Although septic tank additives containing bacteria or chemicals are commonly marketed to improve septic system maintenance and performance, the use of these additives is not recommended, as these additives may have a potentially harmful impact, and are not necessary for the functioning of a septic system. The bacteria, enzymes, yeast, fungi, and other microorganisms required for septic tank functioning already exist as a result of normal use. See this U.S. Environmental Protection Agency (U.S. EPA) fact sheet on septic tank additives.

An in-sink garbage disposal can have a negative impact on a septic system and increase how often your tank may need to be pumped. Food waste contains a lot of fats, oils, and grease that does not break down in a septic tank. Garbage disposals can add more than normal amounts of sludge and scum to septic tanks since the additional food and grease is slow to be digested by the bacteria within the septic tank. With large gushes of water, the food solids in the scum and sludge can be pushed out into the soil absorption system and clog the pipes and the small soil pores. Additionally, garbage disposals can result in smaller solids that cannot easily settle out of the septic tank liquid, which may also end up in the soil absorption system. Avoid putting food into the garbage disposal. If you must use a garbage disposal, your septic tank will most likely need to be pumped more frequently.

Residential septic systems in Michigan are not designed to receive backwash discharges from water softeners or other water treatment devices. In most cases, the various local sanitary codes prohibit connection of these devices to the septic system. Water softener backwash has a high salt content that may impact the buoyancy and settling in the tank. Also, some studies have questioned if the brine may result in premature degradation of the septic tanks. 

Other water treatment devices, such as reverse osmosis systems, have the potential to dispose of four gallons of water for every one gallon of filtered water produced. The additional water produced may result in too much water, called hydraulic overload, into the soil absorption system. Most systems are not designed to accommodate the additional water from a water treatment discharge.

It is recommended that these discharges are connected away from your septic system. This could be accomplished by connecting to the sump pump or a separate system such as a french drain, a separate infiltration system, or stone bed. If you have a home drinking water well, locate these discharges at least 50’ from your home’s water supply. It is advisable to contact the local health department and the local plumbing authority to ensure that any local requirements are met.

Household cleaners can be okay to use in small quantities, but it is suggested to avoid overuse. It is also recommended to look for a “septic safe” label on all cleaners and detergents used in the home. 

It is important to avoid the use of excessive bleaches, detergents, strong disinfectants, and “every-flush” toilet disinfection chemicals. Quaternary ammonia cleaners can be problematic for septic tank bacteria, and therefore should be used sparingly or not at all. The below items should not be washed down any drains and can be particularly harmful in a septic system and can result in system failure. Do not flush the following down your drains:

• caustic drain cleaners and other potentially harmful chemicals
• prescription drugs
• motor oil or brake fluids
• paints and paint thinners
• solvents
• herbicides and pesticides
• anti-freeze
• gasoline
• chemical wastes
• sanitary wipes
• cat litter
• feminine hygiene products
• excessive cooking grease or waste oil
• food waste or coffee grounds

A conventional septic system’s lifespan is about 25-40 years. Septic system lifespans can vary depending on the design, material of components, and use and maintenance of the system. Electronic components of a septic system such as pumps, alarms, and/or control panels have a shorter expectant lifespan than a septic tank and drainfield.  

It is important to keep up on maintenance to prolong the life of your septic system. Ensure to follow any manufacturer or installer maintenance requirements, have the septic tank serviced regularly (including cleaning the effluent filter if one is installed), and inspect the septic system yearly for signs of failure. 

Yearly inspection should include: 

• Open and inspect all tanks. 
• Have the tanks pumped if needed (recommended if over 1/3 full of scum and sludge). 
• Inspect and clean the effluent filter (if one is installed). 
• Test components of the control panel (if one is installed) including the alarm and pump. 
• Walk around the drainfield to look for signs of failure. 
• Check inspection ports (if installed) for any standing water. 
• Check for leaking faucets or toilets inside the building.  

The drainfield is vital to a functioning septic system. Having unsuitable landscaping on and around your system can result in root infiltration that can clog the sewer lines and the soil pores. Root infiltration is one of the leading causes of system failure in Michigan. It is recommended to isolate trees and large shrubs from the edge of your system or even further for large trees with expansive or water seeking root systems such as walnut, maple, cottonwood, aspen, or willow trees. Generally, keep trees away from the septic system and far enough so the dripline of mature trees will fall outside of the drainfield area. 

