No drinking water supplies in Buller or Grey and only two in Westland meet national drinking water standards.
Compliance of water supplies on the West Coast was significantly below the national average, except for bacteriological compliance in Grey, according to the Ministry of Health's 2012-13 report on drinking water quality.
The only fully compliant Coast supplies were Hari Hari and Ross.
West Coast District Health Board chief executive David Meates said several Coast water supplies had been upgraded, including treatment to meet protozoal compliance. However, it was concerning they still didn't meet the protozoal standards.
"In most cases, these have received Ministry of Health Capital Assistance Programme funding to do so.
