Media release

Media release: Pollutants in stormwater drains identified

Friday 22 July 2022

The recent downpour and flooding has prompted the Otago Regional Council to remind people of their obligations around discharges into stormwater drains, following instances of pollutants recently entering drains.

ORC Manager Compliance Tami Sargeant says there have been cases of inadequate controls during the past few days which lead to harmful pollution of Otago’s environment.

“We’ve come across a number of stormwater discharges this week, due to the consistent rainfall,” she says.

Kerbside drain


“The priority here is for people and businesses to check that sediment controls are in place and stormwater drains do not have contaminants going into them.”

More than 30 complaints of sediment discharges to water or stormwater pollution have been received by the ORC pollution response team during the last two weeks. The complaints are mainly in Wānaka and
Dunedin, but also in the other districts.

A priority is having good sediment management practices already in place at earthworks sites.

Mrs Sargeant says some of the discharges were from consented development sites, small residential worksites which are unconsented, roadworks maintenance, oil changes on roads and from the washing down of concrete pads.


Check sediment controls are working

“We’re encouraging people to install sediment controls and to check that they’re actually in working order. They should also be aware of the stormwater rules,” she says.

“If the right controls aren’t in place, heavy rain can carry sediment from earthworks into our waterways,” she says.

While acknowledging that during high-flow events some sedimentation occurs naturally, the sediments flowing into streams, lakes, and the coastal environment can be harmful for freshwater and marine ecology, she says.


High risk in residential developments

She says some of the highest risk areas are around residential developments, and developers must adhere to their consent conditions.

“There must be suitable erosion and sediment controls in place before earthworks begin, so as to minimise the risks of pollution,” she says.

If people are unsure about the rules around earthworks, they should contact ORC’s consents team by emailing, or calling 0800 474 082.

If liquid paint or plaster, cleanup washwater and solvent wastes make their way into the stormwater drain, the chemicals they contain can kill aquatic life, Mrs Sargeant says.

Using lawns, gardens and gravel areas are good way to soak up and filter runoff from household activities, she says.

More household tips.

Anyone seeing pollution around Otago should contact the 24/7 ORC pollution hotline on 0800 800 033, or email


Stormwater drains and polluted waterways