Your on-site effluent treatment and disposal system is probably quite near to your house. It is important to know the location of your system so regular maintenance and repairs can be carried out. When you locate your treatment and disposal system, draw a rough sketch map showing your house, the treatment system, the disposal system and any permanent features on your property. Keep the map with your other household documents.

Locating your septic tank

• First look for a “mushroom vent” sticking out of the ground, or the access lid if it is not covered with grass. If you cannot see an access lid, look for a mound or dip in the ground by the mushroom vent, or a place where the grass is a bit thinner than elsewhere. Following the effluent pipe from your house will also help, and if necessary, you can probe the soil with a metal rod.
• If you are not the original owner of the house, then locating the disposal system can be more difficult. It will usually be downhill from the house and treatment system. The trench/bed system may have vents at the end of each disposal pipe which will be above ground, or its location will be apparent because the grass along the soakage lines is usually greener during the summer months. Alternatively, you may need to probe the back yard with a metal rod to locate it.
• If you have no luck, phone a drain layer or your District Council’s plumbing and drainage inspector. The District Council may have a drainage plan for your property.

AWTS and other mechanical treatment systems

Your system is likely to have one or more of the following above ground level that are close to the treatment system and will allow you to locate it:

• An electrical box; or
• Part of the treatment system that allows easy access for maintenance;
• An air pump that supplies the aeration chamber; or
• A high effluent level warning system (either a light or alarm).

The irrigation line disposal system should be easy to see if it has been installed within an ornamental garden. The lines should also be easily located by the flushing valves at the end of each line which will be above ground. If the irrigation lines are not easy to see, then you will need to contact the maintenance contractor for the system, as they should have plans of its location.