their ability to treat and control the effluent effectively.  This is determined only after a thorough systematic investigation of the soil properties and landscapes of the primary and reserve soil treatment areas.

The minimum square footage for a soil treatment area is calculated by dividing the daily wastewater flow by the soil application (loading) rate assigned by the onsite soil evaluator. Example: 3,000 gpd of domestic wastewater divided by an application rate of 0.20 gpd/sq. ft. equals 15,000 sq. ft. of soil treatment area.  This calculation is for general discussion purposes only. Note the calculated area does not include area for the septic tanks, secondary treatment, pump tanks, trench separation, reserve area, set back distances, or other components of the wastewater collection and treatment system.

Operation and Maintenance
The primary challenge associated with any wastewater treatment system is that they are not always managed by individuals trained for a specific technology.  Long-term operation and maintenance by qualified individuals is imperative to ensure all of the components, including the subsurface soil dispersal system functions optimally for the expected lifespan.  Operation and maintenance must be addressed as part of the initial planning process and not as an afterthought.

Basic Documentation Needed for Review
The Department of Natural Resources and the Department of Health and Senior Services, Onsite Wastewater Treatment Program developed the attached checklist as a guide to compiling the minimum documentation needed for review.  More documentation may be required depending upon the facility, soils, available area, geology, nature of use, etc.  The majority of the information requested on the checklist should be on file with the owner or continuing authority as part of their records.  To help keep this review cost effective, neither department is asking for a preliminary engineering report or a site specific design of the new system at this time.

Once the appropriate documentation is compiled copies should be sent to the Department of Health and Senior Services, Onsite Wastewater Treatment Program or the local onsite wastewater administrative authority for initial review and determination. If it is determined the use of a subsurface soil dispersal system is a feasible option and the change in jurisdictional authority is appropriate then the facility can begin to work with the appropriate permitting authority.  If written approval for the change in the method of wastewater treatment is required from the Department of Natural Resources to satisfy the residential housing development rule, 10 CSR 20-6.030, it shall be received prior to the commencement of construction by any individual and before they apply for any approvals or permits as described within 19 CSR 20-3.060.

Once a facility receives the appropriate approvals and permits from the Department of Health and Senior Services, Onsite Wastewater Treatment Program or local onsite wastewater administrative authority construction may proceed. Once construction of the subsurface soil dispersal system and any other improvements to the wastewater treatment systems is completed the following shall be submitted to the Department of Natural Resources in order to complete the transition of jurisdiction.

Summary
The Department of Natural Resources, Department of Health and Senior Services - Onsite Wastewater Treatment Program and local onsite wastewater administrative authorities all recognize subsurface soil dispersal systems are a sustainable solution that is protective of the public health and the environment.  Regardless of who has jurisdiction of a wastewater treatment facility all wastewater shall be in handled in such a manner that there is no violation of the Missouri Clean Water Law and its regulations.

Please contact the Department of Natural Resources at 800-361-4827 or the Department of Health and Senior Services, Onsite Wastewater Treatment Program at 866-628-9891 for more information.

Checklist

To help the Missouri Department of Health and Senior Services determine if converting a point-discharge domestic wastewater treatment system to one with subsurface soil dispersal is a sustainable solution and if a change in jurisdiction (permitting authority) is necessary, please provide the following information to them.  The majority of the information requested should be on file with the owner or continuing authority as part of their records.  More information may be needed depending upon the complexity of the existing domestic wastewater treatment system, soils, landscape, geology, etc.

General Information

If written approval is required from the Department of Natural Resources as described in the residential housing development rule, 10 CSR 20-6.030, it shall be received prior to the commencement of construction by any individual and before they apply for any onsite wastewater treatment system approvals or permits under 19 CSR 20-3.060 or local ordinances.

Daily Design Flow

Current System

Proposed System

Once the documentation is compiled, copies should be sent to the Department of Health and Senior Services’ Onsite Wastewater Treatment Program or the local onsite wastewater administrative authority for initial review and determination.  If it is determined the use of a subsurface soil dispersal system is a feasible option and a change in jurisdictional authority is appropriate then the facility can begin to work with the appropriate permitting authority.  If written approval for the change in the method of wastewater treatment is required from the Department of Natural Resources to satisfy the residential housing development rule, 10 CSR 20-6.030, it shall be received prior to the commencement of construction by any individual and before they apply for any approvals or permits under 19 CSR 20-3.060 (1)(B) Applicability.

Submitting the items on this checklist does not obligate the Department of Natural Resources, the Department of Health and Senior Services’ Onsite Wastewater Treatment Program or the local onsite wastewater administrative authority to approve the use of any subsurface soil dispersal system.