Resolving Septic System Malfunctions

Why septic systems malfunction

Septic system replacement

Most septic systems malfunction because of inappropriate design or poor maintenance. Some soil-based systems (those with a drain field) are installed at sites with inadequate or inappropriate soils, excessive slopes, or high ground water tables. These conditions can cause hydraulic failures and contamination of nearby water sources.

Failure to perform routine maintenance can cause solids in the tank to migrate into the drain field and clog the system. Regular maintenance, such as pumping out the septic tank, should be done at least every three to five years. Also, being conservative with water and product use will reduce the load to the system and add to longevity.

What to do if your home floods

If sewage from your plumbing fixtures or onsite system backs up into your home, avoid contact with the sewage as it may contain harmful pathogens. Contact your local health department or regulatory agency for guidance. Cleanup personnel should wear protective clothing (e.g., long rubber gloves, face splash shields).

After cleanup is complete, thoroughly wash all equipment, tools, and clothing used during cleaning as well as the flooded area. Disinfect all items or areas exposed with a mixture of 90 percent water and 10 percent household bleach. The area should be dried out thoroughly and not used until it has been completely dry for at least 24 hours.

For more information:

Whom to contact for help with your septic system

Contact a local septic system service provider, your local health department, or onsite wastewater treatment regulatory agency. Find the telephone number for your local health department online or in your local phone directory.

There are online searchable databases of installers and septic system service providers to find a professional in your area:

Frequent Questions on Resolving Septic System Malfunctions

  • How can I prevent a septic system failure?
    • Regular maintenance is the best method to prevent a septic system failure. Septic maintenance includes inspecting the entire system every 1 to 3 years and pumping the tank every 3 to 5 years. The frequency for pumping the septic tank depends on the tank size, number of people in the household, the water habits and use, if a garbage disposal is used, and the amount of solids accumulated in the tank. A rule of thumb is to pump the tank when the solids are two-thirds of the volume in the tank. Routine maintenance is the responsibility of the home or property owner. If you rent a home, you have responsibility for the proper use and operation of the system.
    • In general, you can avoid a septic system failure by:
      • Inspecting your system every 1 to 3 years
      • Pumping the tank every 3 to 5 years or as needed
      • Avoiding excess water use (e.g. spreading out laundry use over the week)
      • Flushing only human waste and toilet paper down the toilet.
  • What are common signs of a failing septic system?
    • Water and sewage from toilets, drains, and sinks backing up into the home’s plumbing
    • Bathtubs, showers, and sinks draining very slowly
    • Gurgling sounds in the plumbing system
    • Standing water or damp spots near or over the septic tank or drainfield
    • Sewage odors around the septic tank or drainfield
    • Bright green, spongy lush grass over the septic tank or drainfield, even during dry weather
    • Straight pipe discharging untreated wastewater to the ground surface
    • Algae blooms in nearby lakes or waterbodies
    • High levels of nitrates or coliform bacteria in surface waters or drinking water wells
  • If I smell a foul odor coming from my septic system, does that mean my system is failing?
    • There may be several reasons for the smell, which can occur inside or outside your home. If you notice an odor, it may be coming from a roof vent or other vent pipe that allows the system pressure to equalize. This is a normal part of your system. Sometimes these vents can become obstructed and clogged (from leaves, debris, etc.) or the vent pipe can freeze during prolonged cold spells. These situations could cause an odor inside or outside of your home. Another possibility is a down draft (changes to wind pattern) or other location-specific conditions, which can create an odor inside or outside your home. In these cases, the vent may need to be cleaned or raised. There are charcoal filters available for roof vents that may also alleviate the odors.
    • If your drainfield is not working properly, that could be another reason you smell an odor inside your home or around the septic system. Soft, wet, or spongy soil (especially when there have been no significant rainfall events) around your drainfield is a good indication of a system failure. For general information on maintenance of your septic system, consult EPA’s A Homeowners’ Guide to Septic Systems.
    • It is not possible to diagnose the exact cause of an odor remotely. EPA recommends you contact a local septic system service provider and/or plumber to address the issue. 
  • What about a smell from the septic system in my recreational vehicle (RV), boat or mobile home?
  • What should I expect in a typical septic system inspection?
    • Septic system inspections are a vital step in making sure your system is operating properly. Regular inspections ensure you and your family do not get sick due to a leak or other problems with your septic system. Since these wastewater systems are located underground, homeowners may overlook having a septic inspection. Routine inspections help prevent expensive repairs to your system or avoid a sewage backup in your home. In many states, a septic system must be inspected with the transfer of real estate. However, it is not only when you are buying a home that these inspections are needed. Septic system inspections should be done every 1 to 3 years for as long as you own your home.
    • In general, an inspection will involve the following:
      • Review of the system permit, design, and installation records (including system age)
      • Review of the septic tank pumping and system maintenance records
      • Opening and inspecting all tanks (septic tank, pump tank, distribution box)
      • Evaluating the septic tank sludge and scum levels and determining the need to pump
      • Assessing the condition of the septic tank effluent filter (if installed)
      • Looking for signs of leakage, such as low water levels in the tank
      • Looking for signs of backup, such as staining in the tank above the outlet pipe
      • Evaluating the integrity of the tank, inlet and outlet pipes and looking for signs of corrosion
      • Verifying all electrical connections, pumps, controls, and wiring are intact
      • Possibly using a camera to look at solid pipes and leach lines for blockages or collapsed piping
      • Evaluating the drainfield for signs of system failure, such as standing water (surfacing) or unequal drainage
      • Possibly excavating parts of the drainfield to look for signs of ponding in the system or groundwater impacting the drainfield
      • Examining the distribution box for structural integrity and to make sure drain lines are receiving equal flow
      • Reviewing other available records on water use and required inspections, monitoring, and reporting to ensure system compliance with local regulations regarding function and permit conditions.
    • EPA’s Quick Tip Video walks through a typical inspection, “Protect It and Inspect It!”
    • Contact your local permitting authority (i.e., local health or environmental department) for a list of professional inspectors in your area.

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Last updated on March 31, 2025