Water Quality Results Confirmed In Nelson Tasman Waters, Rāhui Lifted

Scoop

02-08-2025

Post-flood sample testing of water quality at 22 sites across the top of the south has returned a blanket set of good results (see table below), enabling the current rāhui to be lifted from 1pm on Saturday August 2, 2025. This also provides confidence for those looking to enter or use the water once again.
Concerns were initially raised around the effect of floodwaters on the coastal and marine environment in the aftermath of the weather events in late June and mid-July.
A rāhui was implemented from Saturday 28 June, covering the area from Te Parinui o Whiti (the White Bluffs) in the east, west to Kahurangi Point, including Aorere and Tai Tapu.
It covered all coastlines, river mouths, and floodwaters, and asked for people to respectfully refrain from the gathering of seafood and kai in these areas as well as swimming and entering the water.
The consistency of results across the entire Tasman and Golden Bay areas has given sufficient confidence that the water quality is back to pre-flood condition and our coastal waters are now safe for swimming.
However, the quality of the water in the immediate vicinity of the Motueka wastewater treatment plant still presents risk to swimmers, gatherers of kaimoana and a separate rāhui will remain in place for this area.
Rāhui are a voluntary measure and non-enforceable, but are another way of trying to keep people safe, especially when considering the impacts on the environment and potential contaminants in the waterways.
As part of ongoing monitoring measures, water samples have been collected by Nelson City and Tasman District Councils at coastal beaches and river mouth sites over the last two weeks.
Sample results from five locations in Golden Bay, 11 locations across the Tasman Bay coastline and six locations with the NCC-administered side of Tasman Bay showed particularly low levels of Enterococci and E.coli.
The national guidelines for safe limits in New Zealand are 280 enterococci/100ml for our coastal sites and 540 E.coli/100ml for our river sites.
Without exception, all sites returned results well under these limits in multiple tests, with only five sites showing more than 10 parts per 100ml at any stage. The maximum reading was 74 Enterococci / 100ml, recorded at Riwaka Port on July 25.
The effects of heavy rainfall on July 29 only caused a very short-term increase to these concentrations. Our data from the last few decades shows that the water returns to a swimmable quality within 48 hours of a rainfall event.
In this case the water would be deemed safe for re-entry by Friday 1 August 2025. However, there may still be risks for shellfish gathering for another fortnight.