Parts of Newcastle and Newry have been declared an emergency, and Councillor Clarke – who has been out in affected areas since the rain began at 8am – has said the situation is “absolutely horrendous”.
The most affected areas include the Tullybrannigan area, Burrendale Road and the Mourneview estate.
Councillor Patrick Clarke said: “It would appear no lessons have been learnt from what happened in Belfast last week. Representatives on the ground from the water and roads service are working hard to resolve the situation, but people have found difficulties in using the flood line to report problems which is absolutely unacceptable.
“Down District Council has now declared the situation an emergency and have placed other towns on high alert. I am liaising with all the necessary bodies to get answers for those who have been affected and prevent further damage in the area.
“The Northern Ireland infrastructure simply cannot cope with the rain that fell this morning. The majority of manhole covers were either blocked or not working correctly. On several occasions I had to help constituents remove the manhole covers and attempt to clear the drains themselves, in a bid to try and save homes from suffering complete devastation.
“The situation is completely unacceptable. The Regional Development Minister needs to make some smart decisions and invest heavily in updating and maintaining the infrastructure across Northern Ireland. People’s lives should not be left in such devastation simply due to a heavy rainfall.”