Minnesota Administrative Rules

7081.0040 STATE REGULATION.

Subpart 1.

Agency regulation.

A.

All MSTS must be designed and operated according to this chapter, except as modified through an ordinance in compliance with chapter 7082 and Minnesota Statutes, section 115.55. All MSTS must be designed, installed, inspected, pumped, and operated by a qualified employee under part 7083.1010 or a licensed business under part 7083.0710. All MSTS must conform to applicable state statutes and rules.

B.

The owner or owners of an SSTS must obtain an SDS permit from the agency according to chapter 7001 when:

(1)

a single proposed or existing soil dispersal area receives a flow greater than 10,000 gallons per day; or

(2)

all proposed and existing SSTS soil dispersal areas that are under common ownership and within one-half mile of each other have a combined flow greater than 10,000 gallons per day. Flow from an SSTS with low impact to potable water is not counted in this subitem.

C.

An SDS permit is required for any subsurface sewage treatment system or group of subsurface sewage treatment systems that the commissioner determines has the potential or an increased potential to cause adverse public health or environmental impacts if not regulated under a state permit. Conditions for these permits include systems in environmentally sensitive areas, unsubstantiated or unexpected flow volumes, and systems requiring exceptional operation, monitoring, and management.

D.

If flow values, as determined according to part 7081.0110, are greater than 10,000 gallons per day but an SDS permit is not required because of subpart 1a, item B, flow measurement data generated for making that determination must be submitted to the commissioner for review before a local permit is issued. Information on all subsequent alterations to the flow must also be provided to the commissioner.

Subp. 1a.

Flow determination.

The owner or owner's agent must determine flow according to this subpart to establish whether an SDS permit is required under subpart 1, item B.

A.

For new SSTS and expansions to existing SSTS, the flow must be determined according to item C.

B.

For existing SSTS, except as provided under item D, the flow is determined:

(1)

by calculating the average of the maximum measured daily flow for a consecutive seven-day period when the following measurements are recorded and used in the calculation:

(a)

90 consecutive daily flow measurements capturing the maximum use. Measurements must be corrected for occupancy or use according to Prescriptive Designs and Design Guidance for Advanced Designers, incorporated by reference under part 7080.1550, subpart 2; and

(b)

40 additional, consecutive, weekly flow measurements validating that unit (a) captured the maximum use; or

(2)

according to item C.

C.

When determined according to this item, flow is calculated according to part 7081.0110. The highest calculated value of the various methods in Table I under part 7081.0130, subpart 1, must be used to make the determination, with no reduction allowed. An SDS permit is not required if a factor of safety is added to the design flow that results in a design flow that exceeds the SDS permit threshold.

D.

Campgrounds and resorts existing as of June 14, 2015, that are open 180 days per year or less must determine flow in accordance with this item or item A or B.

(1)

Flow measurements must be taken only from:

(a)

a sewage lift station pump with a runtime meter and counter;

(b)

a sewage flow meter;

(c)

flow meters on wells; or

(d)

a water softener system with flow measurement when the measurement includes all flow to the subsurface soil treatment system, including backwash.

(2)

Flow measurement devices must be calibrated before start-up of monitoring and must undergo an additional calibration during the measurement period to verify results.

(3)

The daily flow rate and daily occupancy rate must be recorded for a minimum of two weeks centered on and including July 4. Weekly measurements must also be done for an additional, continuous two weeks before and two weeks after July 4.

(4)

Flow measurements must be divided by the percent occupancy expressed as a decimal percent.

(5)

Flow extrapolation from systems not measured is allowed as follows:

(a)

flow may be extrapolated only if fewer than 25 percent of the systems are not measured;

(b)

the systems measured must serve at least 75 percent of the occupancy of the campground or resort; and

(c)

flow extrapolation is not allowed between other campgrounds and resorts.

(6)

If no flow data exist, the owner or operator of the campground or resort must implement an acceptable flow measurement plan and start measuring and recording flow data within 120 days of notification. An acceptable flow measurement plan is a plan, verified by the agency, conforming to subitems (1) to (5).

(7)

All flow measurement data generated from the flow measurement plan must be submitted to the commissioner within 30 days of the last measurement.

Subp. 2.

Other state regulations.

A.

MSTS must conform to all applicable state statutes and rules.

B.

MSTS serving establishments licensed or regulated by the state of Minnesota, or MSTS owned by the state of Minnesota, must conform to this chapter.

Statutory Authority:

MS s 115.03; 115.55; L 2015 1Sp4 art 4 s 144

History:

32 SR 1400; 35 SR 1353; 41 SR 312; 45 SR 725

Published Electronically:

January 22, 2021