The city faces the possibility of being prosecuted by the regional council after the city's building inspectors overlooked plumbing problems at the Orchard Grove subdivision, resulting in a creek popular with children being contaminated by human waste.
Regional council director of resource management Selva Selvarajah yesterday said the inspectors should have been more stringent, while the city's development services manager Kevin Thompson insisted the fault was not common, and said Dr Selvarajah was "right out of his area of expertise" and had "overstepped the mark".
The regional council is investigating the contamination of the waterway, after complaints from residents who discovered sewerage pipes at two homes had been mistakenly connected to stormwater drains.
The errors, which occurred 18 months and six months ago, went undetected until two weeks ago, during which time raw sewage fouled the nearby creek - a popular play area for neighbourhood children.
Mr Selvarajah told the Otago Daily Times water samples were taken yesterday to check for faecal bacteria, and laboratory results were expected within days.
Staff would also prepare a report on the contamination before a decision about whether to prosecute was made.
The report was expected to be completed in several weeks.
Asked if he was surprised DCC inspectors had missed the plumbing fault, Dr Selvarajah said: "I am, yes."
Connection problems were "one of the major issues" dealt with by local authorities' building inspectors around New Zealand, he said.
"This is the modern era and I would have thought there are better techniques," he said.
"You would have thought their approach would have been more stringent."
When contacted, Mr Thompson responded: "He's not an inspector - he's nothing to do with how drainage is connected up. I would have to say he's overstepped the mark."
Mr Thompson said there were no plans to re-examine the city council's building inspections process.
Dr Selvarajah said once the regional council's report was completed, options ranged from taking no action, to issuing an infringement notice, to launching a prosecution.
Dr Selvarajah said a simple test, such as pouring an eco-friendly dye down a toilet and checking where it emerged, could have identified the fault if there had been doubts about the connection.
Responsibility for such a check would be with the city.
Mr Thompson said city staff would use such a test only when there were doubts about a connection, and "we had no reason to doubt the connections".
One homeowner spoken to yesterday, who did not want to be named, doubted the regional council tests would detect contamination, as plumbers had returned to fix both faults, late last week and on Monday.
He believed the city council should take responsibility for missing the plumbing fault in the first place: "They signed our code of compliance certificate," he said.
The plumbing company responsible for connecting the first home was yesterday named by the homeowner as Adams Plumbing and Drainage, a Mosgiel-based firm employing up to 60 staff in Dunedin and Central Otago.
Repeated efforts to contact the company's owner, Chris Adams, were unsuccessful yesterday.
He did not return calls.
