Septic System Installation & Replacement FAQ's

We can even install around a corner, on a slope.

What are the parts of any septic system?

Any properly designed septic system consists of the following components:

1. Source (the house or building attached to the system)

2. Collection & Storage (the pipes that take wastewater to the tanks)

3. Pretreatment (septic tanks)

   • (Optional) Advanced Pretreatment (aerobic treatment units, etc.)

4. Final Treatment & Dispersal (in-grade trenches, mound, lagoon, etc.)

Is a "mound" required if I install or replace my septic system?

The short answer: No.

The long answer:

The mound systems commonly seen around Mid-Michigan are one of several types of "advanced" or "alternative" final treatment more broadly classified as bottomless sand filters. You may recognize them as a tall berm in your neighbor's yard or around the area you live.

These types of final treatment are in common use around Mid-Michigan for several reasons, but here are a few common reasons:

• A mound system allows the pipes which carry the wastewater to the soil to be elevated above the native grade. This is important in cases where a limiting layer such as standing water table, seasonal high water table, or other limiting factors such as restrictive soils layers would otherwise not allow a "conventional" drainfield to exist.

• Mound systems utilize pressure distribution of the wastewater. Pressure distribution involves the use of a pump to evenly dose the wastewater across the entire surface of the final treatment area. This is in contrast to gravity distribution which results in non-uniform wastewater delivery to any drainfield. Uniform distribution of wastewater has many advantages.

Some myths have circulated in recent years that mound systems are being mandated for any new builds or replacement systems. This is not the case. Mound systems are not required in every case (at least around Mid-Michigan).

For instance, in Ingham County where we are based, we experience about a 50/50 even split in permits which call for a conventional system versus permits which call for an alternative system (such as a mound).

I don't want a mound, what can I do about it?

As discussed in the other FAQ section, mound systems are not required in all cases. If you want to improve your chances of avoiding a mound systems here are some tips:

For new builds have your local county health department, or other regulator writing your septic permit, perform a soils evaluation on the site prior to purchasing it. This will tell you ahead of time what type of septic system will be required at that site. Often, you can make your purchase of a parcel contingent on the results of the site soils evaluation so if the results come back unfavorable you can move on if you'd prefer or perhaps negotiate on the price.

When it comes to replacement septic systems options become more restrictive. Because replacement systems occur when a home and parcel is already laid out, it's may be much harder to find options. You may be left with just the layout and acreage to work with that's available.

That said, if your permit comes back requiring an alternative system, do keep in mind that there are many types of alternative septic systems. Your standard "pipe in stone" mound system is just one of many alternative system options available, though your local health department or contractor may not even be aware other options exist.

Contact Michigan Septic and we'll be happy to look at your situation and advise you on the full range of options you actually have available to choose from!

Can I reduce the size or height of my mound system?

Yes!

Many contractors and homeowners are not even aware of this. It is possible to reduce the size and heigh of your mound septic system and Michigan Septic can help you with that!

Not only does a shorter, smaller mound look better in your yard - it also costs less to install. Due to the reduction in materials, machine hours, and labor used to build a smaller system you get a more visually appealing system at a lower cost!

Michigan Septic is trained and certified to design, install, and service septic systems which take advantage of advanced final treatment in order to create a cleaner wastewater. This means in many cases we can get approval to reduce the size and height of your final treatment area!

I'm thinking about building, what will my septic system cost?

Note: Prices, permit requirements, and other factors change quite dramatically from one county to the next in Michigan. No one can tell you with 100% certainty what your system will cost until you have an approved permit to get an accurate estimate.

Septic system costs in Mid-Michigan fall into one of two main baskets: conventional septic systems, and alternative septic systems (sometimes call "advanced").

How do you know which one you will have to install? You'll need a site soils evaluation (sometimes still called a "perc test" though the process is quite different). Once your local county health department or other permitting entity has performed a soils evaluation on your site, they will tell you which category of system you need to install.

In many jurisdictions, if the system required is conventional, the permit will also contain the septic system design and can be sent to your preferred contractor for an estimate of installation cost.

However, if the permit requires an alternative septic system most of the time you'll need a qualified septic system designer to create the plan for your system which will then be reviewed and approved by the county or other permitting body. Ask the person who wrote your permit for a list of approved septic system designers in your area.

SAVE MONEY: Not all septic system designers are created equal. An unfortunate number of system designers simply use a "cut and paste" approach to apply the same system to every site they create a design for. We know this is true because at Michigan Septic we often have to "re-design" septic systems brought to us by our clients because the initial design is large, costly, and otherwise inefficient from a financial perspective.

Michigan Septic may be able to improve your septic system design and save you thousands! In fact, we have saved our clients more then $10,000 on several occasions by re-designing a system for them prior to installation.

For common residential septic systems the following price ranges may be seen around Mid-Michigan in 2024 (Note that there are always exceptions.):

System Type	Low End	Average	High End
Conventional	$8,000	$10,500	$14,000+
Alternative	$18,000	$24,000	$40,000+

Can I reuse my existing septic tank when replacing my system?

Reusing a septic tank when replacing your septic system is a roll of the dice in most cases. There are two factors to keep in mind:

• Some counties or permitting authorities may have a blanket policy that does not allow the re-use of an existing septic tank when replacing your system. Often if the tank is more than a certain number of years old, they will mandate replacement.

• Commonly, the permitting authority may allow reuse of the existing septic tank if it is pumped, inspected, and found to be sound by a qualified service professional.

What is a perc test?

Perc tests, while now mostly antiquated, were the prevailing methodology for evaluating the soils at a given site for a septic system historically. A hole would be dug and a known quantity of water added to the hole. The amount of time required for the water to "percolate" or "perc" into the soil would then be used as the basis for determining what type and size of septic system should be installed.

Today, however, we know that the perc test is not so accurate as it once was believed to be. Instead, a site soils evaluation is typically used. Site soils evaluations, when performed properly, can tell the evaluator a lot more about the soil layers, soil types, soil structure, and other factors which combine to affect the size, type, and performance of your septic system.

Rarely, a perc test may still be performed in some areas or very specific situations. Typically, this should be done in combination with a properly performed soils evaluation as well.

Some people will still refer to any soils evaluation as a "perc" due to the prevalence of the word over time. It doesn't hurt to ask for clarification if you're confused when talking to your permitting authority or contractor.