Havant MP David Willetts has demanded action after it was reaveled that a drain which overflowed and caused massive flooding in Emsworth was more than three times over its capacity.
Mr Willetts said the drainage channel that overflowed to flood surrounding streets was totally overwhelmed by the rainfall on November 9 last year.
Now he is demanding the capacity of the culvert is increased and more drainage channels are built in the town.
It comes as residents, many who have been unable to return to their damaged homes, are demanding an early warning system on the West Brook.
But the Environment Agency does not want to install sensors - which would let residents know by a phone call or text - as it says it could lead to too many false alarms.
The concerns were revealed as Mr Willetts met officers from the agency in the worst-affected area of Bridge Road.
Mr Willetts said: 'The water going through the stream was at seven or eight cubic metres per second and the capacity of the culvert is less than two cubic metres per second.
'The run-off of water at times of heavy rainfall is much greater than the culvert can handle.'
Mr Willetts believes the problem has been exacerbated by more development in the Emsworth area, as well as the building of the A27 embankment.
The Environment Agency has acknowledged that the embankment may be blocking some of the rainfall run-off.
Maggi Bunce, 58, who has moved out of her house in Bridge Road, along with many other residents, said residents wanted to be prepared if another flood came.
She said: 'I would certainly rather have the odd false alarm.
'With today's technology, there must be some way of getting an early warning system. There could be false alarms, but people would prefer that to getting flooded.'
The Environment Agency has commissioned consultants to work out the exact cause of the flooding.
Despite initial fears that the culvert was blocked with leaves, the agency has said it was cleared the day before the flood as part of a twice-weekly cleaning schedule.
Officers say more than one month's rainfall fell in the hours before the flood.
Mike O'Neill, area incident manager at the agency, told The News it was looking into increasing the size of the culvert and creating more drainage channels.
He said: 'We also want a solution as quickly as possible. We are meeting with residents again next month.'
Regarding the early warning system, he said: 'It is technically possible.
'But, because the West Brook is so flashy, it's so quick from the rain falling to the stream rising, an accurate warning system is not possible.'
The agency is looking into residents volunteering to become flood wardens to monitor water levels.