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Government reforms to address New Zealand’s housing crisis will ease building restrictions on minor dwellings and granny flats up to 70sqm, but experts warn that without a clear wastewater plan this could create serious environmental problems.
A Waterflow NZ spokesperson said the impact of intensifying housing, especially in rural and peri-urban areas not connected to council reticulation, didn’t come from the walls or roof, it came from the extra wastewater.
“The framework around wastewater is still fragmented. Each council has its own unitary plan, its own interpretation of standards and different levels of enforcement. If we don’t align around a national approach, we risk undermining the very environmental protections that wastewater systems should be designed to uphold,” they said.
“We already have a solid technical foundation in the AS/NZS 1547 (the standard for on-site domestic-wastewater management). It’s widely used by professional wastewater designers and approved by all councils.
“But as more small dwellings go up, and more non-specialists get involved in installation or consenting, there’s a real risk of corners being cut.”
Onsite wastewater management systems special interest group chair Caleb Pirini said people often thought of wastewater as a simple tick-box exercise.
“But the difference between a well-designed system and a poorly-designed one can be the difference between protecting groundwater and polluting it. That’s why design and oversight can’t be watered down in the rush to build.”
WaterFlow general manager Ken Hoyle said he had seen firsthand what happened when wastewater systems weren’t designed or installed with care.
“Without a robust process in place, the risk of widespread failure is very real. When shortcuts are taken problems might not appear straight away, but they almost always surface later – and on a much larger scale,” he said.
Resource Management Act Reform Minister Chris Bishop and Associate Housing Minister Tama Potaka said addressing housing affordability and supply was a key focus for the government.
“We’re proposing to introduce a consistent national framework – called National Environmental Standards (NES) – that will reduce consenting inconsistencies, remove planning barriers and make consenting less costly and complex.
“We want to make it easier for families to build a granny flat of up to 70m2 on an existing property through proposed new NES for granny flats. This NES will require all councils to permit a granny flat on sites in rural, residential, mixed use, and Maori purpose zones without the need to gain a resource consent subject to certain conditions.
“It will sit alongside our parallel work to amend the Building Act to remove the need for a building consent for those same granny flats.”
