Indicators at a glance - recreational water quality

This section summarises the latest Environmental Health Indicators about recreational water quality and water-borne disease in New Zealand. 

Summary

Contact with recreational water which is contaminated with pathogens (such as bacteria and viruses) can lead to contracting certain waterborne diseases, particularly gastrointestinal illnesses. Animal manure and human sewage are the main sources of pathogens in New Zealand waterways.

Faecal matter from livestock can contaminate waterways through: (1) surface run-off of faecal matter into waterways, (2) livestock defecating directly into waterways, and (3) leaching into groundwater.  

Indicator Key findings
Suitability for Swimming
  • During the 2018–19 bathing season, 75.0% of monitored river swimming sites, 40.6% of monitored beach sites and 24.1% of monitored lake sites were unsafe to swim at on at least one occasion.

  • In the 2018–19 bathing season, 27.5% of monitored river swimming sites, 14.0% of monitored lake sites and 7.8% of monitored beach sites were frequently unsuitable for swimming, with 20% or more of regular water quality samples showing they were unsafe to swim.

  • Based on measurements taken between 2016–19, 51.2% of monitored freshwater bathing sites (rivers and lakes) and 6.8% of bathing sites at beaches were unsuitable for swimming at any time, with an overall high risk of bacterial infection.

  • The Manawatū-Whanganui had the highest proportion of unsafe freshwater swimming sites - 90% of all monitored sites in the region were unsuitable for swimming. The Hawke’s Bay region had the highest proportion of unsafe beaches, with 14% of all monitored beaches being unsuitable to swim.

  • Between 2016–19, both freshwater and marine swimming sites in urban areas were least likely to be safe to swim, in contrast to rural areas.

Agricultural activity
  • Total livestock numbers dropped by 25% from 2002 to 2019, mostly due to a decrease in sheep numbers.
  • Dairy cattle are the only livestock type to have become more numerous. Numbers rose by almost a quarter from 2002 to 2019, from 5.2 million in 2002 to 6.3 million in 2019.
  • There was a marked diversification away from specialised sheep farming and into mixed sheep and beef cattle farms.
  • The area of irrigated agricultural land has almost doubled since 2002. Three-quarters of all water used for agriculture is taken from lakes and rivers.
Water-borne diseases related to recreational water
  • The age-standardised campylobacteriosis notification rate was 132 per 100,000 people in 2018 (6,463 notifications). This was approximately the equal lowest rate since reports began in 2001.
  • The age-standardised notification rate for cryptosporidiosis was 38 per 100,000 people in 2018 (1,551 notifications). This was approximately the equal highest with 2001.
  • The age-standardised notification rate for giardiasis was 31 per 100,000 people in 2018 (1,392 notifications). This has remained unchanged since 2015.
  • Notification rates for potentially waterborne diseases continued to be higher for children aged 0–4, people of European/Other, and people living in less deprived or rural areas.
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