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Water quality at coastal swimming spots

New Zealand’s coastal beaches, rivers and lakes are widely used for a range of recreational activities such as swimming, sailing, surfing, water skiing and underwater diving. Maintaining and protecting recreational water quality is therefore an important public health and resource management issue.

Latest coastal water quality compliance with E. coli guidelines is available in the Snapshot of recreational coastal sites.

Regional and district councils in New Zealand monitor water quality for recreation at about 350 coastal sites every summer (and about 200 freshwater sites).

Water samples are typically taken once a week over the summer and tested for the concentration of enterococci bacteria. Enterococci bacteria, while generally not harmful themsleves, indicate the presence of faecal material and disease-causing micro-organisms in coastal waters.

The enterococci results are compared to the ‘action’ threshold of 280 enterococci per 100 millilitres of water from the Microbiological Water Quality Guidelines for Marine and Freshwater Recreational Areas (also known as the 'guidelines for contact recreation').

Did you know?

  • Recreational water quality can be affected by effluent run-off from farmland, human wastewater discharges and stormwater outfalls. Bacteria levels are often highest after rainfall.
  • Seawater that has been contaminated with human or animal effluent can carry a variety of disease-causing organisms.
  • Disease-causing organisms can pose health risks to people using coastal beaches for activities like swimming, sailing and surfing. Very young children, the elderly or people with impaired immune systems are particularly vulnerable.

Information on the limitations of the water quality at coastal swimming spots indicator.

The above information has come from the snapshot report on recreational water quality and Environment New Zealand 2007.

Last updated: 29 July 2010