Storm Francis has battered large parts of the country with high winds and heavy rain.
Elderly residents had to be rescued from the south Down coastal resort town of Newcastle after a river burst its banks.
In Draperstown Co Derry, rescuers had to save nine people from inside a house, along with four outside who were trying to help.
A fire service statement said: “Between midnight and 5pm today we received 49 flooding-related calls and attended 28 flooding incidents across the Newcastle, Maghera, Draperstown and Cookstown areas.
“Working in challenging conditions, firefighters, with the support of other agencies, rescued 37 people from flood water.”
In Co Tyrone the emergency services carried out water rescues.
The Northern Ireland Fire and Rescue Service (NIFRS) added: “With more rainfall expected late into this evening, we have redeployed resources to deal with any further flooding whilst maintaining our normal emergency response.”
Disaster zone
A boat was used to help residents in Newcastle, a picturesque east coast town on the edge of the Mourne Mountains.
Nationalist SDLP Stormont representative Mr McGrath said up to 300 homes in the town had been affected and some streets were under three or four feet of water.
“It is like a disaster zone,” he said.
Those living in the Shimna Road area have been battling flood water since the river the road is named after overflowed.
Geoff Simmons, from south Down, took his children to creche on Tuesday morning and had to take a 20-mile detour over the mountains in wild conditions to get home following “serious” overnight rain.
He said: “The sea looks angry.”
Dundrum Cricket Club ground near Newcastle was completely submerged, with chairman of selection Jeff Maguire saying it had been a decade since they had seen anything like it with water entering the ground from surrounding fields.
“It is frustrating for the ground staff,” he said.
“We have got three elderly ground staff who have worked on it for over 50 years, remarkable stalwarts, and it is frustrating for them because the improvements to the ground have been fantastic.”
A warning for heavy rain and wind remains in place for Tuesday until 6am on Wednesday and it is possible this could lead to debris on the road, fallen trees and spray or large waves on coastal routes.
