Why We Engineer Septic Systems in Mid-Michigan: Benefits, Types, and Local Regulations
- Casey Fiedler
- 45 minutes ago
- 5 min read
In Mid-Michigan’s Ingham, Jackson, Eaton, Clinton, and Livingston counties, challenging site conditions—such as clay-heavy soils, high seasonal water tables, and smaller lots—often make traditional septic systems impractical or impossible. That’s why we engineer septic systems: to deliver reliable, compliant wastewater treatment tailored to your property’s unique limitations.
Septic systems generally fall into two broad categories: conventional and alternative (commonly referred to as “engineered” systems in our area). While the term “engineered” is widely used, it does not necessarily mean the design must come from a licensed professional engineer. Depending on local health department rules, qualified designers can include Registered Environmental Health Specialists (REHS), experienced contractors, or individuals certified by proprietary system manufacturers.
As a trusted local provider serving Ingham, Jackson, Eaton, Clinton, and Livingston counties, we guide homeowners through these options every day and maintain certified design professionals on our staff, helping you understand what’s required and why.
Conventional vs. Alternative (Engineered) Septic Systems: What’s the Difference?
Conventional systems rely on a septic tank for primary treatment followed by a gravity-fed drain field where soil naturally filters the effluent. These work well on sites with deep, well-draining soils and adequate separation from groundwater.
Alternative or “engineered” systems are required when site restrictions prevent a conventional system from functioning properly or meeting code. Bear in mind that Michigan is one of the last states without a uniform state level septic code. This means requirements from one county to the next can vary WIDELY. It's important to get information from your specific county health department as it may not align with what you're reading or learning elsewhere.
In our Mid-Michigan counties, the most common triggers are:
Poorly draining clay soils
High seasonal water tables
Limited lot size or setback constraints
Once your local health department conducts a soil evaluation (often called a “perc test”), they will determine whether a conventional or alternative/engineered system is needed. For more on Michigan’s onsite wastewater guidelines, visit the Michigan EGLE Onsite Wastewater Management page.
Who Can Design an Engineered Septic System?
Design authority varies by county:
Some health departments (or their staff) can design certain alternative systems themselves.
Others require an independent designer, which may be a private engineer, REHS, or manufacturer-certified professional.
Always verify with your county health department what qualifications they accept. Most health departments maintain a list of approved designers and submitting a design from a contractor that's not on their approved list may result in a flat out denial. Be sure to hire a certified and qualified professional. This flexibility allows more options but also means the designer you work with might only be approved for specific system types. Contact your local health department for details:
Types of Alternative (Engineered) Systems: Passive, Active, and In-Between
Alternative systems can be further divided into passive, active, and hybrid approaches:
Passive Systems
These rely primarily on gravity and natural processes with minimal mechanical components.
Examples: Infiltrator ATL, chamber systems, or gravel-less distribution products.
Advantages: Lower operating costs, no electricity required for treatment, simpler maintenance.
Best for: Sites needing enhanced dispersal but not intensive pretreatment.
Hybrid/Middle-Ground Systems
These provide additional treatment without constant mechanical operation.
Examples: Sand filters, media filters, or textile filters.
Advantages: Excellent effluent quality with moderate maintenance; often non-proprietary (generic designs approved in many jurisdictions).
Best for: Sites needing better polishing than passive but less complexity than fully active systems.
Note that specifically in Michigan media filters have seen mixed use and mixed approvals with some counties reversing approval for installation of new media filters. Check with your local county.
Active Systems
These use mechanical components for enhanced treatment.
Examples: Aerobic Treatment Units (ATUs) with continuous air pumps.
Advantages: Highest level of treatment; can support very small footprints or sensitive environments.
Drawbacks: Higher energy use, more frequent maintenance, and often proprietary (may require service contracts with certified providers).
All alternative systems—whether passive, hybrid, or active—typically require extra care compared to conventional setups. Many have manufacturer-specific maintenance requirements and may be subject to additional local or state health department oversight.
Be sure to look into the costs of ongoing maintenance and inspection needs for these system types as they can be very costly over the life of the system. If possible, a passive system may reduce costs in some cases.
Key Questions to Ask Your Designer
Not all designers are qualified (or approved) to work with every type of alternative system. To ensure you get the best solution for your property and budget:
Ask what type of system they plan to propose and why it’s suitable.
Inquire whether other options exist that might be more cost-effective or lower-maintenance.
Confirm that the recommended system meets your county’s specific requirements.
Some designers, including certain health departments, are limited to only one or two system types. Usually designers will conveniently fail to mention that other options may be available. You will need to be your own advocate or you may just get whatever type of system is easiest for the designer to put together. We often see engineered or alternative system designs that bring into question whether the designer truly had their clients best interest in mind - or just wanted to get paid with as little hassle as possible.
Exploring multiple qualified professionals can reveal better or more affordable alternatives you might otherwise miss.
Navigating Local Regulations and Permitting in Ingham, Jackson, Eaton, Clinton, and Livingston Counties
Michigan has no uniform statewide septic code—each county’s health department enforces its own sanitary code. Common steps include:
Soil evaluation/perc test
Design submission (by approved designer)
Permit review and issuance
Construction inspections
Final approval
Time-of-transfer evaluations are required in many transactions, making a properly permitted system essential for selling your home. Check your county’s specific resources linked above for applications, fees, and requirements.
FAQs: Alternative and Engineered Septic Systems in Mid-Michigan
When is an engineered/alternative septic system required? When soil tests reveal poor percolation, high groundwater, limited space, or other restrictions that prevent a conventional system from meeting code.
Do I need a licensed engineer to design my system? Not always. Many counties accept designs from REHS staff, certified contractors, or manufacturer-trained professionals—check with your local health department.
Which system is cheapest to operate? Passive systems generally have the lowest ongoing costs (no electricity, minimal maintenance). Active systems like ATUs have higher operating expenses.
Can my health department design the system for me? Some counties will; others require a private designer. Ask early in the process.
How do I know I’m getting the best option? Get quotes from multiple approved designers and compare system types, upfront costs, long-term maintenance, and energy use.
Ready for the Right Solution on Your Property?
Understanding the differences between conventional and alternative systems—and knowing your options within the engineered category—empowers you to make informed decisions. Whether you need a simple passive design or a high-treatment active system, the goal is the same: reliable performance that protects your home and Michigan’s public water resources.
If you’re in Ingham, Jackson, Eaton, Clinton, or Livingston counties and facing septic challenges, contact us today for a free consultation. We’ll explain what your soil evaluation means, explore all suitable options, and design a system that fits your needs and budget.