High pH levels have been identified as the issue affecting water in eastern areas of the Western Bay of plenty District today.

Early testing suggests that the water supplied to Pukehina Beach, Paengaroa, Maketu, Little Waihi and Pongakawa areas this morning had high pH, making the water too alkaline, says community relations manager Frank Begley.

Neutral pH is 7 and today's testing found water in the affected areas may have had a pH of 9-10.

'This could be an issue for people with sensitive skin causing irritation and the water should not be drunk, but it is not thought to be unsafe,” says Frank.

'When something like this happens at the water treatment plant the system should automatically shut down until it has been corrected, but this did not occur overnight and Council is investigating what caused this failure.”

The council was advised of a potential issue with the water supply at about 7.30am.

Council staff are now manually operating the water treatment plant at Pongakawa and the Maketu Reservoir has temporarily been isolated.

Parts of the water supply area are being flushed to restore the correct pH balance and this may take a few hours to achieve.

'Residents in the potentially affected areas are advised to not drink or bathe in the water until the all-clear is given,” says Frank.

'Once this occurs people should flush their own systems by running water taps for ten minutes to clear.

'Water cylinders should be flushed completely and households with header tanks are advised to do the same.”

Council Utilities Manager Kelvin Hill says once this has been done people should rub their fingers together in the running water and if it feels slimy to the touch, then keep flushing.

The issue is similar to having an imbalance in your spa or swimming pool water, he says.

'At this stage we believe the effects of taking a shower in this water for people with sensitive skin would be no more than potential irritation and possibly a rash, but we'd advise anyone with concerns to seek medical advice,” says Kelvin.

The council will continue to provide updates on the flushing process throughout the day and advise when the system has been restored. Local schools and the Medical Officer of Health have been notified.

Water is being made available from water tankers and bottled water in the potentially affected areas.