It follows a recent study showing between 300,000 and 800,000 New Zealanders were exposed to potentially dangerous amounts of the chemical, which may contribute to bowel cancer.
Canterbury's town drinking water supply had the highest nitrate levels in the country.
Reports showed 3215 people drank water with levels so high health authorities required regular testing to ensure it did not slip above the recommended safe threshold.
The testing, being offered next month in Leeston and Darfield, was the idea of the local water zone committee, a group that acted as a link between the community and Environment Canterbury, and advised it on policy.
Its co-chair, Fiona McDonald, said the main risks were to pregnant mothers and bottle-fed babies as well as a potential link between even quite low levels of nitrate and bowel cancer.
"Those are the two things, particularly the media attention that the colon cancer research has had lately, that's really raised the level of attention on nitrate levels, and we're hoping to have really good engagement and really good turnout in these rural communities."
The tests were being offered to those using private bores.
Unlike town supply drinking water, which was regularly tested by councils for things like nitrate levels, these bores - serving 451,403 people nationally - were the responsibility of homeowners to get tested.
It was also thought the water in these mostly shallow bores presented more of a risk, with estimates 19,960 could have nitrate levels exceeding World Health Organisation limits.
McDonald said the tests would be indicative only and it would then be up to homeowners to get their water tested at a laboratory.
"It concerns us, individual well owners don't necessarily have good knowledge about their own water supplies. The council has really good knowledge about the water supplies it provides, but it's those individual owners [where] it can really vary."
The testing followed an informal effort by a group of concerned residents to let private well users know about the state of their water.
Last August, Springston South homeowner Mike Glover got together with the Federation of Freshwater Anglers, who had managed to get hold of specialised equipment needed to test nitrate levels.
They invited people along to have their water tested, for a gold coin donation.
Eighty turned up including one woman who was shocked to discover the water from her spring was potentially dangerous to drink.
"She was in tears. She said 'I tell everyone about the water, it tastes so good', and I said that's the bloody thing, nitrate, you can't taste it, you can't smell it, you can't see it. You know if it made the water go red, all the rivers in Canterbury would be running pink."
Glover was glad the water zone committee was now picking up the baton.
"It's the start of something perhaps. I think they may be surprised at the level of not just interest, I think there'll be a lot of concern shown and possibly a little bit of anger."
Federation of Freshwater Anglers president and Canterbury resident Peter Trolove said the problem was a case of the region's chickens coming home to roost after two decades of unfettered growth in dairying.
"People are suddenly saying 'I don't want to live here'. And so they're looking to sell up," Trolove said.
"The Selwyn region's the fastest growing area in New Zealand. Well, we might have people departing at the same rate when they realise that they might be drinking water that's not good for them."
McDonald said further testing may be done, depending on the level of demand this time around.
