Marlborough District Council is reassuring residents over the danger posed by a dam at increased risk of breaking after Friday's earthquake.
It says in a worst-case scenario, eight rural properties, approximately 12 houses and up to 24 sections in Seddon township on the south-eastern side of Starborough Creek could be flooded if the dam was to breach.
However council chief executive Andrew Besley says the dam only has a 3 or 4% chance of breaking and residents would have an hour and a half's warning before the water arrived.
Mr Besley says the flood waters would only be about 10 centimetres high and would not be travelling quickly.
After Friday's earthquakes Marlborough district council decided to lower the dam level as a precautionary measure in the interest of public safety.
Heavy weekend rain has slowed that work.
But while the drainage process was underway, the dam engineer identified more problems with the stability of the dam.
