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Land and water pollution

Sources of water pollution

What is water pollution?

Water pollution is when a substance, which is not naturally found in harmful quantities in the environment, enters a natural body of water, including streams, lakes, beaches and groundwater.

How does water pollution occur?

When a polluting substance leaks, spills, is poured, or is washed onto the ground, it usually flows into a stormwater drain. These drains carry the untreated pollutant to the nearest stream, lake or harbour, spreading the pollution to the wider aquatic environment.

Sometimes the substance soaks into the ground, contaminating the land which may pollute underground water reservoirs called ‘aquifers'. These aquifers are used for drinking water, or for manufacturing and farming activities. Near surface aquifers usually contribute to adjacent streams and lakes.

Everyday, many avoidable ‘releases' of pollutants occur throughout the region, due to inattention, accidents, malice and lack of knowledge.

Click on the image below to view an illustration of how pollution can occur, and ways it can be avoided:

Common causes of water pollution in the region

Many substances have the potential to pollute our water. Within the Auckland region, the top five water pollutants are currently:

  • Wastewater - sewer overflow
  • Dirt / inert minerals / sediment
  • Paint / dye / inks
  • Hydrocarbon - oil
  • Concrete wastewater

The message is simple - keep the drain for rain!

If you see water pollution occurring in or near a stormwater drain, stream, at the beach or harbour call our 24-hour Pollution Hotline 09 377 3107.

Like to help? Check out our volunteer page, and join a group near you.

Continue to How to prevent pollution