Levin properties to undergo Waste and Stormwater inspections

Published on November 05, 2021

Thumbnail image for the Inflow & Infiltration Reduction Programme project.

Horowhenua District Council and the Horowhenua Alliance will be conducting inspections of wastewater and stormwater pipes and gully traps on properties in Levin to reduce the impact of misguided rainwater.

Every year Council carries out maintenance work and capital upgrades to ensure that the District's wastewater infrastructure remains in good condition.

Horowhenua District Council Water and Waste Services Manager, Asli Crawford says this includes conducting condition assessments to identify faults that could allow rainwater into the wastewater system. The sewers are designed only to carry wastewater; when stormwater gets into the sewers, it makes it more difficult and costly to treat the wastewater and reduces the capacity of the sewer pipes.

"During heavy rain, the wastewater treatment plants in the District can receive 2 to 4 times more flow than usual. In the long term, this means Council spend more money upgrading our treatment plants, as we treat millions of litres of wastewater that shouldn't require treating," explains Rukshan Basnayake, Three Waters Asset Planning Engineer.

Council will inspect the wastewater gully trap, which needs to be raised off the surrounding ground to ensure surface water can't flow into the sewer. We will also check downpipes from roof guttering to ensure the collected rainwater flows into the stormwater system, not the sewer.

"The gully trap should receive wastewater from inside your home, usually from the kitchen sink, laundry,  bathroom and toilets. When there is a blockage in the sewer, gully traps re-route wastewater outside of your home," Basnayake elaborates. The local wastewater bylaws require that the gully trap is at least 100mm above the surrounding ground (or 25mm if the surrounding land is a sealed surface).

The downpipe carries water from your roof and takes it to the local stormwater collection, which may be a public stormwater pipe, a soak pit or a water tank. The downpipe should not be connected to the sewer, and a downpipe feeding rainwater into the gully trap contravenes the HDC Wastewater Bylaw 2015.

"Council is running various projects to assess the condition of the public sewers in Levin and repair or replace pipes identified as potentially allowing groundwater into the sewer. However, it is the property owners responsibility to rectify issues with wastewater and stormwater collection pipes and gully traps on their property.  Properties that are listed for inspection will be notified via a mail drop, prior to inspection," Basnayake concludes.

Visit the Wastewater Inspections page for more info.

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