Sewer systems `failing in HB'

Marty Sharpe
Wastewater systems designer Dave Miller has warned Hawke's Bay plumbers and residents that sewerage systems in the region are failing at a level comparable with the leaky building syndrome.
Hawke's Bay Regional Council, which monitors the systems, disputes Mr Miller's claims, published in the national Journal of Master Plumbers, Gasfitters and Drainlayers, and says wastewater system manufacturers and installers are working with the council to respond quickly to any failure.
The council intends to approach the journal's editor to ask why they had not been approached for comment.
Mr Miller, who designs and sells sewage-treatment systems, claims there are several treatment systems in the region that are not treating the sewage any better than a septic tank.
Because the manufacturers of these plants tell buyers that the effluent is clean, the public treat the effluent as harmless, Mr Miller said in the journal.
About 10 different treatment systems have been installed in Hawke's Bay. Mr Miller does not say which ones are prone to failure.
"Effluent from sewage treatment systems is often used to irrigate the section around the house, which the family uses and where children play."
Mr Miller warns plumbers that they may be held liable for the consequences of one of these systems failing.
He also raises the prospect of plumbers losing their own homes to settle awards or cover debts.
A Hawke's Bay Regional Council study early this year found that 75 percent of the household sewage treatment plants installed in Hawke's Bay's coastal settlements since 2001 had failed to meet the council's effluent standards.
Since April 2001 the council has required any sewage discharge to hold a resource consent if it is in an unsewered area that is zoned for residential purposes.
This includes sites above the Heretaunga Plains unconfined aquifer and coastal settlements such as Waimarama, Mahia, Haumoana, Te Awanga and East Clive.
Systems installed before April 2001 do not need resource consents, but must meet certain conditions.
Hawke's Bay Regional Council environmental regulation manager Helen Codlin said the systems were monitored when installed and again within two to five years.
The monitoring rules were likely to change when the council completed its Onsite Wastewater Review next year.
One brand of system has consistently failed compliance tests over the past three years. These are being upgraded at the manufacturer's cost. "Of the very few which council identified through its monitoring may pose a health risk, the risk was related to inadequate construction of the land application field, rather than the treatment system itself.
"Even if the effluent quality was meeting design performance, the health risk would still have existed," Ms Codlin said. In these instances the system must be repaired by either the landowner, or the installer.
A system may fail due to poor effluent quality, in which case it would be the landowner's responsibility, or due to construction, in which case it may be the plumbers responsibility.