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Wastewater system maintenance

Whether you choose a standard septic system, a community wastewater management system or an aerobic wastewater system, the system will need to undergo a settling in period in which the required bacteria establish themselves. During the first few weeks of operation, there may be some odour associated with the tank from vents in the system. This is normal, the odours should reduce once the tank has settled and the necessary bacteria is established.

For a waste control system to function efficiently the tank needs to operate under alkaline conditions. Under normal operation the tank will be in an alkaline condition, however, the balance of the tank can be compromised due to:

  • Excessive use of cleaning chemicals.
  • Shock volumes of incoming water from washing machines or spa baths.
  • Lack of use of the system if the house has been vacant for some time.
  • Allowing sanitary napkins, facial tissues, disposable nappies or similar items to enter the tank.

Everyone has an important role to play in keeping both the SA Water and Barossa Council sewer systems working. Sewer systems operate as an entire unit life cycle, so what goes in your sewer drains at home affects everyone.

SA Water has more information on Why what you flush matters.

Odour problems

If conditions in the tank become acidic the normal bacteria may die off which will result in offensive odours. This can be rectified by using hydrated lime which is available from hardware stores. It is recommended to mix 0.5kg of lime with 10 litres of water, which can then be flushed down the toilet 2 or 3 times a day, for 3 to 4 days, until a total of 5kg is used. The balance of the tank should return in about a week. If odours are still present after that time more lime may be required.

General system maintenance tips

Mosquito Control

  • Ensure vents have mosquito-proof mesh fitted.
  • Ensure inspection openings and tanks are sealed to prevent mosquito entry.


  • Use only products labelled as biodegradable or ‘safe for septic tanks’.
  • Follow directions for use and use only in moderation.
  • Where possible use alternative cleaners such as bicarb of soda, borax, vinegar etc.

Toilet Paper

  • Use only a biodegradable toilet paper. Facial tissues, sanitary napkins, tampons, flushable wipes and disposable nappies should not be flushed down the toilet.

Food Scraps

  • All food scraps should go in your domestic waste bin or compost, please do not put them down the sink.


  • All types of septic systems require desludging by professional contractors at least every four years. Some tanks may require pumping out more frequently depending on the size of the tank and whether it is for domestic, industrial, or commercial use.

Prohibited Discharges

  • Stormwater from downpipes or rainwater tank overflows.
  • Trade waste from commercial premises.
  • Backwash waste from swimming pools/spa pools.
  • Paint, petroleum products or other solvents, strong alkalines or acids.

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