Two ministers have written to people living in Grands Vaux with an update on plans to prevent future flooding.
More than 50 households were evacuated and a major incident was declared last month when the nearby reservoir overtopped after half a month's rain fell overnight.
Infrastructure's Deputy Tom Binet and Assistant Environment Minister Deputy Hilary Jeune have replied to a letter from worried residents.
They say they are working on immediate actions to protect homes and long term plans to improve water management in the catchment.
Deputy Jeune, who has political responsibility for mitigating the effects of climate change, says the ground was saturated following weeks of heavier-than-average rainfall.
That meant water discharged more quickly than it normally would have, overwhelming the Victorian sewage system.
The reservoir overspilled, sending more water into the inundated drainage network.
Deputy Jeune says, though the drainage system has been adapted over the years, 'essentially, capacity in this location is the same as it was at the time of its first installation.'
"From initial investigations, I’m told the majority of drains and drain inlets were clean at the time of the downpour. There is no way that the current drainage system could ever have coped with the volume of rain that fell, nor could the existing system be adapted for this purpose."
Deputy Jeune says the reservoir 'did exactly what it was designed to do, and its structure 'remains completely robust'.
"Since the floods, officers from our Infrastructure, Housing and Environment department, alongside Jersey Water, have been carrying out extensive investigations around Grands Vaux and surrounding areas.
They are doing a full assessment of the drainage network, impounding areas and the reservoir itself, to work through exactly what happened, and the potential solutions available to us to mitigate such an event if it were to happen again."
Jersey Met is working on developing a better warning message service as part of flood management plans.
Deputy Jeune's letter concludes:
"Whilst every effort will be made to stop such flooding happening again, a failsafe short-term solution may be very difficult to achieve. We are completely committed to keeping you up to date and informed about our progress."
Infrastructure Minister Deputy Tom Binet and Assistant Environment Minister Deputy Hilary Jeune have written to Grands Vaux residents.
In his separate letter to residents from Infrastructure Minister Tom BInet, he says some areas of the drainage system were not 'clean and clear' and had 'not been maintained for some time', but add that would not have prevented the flooding in these circumstances:
"This is simply because, however clean the system may be, it could never cope with the volume of water that fell during the main downpour, particularly if the reservoir was full from the outset. It would require a vast underground drainage pipe, running under St Helier, from the reservoir, out to sea.
Rough estimates indicate a figure in excess of £200m for that to be achieved."
He says an integrated plan and extended remit is required and work undertaken so far will be presented at meeting between his IHE department, Jersey Water, Andium Homes, the Environment Minister, Treasury Minister and representatives of the three parishes involved -St Saviour, Trinity and St Helier.
"Whist there are no guarantees, the hope is that we can, collectively, devise a plan and series of measures that will both reduce the risk of further flooding and mitigate the effects in the event that it cannot be fully avoided."
A meeting with residents will be organised for mid to late- March to give a further update.