Horizons Regional Council want people to check wellheads are secure

Horizons Regional Council is urging people to check their wellheads are secure. Photo / Supplied

Horizons Regional Council is urging people to check their wellheads are secure to prevent the contamination of harmful substances.

“People who consume untreated water from a contaminated well could become very ill,” Horizons groundwater scientist Stephen Collins said.

“So, it’s important Horizons works with owners to ensure they are aware of the risks and how to mitigate them.”

Collins said groundwater in Whanganui was used for municipal drinking water, industry and farming, and the quality was generally good.

”There is still a need for land owners to ensure their bores are secure and properly constructed to prevent potential contamination from the surface making its way down to groundwater.”

Collins said there was room for improvement of groundwater bores across Whanganui and the rest of the Horizons region.

“We generally have good groundwater quality around the region, but we acknowledge there are also hot spots for nitrate and occasionally other contaminants.

“Where we have long-term trends available, these often show improving trends. However, there is definitely room for improvement in the general condition of bores that we see around the region,” Collins said.

National groundwater monitoring results published by the Land, Air, Water Aotearoa (Lawa) project last week showed the Horizons region ranks in the middle of the country in terms of groundwater quality.

“Unsecure wells represent a potential pathway for pathogens such as E. coli to enter groundwater from the surface, posing a risk to surrounding drinking water supplies,” Collins said.

E.coli is a bacteria commonly found in the intestines of humans and other animals, some strains of which can cause severe food poisoning.

According to the Lawa website, nine times the amount of acceptable E.coli was detected in a Whanganui bore on Seafield Road in January 2021, leading to treatment of the bore to make the water drinkable again.

Potential points of entry to groundwater from a well can be from down the sides of the well casing or openings in the wellhead itself.

Contaminants that enter a well can travel through groundwater, and other wells can draw these up.

“To mitigate this risk, landowners can ensure there is a sloping concrete pad around the base of the bore and that the wellhead is completely sealed from the outside,” Collins said.

Horizons has implemented a programme surveying wells and carrying out wellhead security assessments across the region. The assessment included a visual inspection of the well and its current set-up.

If landowners have any questions or concerns about the security of their wellhead, they can email groundwater@horizons.govt.nz or call freephone 0508 800 800, and Horizons will arrange a site visit.