Manukau Water targets illegal waste flows

Manukau Water Limited is cracking down on illegal connections to its wastewater system, after recent surveys showed some people have been putting public health at risk by flouting building laws.

Recent surveys have found a significant number of faults in private drainage systems in Manukau, which are allowing stormwater into the wastewater system. In some areas as many as 1 in 20 homes have such faults, which can lead to pollution of the environment and have been known to cause serious illness.

Manukau Water Limited chief executive Raveen Jaduram said inflow and infiltration into the wastewater system is a potentially serious problem, and Manukau Water Limited has therefore launched a programme requiring property owners to rectify such faults.

Mr Jaduram noted that in periods of heavy rain, a sudden increase of water flowing into the sewerage system can result in overflows, which can lead to contamination of private properties and watercourses. The excessive flows can also lead to reduced levels of treatment at wastewater treatment plants due to system overloading.

“This is potentially a serious risk to public health and a lot of the problems are due to properties not meeting building requirements. Where this is found to be the case we will be requiring property owners to fix the problem,” he said.

Manukau Water Limited is inspecting properties that might be at risk., and where it has detected a serious fault it is writing to property owners and giving them 20 working days to fix the problem.

“Our aim is to inform customers of the possibility of rainwater inflow and infiltration into the system, and to help prevent this by inspecting properties that might be at risk. Where a fault is detected it will need to be corrected. This might require the services of a builder, plumber or drainlayer,” Mr Jaduram said.

Where properties owners do not fix the problem, Manukau Water Limited’s contract allows it to restrict or disconnect, where permitted by law, the supply of its services to a property in order to protect public health.

“We could also rectify the problem and recover the cost of doing so from property owners, or we could notify local government authorities of a property’s non-compliance, which could be an issue for a property owner if, for example, they wanted to sell their property,” Mr Jaduram said.

The company has already conducted testing in the Spinnaker Bay area of Manukau and parts of Howick.

It will carry out further tests throughout Manukau including inspecting private drainage such as gully traps, down pipes and manholes. Manukau Water Limited will also undertake smoke testing of wastewater pipes, using a small machine to blow smoke into sewer pipes. This smoke is white, cold, non-toxic, non-irritating and completely harmless. It allows inspectors to see if stormwater can enter the wastewater system. If the system is working properly, the smoke will be released from ventilation points in the system but if the smoke discharges from downpipes or other points it will identify a problem that requires further investigation.

Property owners will be advised by letter prior to the testing actually taking place on their property.

Mr Jaduram said Manukau Water Limited encourages all property owners to ensure appropriate devices are installed to prevent inflow and infiltration into the sewerage system, and to regularly check pipes, drains and gully traps on their properties to make sure they are free of blockages.