As tourists descend on the Waikato and Coromandel regions over the summer period, the agencies tasked with keeping an eye on assessing the suitability of water for swimming and other recreational activities say water quality is high and most Coromandel beaches are safe for swimming.

The beaches are monitored weekly from November to March by the Waikato Regional Council (WRC) as part of their summer monitoring programme, and most coastal beaches including holiday hotspots Whangamatā, Buffalo Beach, Hot Water Beach and Pāuanui North are open for water activities.

The last samples taken for the Coromandel region’s beaches were between December 18 and 19, and full results can be viewed here.

Samples collected on February 7 2023 show Grahams Stream and the receiving area of Tairua Harbour are generally unsafe to swim.

The site’s catchment contains a mixture of native bush and wetland frequented by many birds and is deemed unsafe due to their contamination. Water quality is not being monitored at this site this summer.

In freshwater environments, fecal indicator bacteria E. coli are introduced via wildlife contaminants which are introduced to the environment through animal and avian excrement, effluent discharges and stormwater run-off.

A Waikato Regional Council environmental monitoring officer collecting samples from one of the sites monitored for contaminants and toxic algae.

Faecal contamination from the bacteria E. coli can cause infections of the ears, eyes, nasal cavity, skin, and upper respiratory tract and gastroenteritis.

In coastal waters, high concentrations of enterococci that come from the gut of warm-blooded animals (including humans) can lead to closure.

On their website, Land Air Water Aotearoa (LAWA) says low counts of E. coli are acceptable in water used for swimming, but when E. coli levels are detected above 540 per 100 mL swimming is not recommended.

LAWA works with the WRC and the Waikato District Health Board to identify any results that may have public health implications and then provide the public with the best quality information; samples are compared with national standard trigger levels to interpret the potential for contamination.

Waikato Regional Council also advises against swimming in murky water or after recent rain.

While the Coromandel has received a clean bill of health, further north in Auckland a swath of the city’s most popular beaches were classed as unsafe to swim on Boxing Day because of faecal contamination.

Water quality website Safeswim red-flagged 27 beaches on the Waitematā Harbour including Narrow Neck, Okahu and Mission Bays and most East Coast beaches from Castor Bay to Red Beach on the Whangaparāoa Peninsula. Nine inner harbour beaches have been black-flagged.