Kiwis are being encouraged to become citizen scientists to check the health of their own lakes, rivers and streams.
Fresh waterways are monitored at hundreds of sites by Niwa and regional council staff, but a study is looking at whether this checking can be widened with the help of community groups, landowners and others.
"If you think of streams and rivers as blood vessels in the body, our regional councils have only enough resources to take samples at a few key arteries - and we are quite keen to get community groups monitoring the veins and capillaries as well," said study leader Dr Richard Storey, of Niwa's freshwater ecology group.
Hundreds of environmental groups were working to restore waterways, and getting them involved in monitoring could result in a far more detailed picture of the state of lakes, rivers and streams, he said.
Volunteers would be given kits for checking indicators including bacteria, nutrients, oxygen, invertebrates, temperature and clarity.