Septic Tank Requires Frequent Emptying


If your septic tank is overfilling and you need to empty it more than once a year, it is most likely that the soak hole or trench percolation area is blocked and is causing the effluent to effetely back-up to the dwelling. The reason for this varies from site to site but the main causes are:

  • Poor or inadequate design or installation.
  • No site assessment report or percolation test competed.
  • The old septic tank design being incapable of handling a modern dwellings discharge of daily showers, washing machines and dishwashers.
  • Lack of frequent emptying / desludging to reduce the sludge content in the septic tank.


The average septic tank should only require emptying every 1 to 5 years as per the chart below.

If the septic tank is backing up, unfortunately in most cases the damage is done and the septic system will need to be upgraded or replaced.

Firstly a site suitability assessment will be completed at design a new system taking into account all the unique features on the site, followed by installation.



Guide to emptying intervals:

Number of full time residents 2 4 6 8
Pre-1990’s Septic Tank Emptying Frequency 3 years 2 years Annually 9 Months
Post-1990’s Septic Tank Emptying Frequency 5 years 4 years 3 years 2 years

Please note: These are generic guidelines only and homeowners should always consult the individual sewage treatment system manufacturer to insure they are emptying and maintaining their sewage system correctly.