22 May 2013

Smoke testing Rotorua sewers to begin next week

As part of an improvement programme to reduce the amount of stormwater unnecessarily entering the district’s sewer system and being treated, Rotorua District Council (RDC) is embarking on a programme to smoke test sewers across Rotorua.

Testing will begin late next week around the Elizabeth Street area, and continue indefinitely throughout the urban area.

RDC Utilities operations manager, Eric Cawte, said smoke testing works by injecting pressurised smoke into localised sewer pipes which are then monitored.

“If smoke appears on the surface it indicates cracked sewer pipes, broken private drainage or cross connections from downpipes, and means stormwater may be able to enter the sewer system. This extra water in the sewer can unnecessarily increase daily flows through the waste water treatment plant by millions of litres a day.

“But it not only costs the council and ratepayers a lot of money for wastewater treatment but increases the likelihood of overflows, meaning environmental and public health risks.

“Once any points of stormwater entry have been identified, they would need to be repaired by council on public sewers or by the owner if the fault relates to plumbing on private property. By eliminating this extra water from the sewerage network, there will be huge savings in treatment costs, as well significant improvement in Rotorua's sewer infrastructure.”

Mr Cawte said residents will be notified by mail about the date testing would take place in their areas and reminded again through a letterbox drop notice 24 hours in advance of the work starting.

“In the very unlikely event that smoke enters a house, locals can be reassured that the smoke is non-toxic. However if smoke does appear, people should double-check to make sure it is not actually coming from a fire at their premises.

“The smoke we are using has only a light odour and does not leave any residue. It’s similar to the harmless smoke used on stage in theatre productions, and is safe to humans and animals for short term exposure.

“The smoke is bright white, and during testing it will be often seen coming from vent pipes on rooves, as well as possibly from external gully traps, and from the ground in some instances.”

However if anyone has any concerns at all, they can make contact with the council on 07 348 4199 or email smoketesting@rdc.govt.nz.

ENDS

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