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Maintaining your septic system

Common problems with septic systems

  • Too much sludge can block up disposal pipes.
  • Too much wastewater can cause solids to be pushed into the pipes and block them. This often happens if there is more wastewater coming in than the septic tank is designed for.
  • Toxic chemicals (like bleach or commercial cleaners) entering the system. These chemicals can kill off the good bugs and stop them breaking down waste.
  • The mechanical parts of mechanical treatment plant septic systems can breakdown and cause the system to stop functioning.
  • The disinfection stage of mechanical treatment plant septic systems can breakdown if not maintained. This can result in waste water being unsafe.

Signs of a problem with your septic system

  • Water draining away too slowly from sinks, bathtubs and showers.
  • Gurgling pipes when water is draining.
  • Sewage smells.
  • Water pooling around the disposal area .
  • Grass is unusually green above the septic system outlet.

Prevent problems by maintaining your septic system

To keep your septic system working well there are things you should and should not do.

What you should do

  • De-sludge every 3-5 years (frequency depends on use).
  • Refill with clean water and add a handful of lime after every desludging (this helps good bugs and reduces odour).
  • Hire a licensed plumber to look at sludge and scum levels as well as blockages.
  • Keep a record of all system maintenance.
  • Make sure the tank lid is in place to stop mosquitos from breeding.
  • Spread out your laundry cycles to decrease stress on the system.
  • Grow suitable plants over the drainage field.
  • Have your mechanical treatment plant septic system serviced by an accredited servicing agent once every three months.
  • Have an alarm installed on your mechanical treatment plant septic system by an accredited servicing agent. This will warn you if the system malfunctions.
  • Maintain the disinfection chamber of your mechanical treatment plant septic system. Chlorine tablets need to be properly fitted to the dispenser and UV light tubes need to be cleaned regularly.

What you should not do

  • Put rubbish down the toilet.
  • Modify your tank or plumbing without council approval. Your septic system has been designed for specific amounts of sewage per day and alterations can create more problems than they solve.
  • Allow vehicles to drive over any part of the system.
  • Allow stormwater to discharge into the septic tank or over the disposal field.
  • Cover the tank or drainage field with paving, concrete, building structures etc.
  • Place non-biodegradable objects into the system.

More resources

For more information, please read our septic tank maintenance fact sheet.

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