Some of Otago's smaller communities are among those which have had bacterial contamination of their drinking water supplies, a Ministry of Health report shows.
The 2012-13 report shows microbiological and chemical quality of water in populations of more than 100 people.
Compliance with all drinking-water standards increased by 0.2% to 77% in population terms during 2012 to 2013, bacterial compliance was 96.7% and chemical compliance was 95.3%, even in small drinking-water supplies which generally experienced greater difficulty in achieving compliance, the report said.
Green Party water spokeswoman Eugenie Sage said most water supply schemes (46%) which had issues with faecal contamination water were in Canterbury, while 11% were in the Bay of Plenty and another 11% in Otago.
''New Zealanders have a right to clean, safe drinking water. People shouldn't have to drink water contaminated with faeces,'' she said.
The presence of E.coli in water indicated it had been contaminated with faeces.
Services affected in Otago were Arrowtown, Cardrona township and Wanaka airport, Kaka Point, Richardson Rural North and Tuapeka West and East.
A Queenstown Lakes District Council spokeswoman said the Arrowtown water supply was not treated, but was tested regularly, and if E.coli was detected, the council applied chlorine.
''An ultra-violet treatment unit will be installed this year, which will disinfect the water.''
The water at Wanaka airport was supplied from a bore and the 2012 problem was due to contamination in a privately owned water tank, for which the owner was responsible.
The Cardrona supply was community run. In 2012, 66 people fell ill with norovirus linked to the township's water supplies.
Investigations were under way to improve its drinking water supply.
Clutha District Council assets manager Jules Witt said the incidents were in small, rural-fed supplies.