Once roots are within the system, it is often difficult to remediate the issue. Additives to kill the roots may be considered; however, additives will not remove the roots that already exist in the system or prevent future root growth. Often, significant root intrusion into the system can result in the need for major repairs or replacement of the system. It is best practice to prevent the growth of roots into the systems before the problems occur.  

Here are two resources that discuss appropriate landscaping for around the septic system: 

1. Native Plants Suitable to Grow Near a Drainfield? - Septic System Education (MSU.edu) 
2. Proper Landscaping On and Around Your Septic System - U.S. EPA Septic Smart

Isolation distance requirements between septic systems and wells vary depending on the type of system and the applicable regulations. In the State of Michigan, the Well Construction Code set a minimum isolation requirement of 50’ between a single family private well and a septic system. However, some local sanitary codes have greater isolation requirements. Additionally, wells that serve other than single-family homes, have larger isolation distance requirements as established in the Safe Drinking Water Act and Rules.  

Isolation distances from a septic system to lakes, rivers, and other surface water bodies also vary depending on the type of system and the applicable regulations. The isolation distance requirements from a septic system to a surface water are no less than 50’ in any jurisdiction but can be up to 100’ for septic systems in a subdivision or condominium development. Some counties in the state have local sanitary codes that require an isolation distance to surface water of 75 to 100 feet.

Where the existing system does not meet the isolation requirements, there may need to be an evaluation of the system to establish if a health concern is present. Maintaining required isolation distances provide for a good minimum level of protection, however, where a system has failed or where a straight pipe is present, there still may be concerns present. Reach out to your local health department if you have questions about the isolation distance requirements for your system.

Typically, a properly installed, sited, and maintained septic system should not adversely affect water quality. Septic systems rely on an adequate depth of dry permeable native soil underneath the drainfield to treat the wastewater before it reenters the ground water. In some situations, additional design requirements, such as advanced treatment, may be necessary to overcome site conditions and/or provide additional protection to groundwater and/or surface waters.

If a system is failing or sewage discharges directly into the groundwater and/or surface waters, the wastewater is not treated to reduce pathogens or nutrients levels. In these cases, there may be a negative impact on water quality and public health. 

For more information, see the U.S. EPA's web page, Septic System Impacts on Water Sources.

OWMU and local health departments refer to the following definition of a septic system failure*: 
A system is considered to have failed when sewage backs up into the home or structure, discharges to the ground surface, contaminates surface water, or drinking water supplies, any part of the system is bypassed, the system is the source of an illicit discharge, there is an absence of an absorption system, or there is a structural failure of a septic tank or other associated appurtenances.
Some signs of failure in a system include: 

• Water and sewage from toilets, drains, and sinks backing up into the building’s plumbing
• Slowly draining bathtubs, showers, and sinks
• Gurgling sounds in the plumbing system
• Standing water or damp spots near or over the septic tank or drainfield
• Bright green, spongy or lush grass over the septic tank or drainfield
• Sewage odors around the septic tank, drainfield, or straight pipe discharges
• Visible pipes discharging partially treated or untreated sewage to the ground surface
• Algal blooms in nearby lakes/waterbodies or high levels of nitrates or coliform bacteria in surface waters or drinking water wells not associated with other sources of contamination

If you suspect that you are experiencing a septic system failure, contact your local health department for guidance on how to proceed.  You can also refer to the U.S. EPA webpage, Resolving Septic System Malfunctions.

*To view reports summarizing Michigan’s Failed Sewage System Evaluations, go to EGLE's Onsite Wastewater page at Michigan.gov/EGLEOnsiteWastewater.

More information on septic systems can be found online at: 

• EGLE Onsite Wastewater SepticSmart page
• EPA’s Septic Systems (Decentralized/Onsite Systems) page
• National Onsite Wastewater Recycling Associations (NOWRA) Homeowner Training
• Michigan State University Extension Septic System Education
• To locate a company to pump your septic tank: Septage Hauler Directory