Frequently Asked Questions

Coffs Harbour City Council is initiating a Stormwater Inflow Reduction Project to reduce the volume of stormwater entering the sewerage network.  Stormwater inflow can be difficult to detect as it is not always obvious where the problem is occurring.

Council is embarking on a proactive program of visual inspection and smoke and dye testing of the sewerage system in residential, commercial and industrial areas across the Local Government Area.  The aim is to identify instances of illegal stormwater-sewer cross connections and other points of storm water ingress within the sewer network.

Council will be contacting residents to inform them prior to commencing testing and inspection work and any issues will be noted and letter sent to the owner to rectify the problem.

In most cases the cost to rectify an illegal connection will be minimal and property owners may be able to do the work themselves.  For those who can’t, a licensed plumber will understand the requirements and be able to assist.

During testing, Council workers and contractors may be required to enter your property (but not enter your house) in order to verify cross connections and conduct dye testing.  All Council officers and testing contractors will carry identity cards to confirm that they are authorised and represent Council.

Stormwater inflow is where storm water is able to enter the sewerage system directly through damaged or uncovered manholes, low lying or damaged gully traps and illegal stormwater to sewer connections. 

Infiltration is the flow of groundwater entering the sewerage network through damaged or deteriorated sewer mains, lateral connections and manholes.  Infiltration is harder to detect and usually requires additional visual assessment through camera inspections to locate the source of the infiltration.

The sewer system is designed to receive domestic sewage from residential and commercial properties and convey this to one of Council’s waste water reclamation plants for treatment prior to reuse or disposal. 

The design of the sewer reticulation system makes allowance for a small amount of stormwater ingress however, excessive inflow places significant strain on the network and can lead to environmental spills, public health risk and push pump stations and treatment plant operations to capacity.  In addition to the high operating costs incurred, it can lead to the need for premature and expensive upgrades, costs ultimately borne by the rate payer.

Common sources include low, buried or broken manholes as well as illegally plumbed stormwater systems from areas such as roofs, gardens, rainwater tanks, roads and drainage sumps.  Sometimes these connections lie underground so you may have inherited the problem or not be aware of where your pipes actually go.

You may not be aware that your property has an illegal connection between the sewer and the stormwater.  Often the connection lies underground and hidden from sight, however you can identify illegal connections at your property that are above ground.  If the outlet of the gutter downpipe from the roof or the overflow from the rainwater tank drains into or is directly connected to the gully trap you should contact a plumber and arrange to have the stormwater connection diverted.  

You can also identify any other possible areas of concern such as a gully trap that is at ground level and damaged, allowing direct runoff into the sewer when it is raining. 

This picture is of a correctly installed gully trap and another that is too low, allowing stormwater to enter.

Under the New South Wales Government Plumbing and Drainage Act 2011 any plumbing connecting stormwater drainage to sewer that does not comply with the Plumbing Code of Australia is classed as an illegal connection. 

The most common illegal residential connections are roof gutter downpipes, rainwater tank overflow, and drainage pits found in gardens and driveways connected to the sewerage plumbing of a residence.

Most common can be roof downspouts connected directly to the gully trap, or low lying or damaged gully traps allowing stormwater to drain to them.  A visual inspection of your property may quickly show if you have an improper connection.

Council can provide helpful advice for you to determine if a connection is illegal.

For assistance or advice please contact Council

It is important to set up your stormwater and sewer system separately.  Water from rainwater tanks, roof gutters and storm drains must not be connected to the sewer. 

If you find a connection, it must be disconnected and diverted to either the street water table (kerb) or onto your own land.

Please contact Council or your plumber for more advice.

Smoke testing is a relatively simple process that consists of blowing a non-toxic smoke mixed with large volumes of air into the sewer, usually introduced through a manhole. The smoke travels the path of least resistance and quickly shows up at sites that allow surface water inflow. Smoke will identify broken manholes, illegal connections including roof drains, sump pumps and yard drains, uncapped lines and even will show cracked mains and laterals, providing there is a passageway for the smoke to travel to the surface.

Dye testing is when a liquid dye is sent down a stormwater downpipe from a rooftop of a property while an inspector observes the flow of wastewater through a manhole.  If the dye is present it indicates a defect or illegal connection to the sewer.

Smoke should not be able to enter your home – if it does, this may indicate defective internal plumbing.

If smoke does enter your home then the defects could also allow sewer gases to enter your home which are a potential health hazard.  Property owners should contact a licensed plumber to investigate and rectify these defects straight away.

(Please note – the smoke used in testing is odourless and completely harmless to people, plants, animals and the environment and will dissipate quickly with normal ventilation)

• Ahead of testing you will receive multiple notifications, including a letter box drop 24 to 72 hours before smoke testing work begins in your area
• Please provide clear and safe access to the outdoor areas of your property and ensure that pets, particularly dogs are restrained
• If you need to make special arrangements for our visit, for example if you have a security system or locked gates, then please email us.
• Areas identified as contributing the most to stormwater inflow are being tested first.
• Coffs Harbour Police and Fire Service are aware of the smoke testing areas and schedule
• You do not need to be home during the smoke testing work.  This will be undertaken by contractors on behalf of Council who will carry identification cards that must be produced on request.
• Testing will be carried out Monday to Friday between 8am and 5pm
• There should be no interruptions to sewerage services for customers as a result of these works and customers can use their taps, toilets etc. as normal during inspections.

Council can apply fines and issue maintenance orders to property owners who have illegal storm water connections to sewer, however Council would prefer to work with residents to overcome the problems as they are found.  Council understand that in many cases the connection may have been made before the current owner purchased the property, or was unintentionally connected.  As such we will be contacting the owners of properties that have been identified as having illegal connections and attempting to rectify the issue

By reducing stormwater inflow into the sewer, Council can continue to provide a cost effective service to residents.  If nothing is done about this problem, it will lead to increased operating costs and expensive capacity upgrades, the costs of which are ultimately borne by the ratepayer.

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.  Property owners are therefore asked to be proactive and review stormwater connections prior to the smoke and dye testing and to rectify any problems as soon as possible after they have been identified.

You can contact the council directly by phone with any questions regarding the Stormwater Inflow Reduction Project on 02 6648 4000, or go to the Coffs Harbour City Council website: https://haveyour.say.coffsharbour.nsw.gov.au/Reducing_Stormwater_Inflow and follow the links for more information.  There will also be regular updates on Council Facebook and Twitter feeds to inform you where and when the smoke and dye testing is scheduled.