• Septic Information:


  • Septic System FAQs

    How do I increase the operating life of my septic system?
    All private sewage systems are designed based on a gallon per day discharge rate from the building being served (i.e. number of bedrooms or building usage, if a public building). Since private sewage systems have a finite life, proper maintenance is important as a means of providing system longevity. Owners of private sewage systems should be aware of the following maintenance recommendations as a means of increasing private sewage system life.

    1. Make it a practice to conserve water within the home.
    2. Wash clothes over a period of several days trying not to wash more than one load per day.
    3. Install reduced flow plumbing fixtures or water saving devices like reduced flow shower heads, a suds-saver feature on the washing machine, or flow restrictors.
    4. Repair dripping faucets, float valves etc.
    5. Only biodegradable materials should be discharged to the septic system. Materials such as cigarette butts, sanitary napkins, paper towels, facial tissues, disposable diapers, coffee grounds etc. should be disposed of in the trash.
    6. Fats and greases should not be discharged to the septic system.
    7. If a garbage grinder is installed, its use should be minimized in order to avoid discharging an excessive amount of finely ground solids to the septic system.
    8. Periodically have a licensed septic tank pumper inspect and pump the septic tank to insure that it is operating properly and to remove any indigestible accumulated solids from the tank. Septic tank maintenance on a two-year basis is recommended.
    9. The addition of chemicals, enzymes, yeasts or other additives to the septic tank will not eliminate the need for periodic maintenance nor will they cure a failing septic system. Some chemicals may even be harmful to a septic system. In Wisconsin, the State Department of Commerce must approve chemical additives. Either check with the County or with the regional Department of Commerce office Link to obtain information on approved chemical additives
    10. Do not drive cars or heavy equipment over the septic system.
    11. Educate yourself about your septic system and how it operates. Do not build over the septic system. Know where the septic tank, pump tank or absorption field is located and be aware of its limitations. 
    Will the use of additives increase the operating life of my septic system?
    For some people served by private sewage systems the thought of an expensive system failure is never far from their minds. Advertisements for septic tank additives that can completely eliminate this worry looks tempting but these claims could be exaggerated.

    Some advertisements for septic tank additives claim to completely prevent clogged drains, entirely eliminate the need for routine pumping, and rescue failing systems.

    Introducing live bacteria or enzymes into a failing system may not offer much help because septic systems usually fail as a result of old age or neglect of clogged absorption fields, not from the lack of bacteriological action. Because septic systems are designed to catch solids, all tanks will eventually fill with indigestible solids (sludge). No chemical, enzyme or bacteria can digest sand, soil other inert materials. Indigestible solids that accumulate in the tank can wash into the soil absorption field if they are not pumped out. These solids can clog soil pores and prevent water from percolating through the soil absorption field. When the tank is more than half full of sludge there’s too little room for incoming wastewater to remain in the tank long enough to be treated properly. Grease and scum that accumulate on top of the wastewater must also be removed when the tank is pumped to prevent them from washing into the soil absorption field.

    The Environmental Health Division recommends that a licensed pumper routinely pump your septic tank every 2-3 years even if additives are used. The cost of pumping a septic tank is often much less than you would pay for a year’s supply of septic tank additives.

    While there is no accepted test method to prove septic tank additive products are effective, some products are actually harmful. In Wisconsin, all products claiming to aid digestion in septic systems must be reviewed prior to sale by the Department of Commerce for proof they do not adversely affect:

    • The bacterial action in the private sewage system;
    • The soil hydraulic conductivity in the soil absorption field; or
    • The groundwater quality beneath the private sewage system.

    There are no known chemicals, yeast, or other substances capable of eliminating or reducing solids in a septic tank so cleaning is unnecessary. The use of septic tank cleaners does not replace the need for regular pumping of the septic tank and general maintenance of the private sewage system.

    How long can I rely on a soil test?
    The county reserves the right to question any soil test report submitted and require an on-site evaluation to verify the information submitted by the certified soil tester. Soil test reports submitted to the Waukesha County Environmental Health Division are reviewed shortly after being received for accuracy and completeness. Most questions are resolved shortly after submission and the soil test report is filed to await the submission of private sewage system plans.

    Pre-1980 Soil Test Reports
    Due to changes in soil test submission requirements, if your soil test report is pre-1980, you will need to provide additional information before a sanitary permit can be issued.

    Soil Test Reports Dated between 1980 and 1991
    If your soil test was conducted between 1980 and 1991 using the percolation test method, it can be used for septic system design and sizing if Environmental Health Division staff agrees with the information provided and it is complete.

    Post 1991 Soil Test Reports
    July 1991 changes in the Wisconsin Administrative Code prohibited the use of percolation tests to determine absorption area, and a new procedure for evaluating and reporting soil and site evaluation was put in place. Soil tests conducted from July 1991 to the present are acceptable and are expected to continue being accepted for years to come provided the site has not been altered by cutting and/or filling and there is no reason to question the soil conditions as they were reported.


    Pre-1980 Soil Test Reports
    Due to changes in soil test submission requirements, if your soil test report is pre-1980, you will need to provide additional information before a sanitary permit can be issued.

    Soil Test Reports Dated between 1980 and 1991
    If your soil test was conducted between 1980 and 1991 using the percolation test method, it can be used for septic system design and sizing if Environmental Health Division staff agrees with the information provided and it is complete.

    Post 1991 Soil Test Reports
    July 1991 changes in the Wisconsin Administrative Code prohibited the use of percolation tests to determine absorption area, and a new procedure for evaluating and reporting soil and site evaluation was put in place. Soil tests conducted from July 1991 to the present are acceptable and are expected to continue being accepted for years to come provided the site has not been altered by cutting and/or filling and there is no reason to question the soil conditions as they were reported.

    I want to improve my home. How close can I build to my private sewage system?
    The Wisconsin Administrative code establishes minimum isolation distances between the septic tank/soil absorption field and various improvements made on the property. A partial listing of some of the minimum isolation distances are as follows:
    Proposed Improvement Minimum Distance to the Septic Tank  Minimum Distance to the Soil Absorption Field 
    Concrete Slab
    (Floating or with frost footing that is not connected to the building)
    5 feet

    10 feet

    Concrete Slab
    (With frost footing that is attached to the dwelling) 
    5 feet

    15 feet

    Wooden Deck
    (Constructed with or without concrete or wood pilings) 
    5 feet

    10 feet
    Attached garage on slab 
    5 feet 15 feet
    Detached garage on slab 
    5 feet 10 feet
    Swimming Pool above or below ground 
    5 feet 15 feet
    Habitable slab constructed building 
    5 feet 15 feet
    Screen in porch with roof 
    5 feet 10 feet
    Porch with combination windows and roof 
    5 feet 15 feet
    Building addition with crawl space and/or basement 
    5 feet  25 feet
    Building addition on slab 
    5 feet 15 feet
    Private Well 
    25 feet 50 feet
    Lot Line 2 feet 5 feet 
    Lake or stream high water mark  25 feet  50 feet