Skip to main content Skip to office menu Skip to footer
Capital IconMinnesota Legislature

Office of the Revisor of Statutes


Subpart 1.


New construction, replacement, or existing MSTS designed under this chapter are considered conforming if they meet the requirements of this part. Existing MSTS constructed before February 4, 2008, are considered conforming if they meet the requirements of this part, except for subpart 4, items D and E.

Subp. 2.

Treatment required.

All sewage discharged from a dwelling or other establishment not served by a system issued a permit containing effluent and discharge limits or specific monitoring requirements by the agency must be treated according to local ordinances that comply with this chapter, chapter 7082, and Minnesota Statutes, section 115.55.

Subp. 3.

Public health and safety; imminent threat.


To be in compliance, all MSTS must:


have treatment processes and devices that do not allow sewage or sewage effluent contact with humans, insects, or vermin;


disperse sewage effluent into soil or sand below final grade, with the effluent remaining below final grade;


not discharge to drainage tile, the ground surface, or surface water or back up sewage into dwellings or other establishments;


treat and disperse sewage effluent in a safe manner, including protection from physical injury and harm; and


not have received hazardous material.


MSTS must be deemed an imminent threat to public health or safety for noncompliance with item A and any other condition that poses an imminent threat as determined by a qualified employee MSTS inspector or licensed MSTS inspection business.

Subp. 4.

Groundwater protection.

To be in compliance, all MSTS must:


meet the requirements of part 7080.1500, subpart 4, item D;


not be seepage pits, cesspools, drywells, leaching pits, sewage tanks, and treatment vessels that observably leak below the designated operating depth;


not allow viable fecal organisms to contaminate underground waters or zones of seasonal saturation;


employ nitrogen reduction processes that reduce nitrogen contribution to groundwater as determined in subitem (1) or (2):


if the discharge from an MSTS will impact water quality of an aquifer, as defined in part 4725.0100, subpart 21, the effluent from an MSTS, in combination with the effective recharge to the groundwater, must not exceed a concentration of total nitrogen greater than 10 mg/l at the property boundary or nearest receptor, whichever is closest; and


if the discharge from an MSTS will not impact water quality of an aquifer, as defined in part 4725.0100, subpart 21, best management practices developed by the commissioner to mitigate water quality impacts to groundwater must be employed; and


not exceed a groundwater discharge of phosphorus to a surface water that exceeds the phosphorus standard to the receiving water.

Subp. 5.

Other conformance.

To be in compliance, MSTS must meet the requirements of items A and B.


All methods and devices used to treat and disperse sewage must be designed to conform to all applicable federal, state, and local regulations.


Systems no longer in use must be abandoned according to part 7080.2500.

Subp. 6.

System operation.

To be in compliance, an MSTS must meet performance standards and be operated and managed according to its operating permit and management plan, as described in part 7081.0290. To be in compliance, an MSTS designed before February 4, 2008, must be operated according to applicable requirements of part 7080.2450.

Subp. 7.

Compliance criteria for systems receiving replacement components.

Components of existing MSTS that cause noncompliance must be repaired or replaced. The repaired or replacement components must meet technical standards and criteria in parts 7081.0110 to 7081.0280. The remaining components of the existing system must comply with subparts 2 to 5, including subpart 4, item D, if constructed after February 4, 2008.

Subp. 8.

Upgrade requirements.


MSTS in compliance with this part shall be issued a certificate of compliance. Systems found not in compliance shall be issued a notice of noncompliance.


MSTS issued a notice of noncompliance based on criteria in subpart 3 shall be repaired or replaced within ten months or as directed by Minnesota Statutes, chapter 145A, whichever is most restrictive.


MSTS issued a notice of noncompliance based on criteria in subpart 4 or 5 shall be repaired or replaced according to local ordinance requirements.


Systems issued a notice of noncompliance based on criteria in subpart 6 must immediately be maintained, monitored, or managed according to the operating permit.

Statutory Authority:

MS s 115.03; 115.55


32 SR 1400; 35 SR 1353

Published Electronically:

March 11, 2011

Official Publication of the State of Minnesota
Revisor of Statutes