Stormwater drains

 

Save the drain for the rain

Oil spill in Whāngārei's town basin.An incident where 50 litres of oil escaped through a stormwater outlet and ended up in Whāngārei's town basin.

Stormwater drains help carry away the rain water than runs off places like roads, rooftops, yards, carparks and footpaths.

Unlike what goes into our sewerage network, stormwater isn't treated – so what goes down the drain ends up in our streams, rivers and harbours.

Putting anything other than rain water in a stormwater drain can be a serious source of pollution (and it's also illegal).

This brochure provides information on how you can keep pollutants out of our stormwater systems, including alternative ways to dispose of your household wastes.

Stormwater drains are designed for rain water only

Drain on street.What goes in here... Stormwater outlet on beach....comes out here.

The cost of stormwater pollution

Each year the regional council responds to many cases of stormwater pollution. As well as the environmental cost, there's also the financial cost of investigation and clean-up – and that can be significant.

The incident shown on this brochure's cover – where 50 litres of oil escaped through a stormwater outlet and ended up in a harbour – cost an estimated $10,000 to deal with.

Fortunately, there are some simple things you can do to prevent pollutants reaching our stormwater systems and reduce the cost of stormwater pollution in Northland.

Stormwater or sewage?

Sewage gets treated, but stormwater doesn't – to avoid putting pollutants into our stormwater system it's important to know the difference.

Stormwater drain pipe.Stormwater

In areas with stormwater systems, domestic stormwater drains take away water from the outside of the house (like roof spouting or the yard). These drains may be at ground level for yard rainwater drainage, and the water inside should be clean with no bad smell.

The drains you see on roadsides and in places like parks, sports fields and car parks are generally stormwater drains. 

 

Sewer gully trap.Sewage

Wastewater from the toilet, bathroom, kitchen and laundry generally goes into a sewerage system or septic tank, via a domestic sewer gully trap.

Domestic sewer gully traps should be raised above ground level, to stop surface water going in, and the water inside may be smelly or dirty.

 

 

Common stormwater pollutants

HOUSEHOLD CHEMICALS

Why they're a problem: Car wash water and other common household chemicals can change the pH of our natural water bodies and harm aquatic life by burning and irritating their sensitive tissues. These products can also poison aquatic life, suffocate animals and plants by reducing oxygen concentrations in the water, or promote algae growths.

In rare cases, some hazardous chemicals can create gasses within the drainpipe which can explode, leading to injury, damaged plumbing, or drain blockages.

What you can do: When washing the car, try to do it on a lawn area where the wastewater can soak into the grass rather than flow into a stormwater drain. Dispose of unwanted household chemicals at a hazardous waste drop-off centre.

For a chemical spill, if it can't be safely absorbed with kitty litter, report it to the regional council's Environmental Hotline (0800 504 639) or the NZ Fire Service.

PAINT

Paint discharge from stormwater.Why it's a problem: Paint can be poisonous to our aquatic environments and to any creatures that it comes into contact with. It can also decrease light availability to aquatic algae and plants.

What you can do: Disconnect your downpipes before painting the roof. Small amounts of unwanted paint can be left to dry in the can then disposed of with your household rubbish. Small amounts of wash water can be diluted with water and tipped on the lawn. For larger amounts of paint, check if your local paint shop will take it; otherwise take it in a sealed container to a hazardous waste drop-off centre. 

FUEL AND OIL

Oil in water.Why they're a problem: Small amounts of fuel or oil can pollute a huge area, killing wading and surface-dwelling birds and fish and prevent oxygen from entering the water. These can contain heavy metal compounds and cancer-causing products which can build up in fish and shellfish that we may eat.

What you can do: Keep your vehicles free of leaks, and dispose of old and used oil at authorised disposal areas such as a hazardous waste drop-off centre. Do your oil change where accidental leaks can be easily cleaned up and accidental spills won't run into a stormwater drain.

 

DIRT AND SOIL

Dirt from stormwater in waterway.Why they're a problem: Dirt and soil may seem harmless, but it can be a serious pollutant. It can smother streams and riverbeds, reduce light availability to aquatic algae and plants, increase bacteria and reduce the oxygen concentrations that aquatic life depends on for survival.

What you can do: Keep sealed surfaces clear of dirt and sediment build up.

When washing paved areas, direct the wash water on to lawn areas where it won't run off into stormwater systems.

LITTER

Why it's a problem: Litter is easily swept into stormwater drains, and some of it remains in our aquatic environments for many lifetimes. It can harm aquatic animals if they eat it or get tangled in it. It also ends up on our beaches and along our streams and rivers – no one wants to see our coastline and waterways covered with rubbish.

What you can do: Put litter where it belongs – in the rubbish bin.

Household hazardous waste drop-off centres

The options listed below are only for household hazardous waste (not for hazardous waste from businesses, industries or farms).

Whāngārei district – Re:Sort Transfer station on Kioreroa Road.

Far North district – the transfer stations at Kaikohe, Whangae, White Hills, Taipā, Kaitāia, Opononi, Russell, Ahipara, Houhora and Whatuwhiwhi take household hazardous waste. Alternatively, contact the Far North District Council on 0800 920 029 for disposal options.

Kaipara district – contact Kaipara District Council on 09 439 3123 for disposal options.

Reporting stormwater pollution

Stormwater pollution can seriously harm the health of our waters and aquatic environments.

If you see any potential pollution to stormwater, report it to our 24/7 Environmental Hotline on free-phone 0800 504 639.

Stormwater outlet on coast.