Stormwater Intrusion

What is stormwater intrusion?

Stormwater intrusion is where stormwater has been allowed to flow into a septic system. This is illegal under the Plumbing Code and the Department of Health Waste Control Standards. Under these regulations all excess rainwater collected from areas such as roof, gardens, roads and rainwater tanks need to be plumbed away from the septic system.

Why is stormwater intrusion a problem?

Council operates a Community Wastewater Management System (CWMS) in Port Augusta and Stirling North areas which treats the effluent from septic tanks via a network of pipes leading to a centralised treatment facility in Port Augusta. Some people may know this as a STEDS scheme.

When it rains, excess water enters the system resulting in an increase in the amount of water to be processed and is creating an ever increasing nuisance and overflows within the Councils CWMS System.

Where does the excess stormwater come from?

Common sources include illegally plumbed stormwater systems from areas such as roofs, gardens, roads and rainwater tanks. Much of the problem also lies underground so you may have inherited the problem or not be aware of where your pipes actually go.

What does this mean to you?

Stormwater that is connected to Council’s CWMS network is classed as an illegal connection.

Excess water entering the system results in overloading of the pipe network, higher running costs, call outs due to high level alarms and unnecessary strain on the treatment systems. At worst, overflow of the system can occur into private properties or other waterways.

In addition to this is the unnecessary cost and processing of treating stormwater which the system is not designed to accept.

Higher running costs can also result in less funding available to maintain and upgrade other areas which can result in an increased operating and maintenance charge to ratepayers.

How do I know if it’s set up properly?

You may have bought your house without knowing how your stormwater system was previously connected illegally to your septic system or the associated pipework (by using outside gully traps or inspection points to dispose of stormwater).

The diagram below shows how connections may be placed.

diagram showing illegal connections described above

What not to do

The most important thing to remember is not to have any rainwater or stormwater connected to pipes that go to septic tank systems or to sewer drains.

  • DO NOT connect rainwater to sewer drains
  • DO NOT connect stormwater to septic tanks
  • DO NOT connect stormwater downpipe discharges to gully traps.

How can I fix it?

It is important to set up your stormwater and septic system separately.

Water from rainwater tanks and storm drains must not be connected to a septic system.

If you find stormwater connected to your septic system, it must be disconnected immediately and diverted to either the street water table (kerb) or onto your own land.

Please contact Council or your plumber for more advice.

What is Council doing?

Stormwater intrusion may be difficult to detect as it is not always obvious where the problem is occurring. As part of the ongoing maintenance of the Council CWMS, Council will be monitoring these specific areas of concern and may include, but not limited to

  1. The dosing of the drains to detect illegal connections in these areas.
  2. Undertaking a visual inspection of these properties affected.

Council’s main aim is to identify where illegal pipe connections exist and to advise the owner(s) to rectify the problems. Any issues will be noted on a ongoing basis. Generally the illegal connections are easily rectified with minimal costs to the owner.

Can I receive a fine from Council?

Council can apply fines to the owners of properites, who have illegal connections to the CWMS, however, Council would prefer to work with residents to overcome problems as they are found. By reducing stormwater intrusion into the CWMS, Council can continue to provide a cost effective service to residents. If nothing is done about this problem, it will lead to higher than normal increases in the annual CWMS operating and maintenance charge, due to increased operating costs.

Your understanding of the issues associated with stormwater intrusion and your willingness to be part of the solution will benefit everyone who uses this service.

For further information and advice please contact Council on (08) 8641 9100 during business hours.