Higher chlorination dislodges sediment
Horowhenua District Council has begun selective weekly flushes of its main water supply pipeline in Foxton, but still says a flood of water-quality complaints are mostly because of residents' own pipes.
Council water services manager Sarah Stephen said there had been 125 complaints about water quality at Foxton and Foxton Beach this year.
When investigated, "almost all" had turned out to be problems with the landowners' pipes, she said.
Residents previously spoken to by Fairfax have said they felt their concerns were not being heard by the council, and described the water as the colour of "cold tea" or "sewage", with a strong chemical odour and "grit" in it.
Stephen said the material in the water was dislodged from buildup inside pipes by recently increased levels of chlorination.
More chlorination had been used since water treatment processes were upgraded; in May last year for Foxton Beach, and May this year in Foxton.
Stephen did not know how long the problem would continue but said the water was safe to drink.
"The buildup is the same buildup you'll get in your shower if you don't clean your shower.
"It's an issue of old pipes; materials accumulate . . ."
Responsibility for the buildup and subsequent dislodgement into the waterflow did not lie with the council if it occurred in pipes it did not own, she said.
Residents are advised to run their taps for 10 to 15 minutes to flush the pipes on their side of the property boundary.
Only areas with a slow waterflow would be flushed each week but the council could include other areas if a series of complaints from concentrated areas were received.
The number of complaints and the degree of the problem at Foxton Beach seemed to have reduced since it arose in May last year, she said.
In May 2013 the Foxton Beach water supply was upgraded to improve the water supply from E grade, an unacceptable level of public health risk according the the Ministry of Health, to A grade. The same upgrade was done in Foxton in May this year.
The upgrades to the water supply cost $80,000 for each township, Stephen said.
Residents who had tried running their taps for 10 to 15 minutes but who found water problems persisted should contact the council, she said.