Pollution entering stormwater drains can flow untreated into streams, waterways and coastal waters, affecting water quality and the habitat of marine plants and animals. People’s health may be affected if they eat contaminated marine plants or animals, or swim in polluted coastal waters. People need to know what activities introduce waste, contaminated water and rubbish into drains so they can avoid polluting our waterways.
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If pollutants get into stormwater drains they flow untreated into our streams, waterways and coastal waters. These pollutants can damage the environment by contaminating plant and animal life and affecting freshwater and coastal ecosystems. People’s health can also suffer if they eat contaminated fish, shellfish, and other aquatic animals, or aquatic plants such as watercress and edible seaweed.
What causes stormwater pollution
Stormwater drains are designed to carry clean rainwater into our waterways. They are not a dumping ground for waste liquids and materials. Pollutants get into our streams and coastal water because people have allowed their wastes, contaminated water and rubbish to enter the stormwater drains. These drains might be right outside your front gate, in your own back yard or on your farm.
Many everyday activities can pollute stormwater systems if you don’t keep wastewater away from stormwater drains:
- washing cars
- washing out paint brushes
- letting cattle wander through drains
- unsafe storage or disposal of chemicals, for example, leaking containers or washing spilt chemicals down the drain.
Find out more about fencing farm drains and check out our information on safe disposal of hazardous substances.
Effects of stormwater pollution
Stormwater pollution may affect your health when:
- Drinking water from streams that have polluted stormwater going into them.
- Eating contaminated shellfish, eels, koura, watercress and fish.
- Bacteria and toxins enter your body through water activities, such as swimming, especially just after rain.
Stormwater pollution affects the environment when:
- Toxic substances, such as vehicle wastes, pesticides and paint, poison streams and waterways. Poisoned waterways are unsafe for swimming and drinking and affect aquatic life.
- Plant material, sewage, and some chemicals starve water of oxygen, choking aquatic and marine life.
- Large amounts of unsightly litter from stormwater ends up in waterways and on our beaches.
- Heavy metals from stormwater accumulate in the tissue of fish and seafood and cause poisoning.
- Bacteria and viruses from untreated human and animal wastes are allowed to drain into natural waterways, making them unsafe for swimming and drinking.
- Sediments from waterblasting, concreting, and earthworking operations affect water clarity.
Find out how to dispose of hazardous substances safely.
Find out about the spiritual connection Maori have with the Waikato River and how the degradation of water diminishes its 'mauri' or 'life force'.
What we are doing
- Environment Waikato regularly monitors the health of coastal marine areas in our Region to assist with policy making and resource consent decisions.
- Environment Waikato manages and monitors resource consents for activities that impact on our coastal marine areas.
- We promote catchment management activities that protect estuarine and coastal ecosystems. This includes Environment Waikato’s Clean Streams Project. We provide information including practical land management guidelines.
- We support voluntary guidelines and codes of practice such as the New Zealand Fertiliser Manufacturers’ Research Association’s fertiliser Code of Practice – aimed at minimising fertiliser runoff.
- We prohibit stock from accessing coastal marine areas.
- We support Care groups. Their riparian management work, such as planting and fencing helps decrease sediment and nutrient runoff to estuaries and the coast via streams and rivers.
- We support ‘Coasts and Us’ school programmes throughout the Region.
Find out more about the provisions in our Regional Plan, Regional Coastal Plan and section 3.5 of our Regional Policy Statement to protect our coastal marine areas.
What you can do
Only clean rainwater should enter our stormwater drains. Don’t be afraid to ask for advice if you’re not sure about what you should be doing to stop pollution getting into them.
Around the home
- Make sure that any contaminated water from your property doesn’t enter the stormwater drains.
- Wash your car and boat on the lawn so that the soapy water and dirt doesn’t enter the stormwater drains, and wash your water-based paintbrush at an inside sink or on the lawn or garden.
- Clean up any spills or dirt around the home by soaking up the mess or sweeping it. Don’t just wash it down the stormwater drain.
- Don’t hose housewashing, concrete cleaning or any other chemicals down the stormwater drain.
Around the farm
- Install proper holding ponds for farm animal wastes.
- Fence off streams from cattle.
Other suggestions
- Store your chemicals in a safe place.
- Don’t tip unwanted paint, oil or any other substance down the stormwater drain. Dispose of them responsibly. See our hazardous substances disposal guide.
Remember, stormwater and wastewater systems are quite different:
- Stormwater - goes directly into waterways.
- Wastewater - is treated before it reaches waterways.
Useful links