Stormwater and the sewer system

Sewage (or wastewater) is the used water that comes from your kitchen, bathrooms, laundry, sinks or other plumbing components in your home. Sewer systems collect, treat and dispose of the sewage from our homes and businesses.

Stormwater systems are made up of gutters, downpipes, pits and drains which collects any water which runs off a site due to rainfall. Stormwater systems manage rainwater run-off from our streets and roofs. Stormwater should never be plumbed into the sewer system as this can cause serious overflows. 

There are two ways for stormwater to get into the sewer system:

Infiltration

• Cracked pipes – usually caused by tree roots or movement in the ground.
• Inspection Holes– poorly fitting, cracked or broken inspection holes can let water into the system. If you notice any problems, contact Shoalhaven Water directly.
• Broken Pipes– broken pipes can occur in both Council’s sewer systems and on private property. Whilst Council maintains the mains, as a property owner it is your responsibility to maintain the pipes on your land. Broken pipes not only let stormwater in, but they can also cause a health impact on the environment. Contact a licensed plumber immediately.
• Boundary Traps– are inspection points in the sewer system and mark the place where your system joins Council’s mains. Damaged or cracked lids and/or concrete rims will allow unwanted stormwater water to enter the system. There will also be a problem if the vertical riser (the pipe under the boundary trap) is cracked.

Inflow

• Low-lying yard gully – these are found just outside your house and generally have a loose-fitting grate that comes off easily in the instance of a sewer overflow. If the gully is low-lying in the ground, then it can let large amounts of stormwater into the sewer system. A plumber can raise the gully or lower the ground around it.
• Direct connection – stormwater pipes directly connected cause excess water in the sewer system resulting in overflows of raw diluted sewer further down the system.

An overflowing sewer can be unpleasant and anyone who has had the experienced usually remembers it. Sewer overflows effect everyone, they cost money to clean up and they damage our environment. By working together, we can help keep stormwater out of the sewer system.

As a property owner you are responsible for maintaining the internal pipes on your property so that stormwater doesn’t leak into the sewer system.

If you are unsure if stormwater is getting into your internal sewer system, there are a number of tests that can be conducted to find where potential issues may be including:

• Camera investigation – a remote-control CCTV camera can be inserted into the pipes to check what condition they are in; and/or
• Smoke testing – which is non-toxic smoke directed into the sewer pipes and typically smoke will come out of any inappropriate connections or breaks to pipes.

Contact a local plumber to conduct these inspections.