Many parts of the UK were left under water in the summer floods
Thousands of people whose homes were flooded last summer were not warned early enough, a report has said.
The Environment Agency makes 33 recommendations and concludes it responded well to the emergency.
But it adds that 35,000 homes and businesses were not covered by an early warning system and that more money should be spent on urban drainage.
The worst of the floods - estimated to have cost £3bn - hit Yorkshire, Gloucestershire and Worcestershire.
Environment Secretary Hilary Benn said the most important lesson from the report was that more people need to sign up for the official flood warning service.
Currently only 41% of householders in high-risk areas are signed up. The agency suggests if the service was more widely adopted, many more people would have the time needed to flood-proof their properties.
The agency wants the government to register more people for the flood warning service by allowing the use of ex-directory numbers and the electoral roll.
Those who did not want to be part of the system would then have to opt out of it.
Speaking to the BBC, Mr Benn said the government had already pledged extra money to spend on better flood defence schemes.
The agency estimates it will cost £1bn a year to protect people adequately in the coming years.
Environment Agency chairman Sir John Harman said that two-thirds of flooded properties were damaged because drains and sewers were overwhelmed.
He said that there was "complexity" of who is responsible for surface water flooding.
Both the government and the agency are agreed that the Environment Agency needs to take a "strategic overview" in England, and that local government, water companies and the Highways Agency must work better together at a local level.
Sir John said: "We need a clear co-ordinating framework to deal with flood risk from drains and sewers," he said.
The report says companies that run power stations and other utilities must take responsibility for flood-proofing.
Sir John said: "The extreme flooding showed just how poorly protected much of our vital infrastructure is - and water and electricity supplies were particularly vulnerable."
The agency admits that it did not erect temporary flood defences at Upton-upon-Severn and Worcester in time because of severe flooding on the roads.
It says it needs to agree with its partners a policy for deploying these types of defences.
Overall, the report says the agency responded well to the wettest May to July period in 250 years. In total 55,000 homes and businesses were flooded.
"The Environment Agency has come through better equipped to deal with future events and tackle the challenging impacts of climate change," said chief executive Baroness Young.
Mr Benn said although he agreed that the Environment Agency and emergency services had generally coped well with the flood, there were "lessons to be learnt".
In particular new guidance to planning authorities had been issued making it a requirement that they take potential flooding into account when developers apply to build new houses.
He said: "Adequate protection against flooding must be put in place, but if it cannot, then planning authorities must think very carefully whether they grant permission to build."
The Environment Agency report will form part of an independent review of "lessons to be learnt" from the summer floods.
The review is being carried out by Sir Michael Pitt and a preliminary report is expected by the end of the year.