The Clutha District Council was last night scrambling to find a suspected major leak in one of the district's rural water schemes.
If the leak was not found, it could lead to widespread water outages, as supply on the North Bruce rural water scheme was already ''critically low'', said Clutha District Council district assets manager Jules Witt.
Restrictions were placed on about 300 rural properties from Lovells Flat to Waihola yesterday.
''If it's really difficult to find. It might take us two weeks to find it and if that happens, we will be potentially in some trouble to supply everybody in the area,'' Mr Witt said.
''Hopefully, we can turn it around pretty quickly.''
The council operated the third-longest water network in the country, behind Auckland and Christchurch, he said.
The ''massive area'' typically required farmers and residents to alert the council to problems with rural water schemes as they arose.
Leaks had occurred in the North Bruce scheme since early January, but they had been found and fixed, Mr Witt said.
The council had identified an issue and monitored the scheme's reservoir for the past week, Mr Witt said.
''It became clear yesterday (Wednesday) it was pretty serious.''
''Hopefully, with a bit of attention now and a concerted work effort by us and our contractors, we can figure out what's going on and, hopefully, keep things ticking along.''
A similar situation at the Moa Flat rural water scheme in West Otago about 12 years ago resulted in significant restrictions, Mr Witt said.
Lindsay Watt, a sheep farmer at Lovells Flat, said he had not heard about the suspected leak when contacted by the Otago Daily Times .
The ground in South Otago, one of the only places in the east of the South Island that is not suffering from drought, was not particularly dry.
Mr Watt said he had received up to 8mm on Wednesday night.
He had a second, private source for water on site.
''We're looking all right in that department,'' he said.
Water restrictions compounded by drying conditions would have a greater impact on dairy farmers in the area.
''It's critical for them every day,'' he said.
Dairy farmers contacted yesterday did not return calls.
Mr Witt said the North Bruce water scheme was built in the early 1980s and was ''not at all'' considered ageing infrastructure.
The council and contractors were monitoring bulk water meters on main lines and measuring flow to pinpoint problem areas yesterday.
Residents on the scheme were prohibited from ''unnecessary water use'' until further notice.
Farmers were urged to check on-farm supplies for leaks and to turn off any non-critical systems.
The council would issue an update on Monday, Mr Witt said.
