A state of emergency, declared on Friday night by Mayor Gary Kircher after heavy rain battered North Otago, would not be lifted until sometime on Sunday.
A MetService spokesman said in the 24 hours, form 9am on Friday to 9am on Saturday 134mm of rain fell in Oamaru. In the last 60 hours, rainfall record figures show a reading of 169mm.
Earlier on Saturday, it became evident that sewage may have contaminated a number of properties in Oamaru's north end.
When the area experienced big rain events a lot of storm water systems flooded into sewerage systems.
"We've ended up with storm water in the sewerage systems, particularly up in the north end, Mr Kircher said.
There had been a "considerable inundation of water into the sewerage system that has caused sewage to escape."
The number of properties affected was not yet known.
"Our reticulation guys are out and about and we'll have a much better idea soon. They're doing ongoing assessments."
Mr Kircher said if people thought they were in an area where they could smell sewage, or thought they were in an area that could be contaminated, they needed to make sure they stayed clean and hygienic to reduce their chance of getting sick.
People had been advised to keep their toilet flushing to a minimum, Mr Kircher said, but hoped that level of care would be dropped later on Saturday night as flood waters receded.
"The drains won't be taking in the same amount of water they were. We should be able to resume normal transmission, so to speak."
Mr Kircher said the district's state of emergency had been surpassed by the regional state of emergency.
"I'm very comfortable with that. It overruns the district. We were looking into the implications of over lifting our own one and we thought about the regional one. It just gives us further ability to sort out any practical issues that come along."
Slips threatening houses as well as blocking roads and the railway line at Shag Point were now a major concern.
Mr Kircher said the Waitaki Emergency Operation Centre was still operating and so if people had issues or concerns they could contact staff manning the phones to seek assistance when needed.
"In any emergency situation call 111."
Mr Kircher expected the state of emergency to stay in place until Sunday afternoon.
Couple rescued
Police had to wade arm and arm to rescue a couple and two would-be saviours from flood waters on Friday night in Oamaru's north end.
Sergeant Tony Woodbridge, of Oamaru, said two people had gone to a Caen St, Oamaru, address to rescue a older couple, but had become stuck when the flood waters surrounding the home became too dangerous to cross.
Conditions were so bad water was seeping into the house, he said.
Normally the house has a tiny creek which runs along side it, but last night it had grown into "raging torrent".
Police were called and had to link arms to reach the trapped people and their dogs, Sgt Woodbridge said.
Mayor Gary Kircher said part of Saturday's recovery effort included search and rescue teams going out to flood-ravaged areas to check on isolated communities and families.
Senior Constable Nayland Smith arrived from Omarama with a search and rescue team who were heading to the Corriedale area, Mr Kircher said with emergency groceries "just in case."
A helicopter was on standby at Oamaru Hospital to help with transport if needed.
Coastal areas hit
The main damage from the rain recorded had been in the coastal areas, Mr Kircher said.
"Talking to [someone] in Omarama there doesn't seem to be too many issues up there. It's one of those situations there's a lot of communities impacted, but it hasn't been quite across the district."
Infrastructure had held up in parts.
"In places it's gone really well, in others we're never going to have the infrastructure to deal with the water we've had.
"We expect further through the assessment we'll be able to see the level of extent of the damage. We're expecting to see a lot of road repairs required."
State Highway 1 from Waikouaiti to Oamaru reopened at 2pm on Saturday. Motorists were warned to travel with care as there was still flooding in some parts of the road.
Meanwhile, Oamaru's Humber St bridge has been closed and may stay that way for up to a month after a hole opened up in its northbound lane on Saturday.
Water worked its way behind the bridge's abutment which had undermined the road above.
Volunteers kept Waitaki working overnight, says Civil Defence.
Waitaki Civil Defence spokeman Elton Crane said volunteers such as the fire brigades and power company Network Waitkai crews were kept busy all night attending calls.
"There's been a huge volunteer effort."
Road crews were now out in the district checking the conditions of roads and would report back in about an hour with results of what flood waters had caused, he said.
"The main focus is recovery. We believe the water is beginning to subside. All of the large puddles are going now, but we realise that's not the case everywhere."
Mr Crane urged people to now check on their neighbours to make sure they were okay.
