Aerobic and alternative septic systems in Michigan: oversight, permits and what to ask

The family of alternative systems

Aerobic treatment units are one member of a group EPA calls alternative systems. An aerobic unit injects oxygen into the treatment tank, and EPA says it can serve smaller lots, poor soils, high water tables or sites near sensitive water. It adds that regular lifetime maintenance should be expected. Mound systems are another kind: EPA says a mound suits shallow soil, high groundwater or shallow bedrock, and that drip distribution gets by without a large mound. Both depend on upkeep after installation.

What makes a system alternative, in practice, is that something more than a tank and a gravity drain field is doing the treatment. That something has parts that fail: EGLE says electronic components such as pumps, alarms and panels have a shorter expected life than the tank and drain field, and EPA says pumps and controls often need replacement every 10 to 20 years. That helps explain the oversight, and it is why a buyer should read the maintenance file before the inspection report.

How Michigan oversees them

Section 12757 of the Public Health Code governs acceptable innovative or alternative waste treatment systems. The local health department regulates them and may inspect each one at least once a year. The same section says the owner is not exempt from sewer special assessments, and in some cases need not connect to a public sewer. The statute’s definition of the systems that section 12751 covers excludes a plain septic tank and drain field, so the yearly inspection power is aimed at systems like these.

EPA’s guidance points the same way. Alternative systems with electrical float switches, pumps or mechanical components should generally be inspected once a year, and EPA adds that a service contract matters. No Michigan statute we can cite requires a service contract, and no state rule says who may service an aerobic unit. A county can add either requirement.

County operating permits and certified installers

Counties turn the yearly inspection into paperwork. Oakland County’s sanitary code requires an annual operation permit for alternative and engineered systems with pretreatment. The permit is not transferable when the property changes hands, maintenance follows the manufacturer’s schedule or the Health Officer’s frequency, and a maintenance report is due within 30 days of each service. Oakland’s fee schedule lists a $360 review for an alternative-system technology and $50 for the annual residential review.

Livingston County issues annual operating permits for alternative systems and says they are non-transferable too, with a $43 annual fee and a $780 permit for the technology itself. Barry-Eaton District Health Department says certain technologies, including low-pressure dose mounds over slowly permeable soils, lagoons and alternative pretreatment systems, may be installed only by installers it has certified, while conventional systems do not need one. Its FY2027 schedule lists $1,333 for an alternative system in new construction. Ottawa County lists $1,020 for a raised or pressurized mound or alternative design, and its code lets the health officer require training or certification of contractors for alternative systems only; confirm that wording with the county. Genesee County allows a field reduction of 30 percent for technology certified to NSF Standard 40, a figure that comes from a PDF layout, so check it with the county before you rely on it.

EGLE’s loan program and the product registry

EGLE’s septic replacement loan program sorts installations into two categories. Category 1 uses a conventional design with at least 18 inches of non-mottled soil. Category 2 relies on performance-based treatment, and those systems must be certified to NSF Standard 40, operated and maintained for life, and covered by reports at least every three years that are recorded against the property. Every system the program pays for must also follow EGLE’s minimum standards, which call for a watertight riser to grade and a tank sized by local code. EGLE keeps a list of approved manufacturers for loan work, with contingencies, and we do not reproduce it here because a product list on a referral site reads as an endorsement.

Senate Bill 771 of 2026 would require proprietary treatment products to be registered with EGLE, with a $3,000 application, before they could be installed. As of Oct 19, 2026 the bill was waiting on third reading in the Senate, so no registry exists yet.

What a yearly service should cover

EGLE’s yearly list for owners is a fair minimum for an alternative system: open and inspect all tanks, pump if the tank is more than one-third full of scum and sludge, clean the effluent filter, test the control panel alarm and pump, walk the drain field, and check the inspection ports for standing water. The loan program’s standards add an effluent filter on pressure or proprietary systems, so ask whether yours has one and who cleans it. Oakland County requires the servicer’s operation and maintenance report within 30 days of each service.

Buying a house with an alternative system

Ask four things. Is there a current county operating permit, and what must a new owner do, given that Oakland’s and Livingston’s do not transfer? Where are the maintenance reports for the last several years? Who services the unit, and is there a contract? When were the pump, floats and panel last replaced? EGLE’s yearly list includes testing the alarm and pump, so a seller with no record of that has told you something. Then read the pump and float page for the parts and the county rules tool for what we have on file about your county.

Prices and counts the sources do not give

No Michigan or government source we can cite prices an aerobic unit. EPA says only that alternative systems cost more than the $5,000 to $15,000 it gives for repairing a conventional one, and EGLE says a Michigan replacement system costs $8,000 to $30,000. Nor did we find a count of Michigan homes with aerobic units, or a source ranking any brand above a conventional design. That choice follows the soil and the county.