Alan Horgan said he found that municipal facilities are generally audited every three years as required, but registered facilities are not. These 1,600 registered water supplies are typically wells used by restaurants, apartments, campgrounds, schools and nursing homes.
"The nature of the inspections and the fact that audits for the registered water supplies were not being done as frequently as required increased the risks," Horgan told a news conference.
Among other things, Horgan found instances when water samples were not obtained from registered facilities within the required 30 days after a boil advisory was removed.
As well, guidance for staff was inadequate, which resulted in a lack of followup after deficiencies were found in previous audits, the report adds.
"The fact that there isn't much guidance out there resulted in inspectors doing their own thing, and thus being inconsistent," Horgan said.
He said the inspectors' managers were unable to provide clear expectations of how audit checklists should be filled out.
"We noted instances in which audits were partially completed, and inconsistencies among inspectors in how audits were conducted and when audit reports were issued," the report says.
The report makes 19 recommendations to fix the problems including a call for an investigation into the department's audit tracking system and development of better guidance for facility audits and water testing.
Environment Minister Randy Delorey said he has accepts Horgan's recommendations. However, he insisted the risks associated with these lax standards were low.
"What we haven't seen is public-health concerns or outbreaks attributed to public water in the province of Nova Scotia," he said.
"I think that's a testament to the fact that the risk level is low."
Conservative critic Chris d'Entremont challenged that view.
"As a father, I want to know that the water that my kids are drinking in school or that my grandparents are drinking in a long-term care facility is quality water," he said.
"I don't think that this government can truly gives us a report on whether they are or aren't. So this is a big competency issue for this government."
The department has 73 inspectors. Nine of then work solely on the public drinking water supply.
Aside from the registered facilities, there are 84 municipal water supplies in the province that provide drinking water to about 60 per cent of the province's residents.
Of the 20 municipal audits Horgan examined, nine were not audited within the three-year deadline. But the delays were typically between three and six months.
Among the audits of registered facilities, 38 were examined and 23 — or 61 per cent — were not completed within the three-year deadline. The report says 13 were between 23 months and 10 years late.