An engineer has blamed Ewell's flood on a failure to clean out drains and widen water courses.
Flooding has inundated the pavement and part of the road outside Bourne Hall Park at the end of the high street for over a month.
Graeme Hitching, a former technician for a multinational engineering company, said workmen with pumps at the site confirmed that the flooding was because Surrey County Council had not cleaned the road drains.
He said sluice gates were only opened last Friday and the council needs to take action to unblock pipes under the road and suck the sediment out of highway drains.
He said: "Firstly, there are blocked drains in the carriageway, which would alleviate the flooding if they were to be cleaned out.
"Secondly, the body of water by the monument, behind the bus stop is flowing into the lake.
"Therefore, by even the simplest of reasoning, boring a hole between the two would lower the level outside Bourne Hall and hence stop the flooding.
"Thirdly, in the long-term, there needs to be widening of the water course under Kingston Road, adjacent to the old ford and under the mill itself.
"One of the water courses has reduced flow due to vegetation, the other has remnants of the old water management system partially blocking it.
"Doing these simple and cheap improvements may not win votes, but compared to other capital projects, these would actually benefit the community."
A Surrey County Council spokesman said: "The main problem here is that when the levels of water in the pools either side of London Road are as high as they have been for several weeks, the water on the road loses its chief escape route.
"However, we are very aware of the part the highways drainage may play, and before the flooding began we were already investigating it and had made a change to see if this would help clear water on the Bourne Hall side of the road.
"We are working with the borough council to see whether there are any blockages within the Bourne Hall site that are stopping water getting into the Hogsmill River and away and if necessary will also request the Environment Agency's involvement."