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WLS-012 Guidelines for Maintaining a Non-Standard Septic System

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Version: 05/10/2023


To provide guidelines for the proper care of non-standard septic systems.


Maintenance related issues account for most of the problems associated with non-standard septic systems. Permit Sonoma recommends that the following routine maintenance be practiced to prolong the life of non-standard septic systems.

Maintenance Items

  1. Check the lids and/or risers of the septic tank and sump to make sure they are air and watertight.
    • If working on a riser, secure all required bolts.
    • It is recommended that risers be installed over the access ports of the septic tank to provide easier access for pumping and servicing.
  2. Pump septic tanks on average, once every 3-5 years.
    • Both chambers of the septic tank and the sump chamber should be pumped.
    • Ensure that the inlet and outlet tees of the septic tank are in place.
    • Effluent filters are required to be installed on the outlet side of all new septic tanks and can be retrofitted to older tanks.
    • If an effluent filter is present, it should be cleaned at least once per year. This can be achieved by removing the filter and hosing off the debris into the first compartment of the septic tank.
  3. Purge and adjust the lateral lines
  4. Check the alarm box function.
    • If the alarm box has deteriorated and is not operable, it must be replaced with a code compliant unit under permit and inspection by Permit Sonoma staff.
    • Ensure the dose counter advances whenever the pump is activated, and the pump operates when the test button is activated.
    • The alarm switch should always be in the “on” position and “sound” when activated.
    • An alarm that activates on its own is an indication of a problem with the system, and a licensed septic professional should be contacted.
  5. Check all toilets, faucets and showers for drips and repair any leaking fixtures.
    • Leaking plumbing fixtures can lead to hydraulic overloading of the septic system which may cause the system to malfunction and cause permanent damage.
    • Water conservation methods are recommended. These include:
    • Low-flow toilets, shower heads and faucets
    • Limiting shower use
    • Using fully loaded dishwashers and washing machines.
    • Garbage disposals should not be used as they cause debris to stay suspended in the tank and result in debris clogging the leach field.
  6. Keep all large animals and any vehicular traffic off the septic system and septic system expansion area at all times, especially when the ground is moist.
    • The impact of animals and/or vehicles may cause severe damage requiring repair or replacement of the system.
    • Compaction and erosion of the expansion area can occur resulting in the need to establish a new expansion area.
  7. For above ground systems, check for soil erosion resulting from seasonal rains.
    • Using a metal probe or shovel, measure the soil cover in suspected areas of erosion.
    • If there is less than six (6) inches of soil cover before reaching sand or gravel, fill those areas to bring the soil cover back to its natural shape.
    • Use soil of the same type and quality as the soil presently on the system.
  8. Always feather the soil on an above ground system so that it maintains a crown.
    • Soil should never be placed over the valve control or performance well box.
    • Access to these boxes must be always maintained to allow for sampling, evaluation, purging and adjusting of the system.
  9. If the area of erosion is large, it is recommended that a licensed septic system professional experienced with above ground systems be contacted.
    • Shallow trench pressure distribution systems also have a tendency for the soil cover to settle along the trenches where they have been back filled. If this occurs, soil must be added to bring the finished trench grade to ground level.
  10. Vegetative cover is recommended to prevent erosion of the soil over non-standard septic systems.
    • Vegetative cover also facilitates a natural means of evapotranspiration of the sewage effluent from the system.
    • Planting of a mix of perennial grasses, which are available in several types and mixtures, is recommended. Consult a landscape professional to find a compatible mixture.
    • Do not plant ice plant or ivy due to their highly invasive root systems.
    • For additional information, refer to WLS-017 Landscape Guidelines for Non-Standard Septic Systems.
  11. Ground cover should be routinely cut and properly maintained to further stimulate growth with minimal irrigation.
    • A drip irrigation system is not recommended but may be used in order to aid in the propagation of new plants.
    • Do not use an overhead (i.e., Rainbird) type sprinkler.
    • Compatible trees may be planted around the outside perimeter of the system at least ten (10) feet away from the system.
    • Non-compatible trees and shrubs could cause permanent damage to the system. Examples of these are:
    • Willow trees
    • Redwoods
    • Eucalyptus
    • Pepper trees
    • Other hydrophilic (water loving) trees  
    • For further information, refer to WLS-017 Landscape Guidelines for Non-Standard Septic Systems.
  12. Check the system for broken performance well caps and valve control boxes.
    • If needed, replace using plastic valve boxes with “Sewer” designated on the lid.
    • Never install wooden boxes.