Jurisdictional Change of a Domestic Wastewater Facility

Water Protection Program fact sheet
08/2019
Division of Environmental Quality Director: Ed Galbraith
PUB02691

Introduction
This publication discusses subsurface soil dispersal systems and the basic documentation needed to help determine if converting to a subsurface soil dispersal system would change regulatory jurisdiction.However, this is not intended to address specific design criteria, nor is it meant to answer all possible questions. To better understand jurisdiction for domestic wastewater in the state, review the fact sheet titled Who Regulates Wastewater in Missouri (PUB 1296). As described within that publication, either the Missouri Department of Health and Senior Services or the local on-site wastewater administrative authority has jurisdiction for facilities generating 3,000 gallons per day or less of domestic wastewater and dispersing effluent into a subsurface soil absorption system.

Subsurface soil dispersal systems should be included among alternatives evaluated when faced with new or more stringent effluent limitations. Facilities with flows 3,000 gpd or less proposing to change to a subsurface soil dispersal system will be reviewed on a case-by-case basis to determine if a change in jurisdiction is appropriate.

As defined in 10 CSR 20-2.010(26), domestic wastewater is “…wastewater (i.e., human sewage) originating primarily from the sanitary conveniences of residences, commercial buildings, factories, and institutions, including any water which may have infiltrated the sewers. Domestic wastewater excludes stormwater, animal waste, process waste, and other similar waste.” For the purpose of this publication “wastewater” or “domestic wastewater” shall be defined the same as “sewage” or “domestic sewage.” For the purpose of this publication, the term “septic” will only be used as a component of a system (For example: septic tank or anaerobic treatment).

Facilities utilizing discharging lagoons generating a maximum daily flow of 3,000 gpd or less of domestic wastewater and propose to convert to a no-discharge lagoon, followed by either on-site surface land application, subsurface soil dispersal or is pumped and hauled to a permitted facility, should contact the Missouri Department of Natural Resources for assistance. All single-family lagoons serving only a single-family residence are the jurisdictional responsibility of the Department of Health and Senior Services or the local on-site wastewater administrative authority. All other lagoons are the department’s jurisdiction.

What is Subsurface Soil Dispersal?
Subsurface soil dispersal is the method of distributing effluent uniformly into an unsaturated (vadose) zone within the soil. This method effectively treats and controls bacteria and nutrients, and allows local reuse of the treated water.

Soil Treatment Area Requirements
In Missouri, the minimum soil treatment area required for a subsurface soil dispersal system is based upon the soil and site conditions, and their ability to effectively treat and hydrologically control the effluent. 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 a registered on-site 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.

Note: This calculation is for general discussion purposes only. 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. System operation and maintenance must be addressed as part of the initial planning process.

Basic Documentation Needed for Review
The attached checklist is designed to be a guide to compiling the minimum documentation needed for review. More documentation may be required, depending upon the type of facility, soils, available area, geology and how the system is used. The majority of the information on the checklist should be on file with the continuing authority as part of their records.To help keep this review cost effective, neither the department nor the Department of Health and Senior Services asks 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 DHSS or the local on-site wastewater administrative authority for initial review and determination. If the use of a subsurface soil dispersal system is determined to be a feasible option and the change in jurisdictional authority is appropriate, the facility can begin working with the appropriate permitting authority.

The requirements of the residential housing development rule, 10 CSR 20-6.030(1)(C) 6, shall be considered met, provided that all other requirements of the Missouri Clean Water Law and regulations can be satisfied, including that continuing authority is established in accordance with 10 CSR 20-6.010. If those requirements are met, the facility would be exempt from the residential housing development rule, 10 CSR 20-6.030.

Facility construction may proceed once it receives the appropriate approvals and permits from the appropriate on-site wastewater administrative authority. After construction of the subsurface soil dispersal system and any other improvements to the wastewater treatment system are completed, the following shall be submitted to the department to complete the transition of jurisdiction:

Summary
The department, the Department of Health and Senior Services and local on-site wastewater administrative authorities recognize a subsurface soil dispersal system is 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 handled in such a manner that there is no violation of the Missouri Clean Water Law and its regulations. Please contact the department at 800-361-4827 or the Department of Health and Senior Services at 866-628-9891 for more information.

Checklist
To help the appropriate wastewater administrative authoritydetermine 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. Most of this information should be on file with the current owner and/or continuing authority.More information may be required, depending upon the complexity of the existing domestic wastewater treatment system, soils, landscape and geology.

General Information
Please provide the following:

Note: If written approval is required from the department, as described in 10 CSR 20-6.030, it shall be received before the developer can apply for any on-site wastewater treatment system approvals or permits under 19 CSR 20-3.060 or local ordinances.

Daily Design Flow
Please provide the following:

Current System
Please provide the following:

Proposed System
Please provide the following:

Once the documentation is compiled, copies should be sent to the appropriate wastewater administrative authority for initial review and determination. If it is determined that the use of a subsurface soil dispersal system is a feasible option and a change in jurisdictional authority is appropriate, the facility can begin working with the appropriate permitting authority.

If the change in the method of wastewater treatment requires written approval from the department, to satisfy the residential housing development rule, it shall be received prior to applying for any approvals or permits under 19 CSR 20-3.060 (1)(B) Applicability.

Submitting the items on this checklist does not obligate any of the administrative authorities to approve the use of any subsurface soil dispersal system.