A Ministry of Health report on drinking water shows thousands of people have been drinking water that contains unacceptable levels of E.coli.
The annual report spans the period June 2009 to July 2010.
The report finds that 72,000 people were supplied water from registered supplies that contained unacceptable levels of E.coli.
About 21,000 received water from suppliers that failed to take appropriate action once the contamination was discovered.
Most E.coli strains are harmless, but some can cause food poisoning.
The Green Party says the Government needs to be investing more money in helping communities supply clean, safe drinking water, not less.
It says it hopes the report spurs the Government into reversing its decision to cut the Capital Assistance Programme, which it says has left many communities drinking water contaminated by faeces.