More than 50million litres of water have been pumped off of the A14 near Newmarket since it became flooded with rainwater in February, it has emerged.
The road was initially closed on February 22 after it became flooded with rain water between junction 37 and junction 39 in west Suffolk.
One lane remains closed on the eastbound carriage as work is underway to remove the water from the road.
National Highways says the next step is to remove the remaining temporary pumps.
It hopes to have the whole carriageway open "within days".
Martin Fellows, National Highways' regional director, said: "We've removed somewhere in the region of 50million litres of water in the last two months. Which is the equivalent of around 20 Olympic swimming pools.
"Around two hundred metres of the carriageway has suffered. This section is in a dip, so with the heavy rainfall we've had 'the perfect storm'.
"We understand the public's frustration and ask that they remain tolerant. We'd also ask that people respect the temporary speed limit whilst work continues.
"In the longer term, we'll be looking at ways of ensuring this cannot happen again."
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