Northland drinking water nitrates targeted at upcoming Fieldays

13 Feb, 2023

Northland bores and springs bode well in current nitrate water testing by groundwater scientists at GNS Science.

For the next year GNS Science, under a community research program, NitrateWatch, will offer a free nitrate testing service for rural Northland residents to mail in potable water samples from their springs and bores. Town-supplied water is routinely tested by district councils to ensure that the source is safe for the population to drink, but who tests rural areas that rely on bores and springs for their drinking water?

“Our goal is to support rural Northland communities look after their drinking water by offering a free, confidential testing service to measure nitrate levels in drinking water,” says GNS senior scientist, Karyne Rogers. She says the drinking water results have been promising and better than expected. The New Zealand drinking water standard allows up to 11.3 milligrams of nitrate for each litre of water.

“So far, our testing shows that the nitrate levels from around 60 samples submitted by local residents have been significantly under the limit and often below one milligram per litre.”

Nitrate contamination of drinking water can happen when dairy and farming waste, fertilisers or septic tanks leach through the soil and mix with the freshwater stored underground that is extracted as drinking water. There is no simple way to remove nitrates from drinking water. Boiling water removes harmful bacteria that could cause stomach upsets, but it does not remove the nitrates.

The team of scientists are looking at trends across the region, rather than by specific bores, to check if there is an excess of nitrate in drinking water from some areas of Northland.

“We will be able to look at different regions to determine if some areas have slightly more elevated nitrates than others. We want to ensure that Northland residents all have access to this testing.

“We encourage people to test their water and have confidence in their nitrate content. The individual nitrate results are kept confidential and returned directly to the submitter. The broader trends will be used to ensure water quality is being maintained in each region.”

n The NitrateWatch Team will be at Northland Field Days 2023, March 2-4 in Dargaville. Bring along a sample of your drinking water in a clean jar and get it tested on the day or pick up a free testing kit. Testing kits can also be requested from nitratewatch@gns.cri.nz.