Update: After extensive flushing pH levels are returning to normal in the Western Bay's water supply.
Residents were still advised to run their taps for ten minutes before drinking or bathing any water in Pukehina Beach, Paengaroa, Maketu, Little Waihi and Pongakawa.
To test the water, rub your fingers together in the running water and if it feels slimy continue flushing.
Western Bay of Plenty District Council has apologised to people affected by today's water issues.
People could also experience low water pressure through to mid-evening due to the system-wide flushing.
Investigations were continuing into why the warning system at the water treatment plant in Pongakawa failed over night. It was being managed manually in the meantime.
Earlier: The all clear has been given for Pukehina Beach water supply, though residents have been warned to flush their systems before drinking or bathing.
People should still not drink or bathe in water in Paengaroa, Maketu, Little Waihi and Pongakawa. The all clear for these areas was not expected to be given until later today.
Council water supply technicians have completed flushing Pukehina Beach's water supply system which showed a high level of pH this morning.
Pukehina residents should still run water taps for ten minutes to ensure the fresh water supply was coming through the system.
Western Bay of Plenty District Council utilities manager Kelvin Hill said once this was done, residents should rub their fingers together in the running water and if it felt slimy to the touch to keep flushing.
Water cylinders should be flushed completely and households with header tanks were advised to do the same.
Council would be using signage to inform residents of the need to flush their water systems but has asked residents to spread the word and inform neighbours and friends - especially those coming to the beach from out of town.
Mr Hill said this was a timely reminder for people to keep an emergency supply of fresh drinking water as part of their household emergency plan.