Wellington homeowner Stella Lawson had to spend $22,000 on having a council road dug up to repair her private wastewater pipes.

Homeowners are being stung with surprise bills running to tens of thousands of dollars because they are unaware it is their responsibility to maintain private wastewater pipes.

Wellington woman Stella Lawson found out the hard way when the bill to repair a pipe rocketed to $22,000 because she had to pay for part of Devonshire Rd in Miramar to be dug up and for contractors to operate stop-go signs while it was happening.

Industry body Water New Zealand says Lawson is not alone. Many Kiwi homeowners are oblivious to the fact that private sewer pipes are their responsibility to maintain – and inconsistent council rules do not help.

Lawson said she had an overflow in her toilet bowl about three weeks ago, which a plumber told her was caused by a collapse in the wastewater pipe connecting her house to the council main, known as a lateral pipe.

The collapse occurred about six metres from her house, in the middle of Devonshire Rd. But because Wellington City Council deemed lateral pipes to be the responsibility of homeowners, she had to fork out for the repairs and associated roadworks.

"The plumber said, in the nicest possible way, that the council gifted the city's lateral pipes to homeowners a few years back," Lawson said.

About $1500 of her total bill was the cost of taking the old asphalt to the tip, while $3000 was spent on having contractors manage traffic, and operate stop-go signs, for the two days it took to complete the work.

Lawson admitted she was surprised to discover a pipe so far from her property boundary was her responsibility.

Because the lateral pipe went beyond her property boundary she could not get it insured. If she had known it was her responsibility before she bought the house in May last year she would have had the pipe inspected as part of the due diligence of buying a house.

Lawson said Wellington City Council should probably have "come to the party" on some of the costs linked to the roadworks. She also felt it should be doing more to inform the public by including the state of wastewater pipes on Land Information Memorandum reports.

Water New Zealand chief executive John Pfahlert seconded the idea of including wastewater pipes on Lim reports, saying many homeowners did not understand the massive liability they faced.

"It's a large issue that not a lot of homeowners are aware of," he said. "They could potentially be facing repair bills of between $5000 and $10,000 without too much trouble at all."

Differing council rules across the country were partly to blame, Pfahlert said. Technically, all councils can legally force homeowners to repair private wastewater pipes right up to the council main, but some chose to bear the cost themselves.

In the Wellington region, the Wellington, Lower Hutt and Upper Hutt city councils all place the responsibility on homeowners as far as the council main, while Porirua City Council covers the cost of any repairs that extend beyond a property boundary.

Wellington Water spokesman Alex van Paassen said the organisation was aware the inconsistent rules were causing confusion, and it was considering whether a standard region-wide policy should be adopted.

Wellington city councillor Iona Pannett, who sits on the Wellington water committee, said she would ask council staff for advice on how to make homeowners more aware of their wastewater pipe responsibilities.

She was also "seeking information" last night on whether Lawson or the council was legally obliged to cover the cost of the roadworks.

THE 'GIFTING' OF WELLINGTON'S WATER PIPES

Private wastewater pipes have always been the responsibility of homeowners in Wellington. In 1992 the city council decided to fund their repairs in an attempt to improve the quality of natural streams and marine waters.

However, by 2004 the cost of funding this had increased by more than $600,000 a year, which was out of proportion with any benefits to council. So in 2005, the council agreed to shift the responsibility for maintenance and repairs back to homeowners.