Many customers, including thousands of homes and businesses who were left without running water, were "badly let down" by their water company when the Beast from the East hit the UK, according to the water regulator Ofwat.
Its review of how water companies dealt with the Polar blast which hit the UK in February and March found that over 200,000 customers in England and Wales were left without water for more than four hours and over 60,000 customers did not have a water supply for more than 12 hours.
Some people were without water for a week.
Ofwat has now given four water companies, Thames Water, Severn Trent, Southern Water and South East Water, three months to provide a detailed, externally audited, action plan setting out how they are tackling the concerns raised.
It has vowed to take further action against any water company which does not show it will be ready to perform well in the future.
Ofwat's review, called Out In The Cold, states that "in many circumstances customers were badly let down" and there was a "varied" level of performance across the 17 water companies in England and Wales.
Ofwat chief executive Rachel Fletcher says in the report: "We have heard stories of real disruption to people's lives: radio silence on what was happening, businesses shut down and customers forced to make long journeys to pick up bottled water.
"Many customers were effectively left to fend for themselves with local bodies and volunteers having to fill the gap. The situation would have been much worse if not for their efforts."
The regulator wants improvements in emergency planning, preparation, response, communication and payment of compensation for the companies whose customers were badly affected.
The demand is backed by the Consumer Council for Water (CC Water) watchdog which has accused some water companies of making life needlessly more difficult for users by its lack of emergency water supplies and poor communication.
Ms Fletcher warns in the report: "We expect to see concrete improvement plans from companies, particularly those that had the most customers left without supply.
"If we are not satisfied we will take further action so that customers can be reassured that future supply problems will be minimised and when things go wrong their company will look after them properly."
The Beast from the East brought temperatures which failed to rise above freezing in some regions along with huge dumps of powdery snow, freezing rain and strong winds.
A fast change in temperature led to burst pipes and tens of thousands had their water supply cut off for days, according to Ofwat who said a company's performance was not directly linked to the severity of the weather.
It noted that a freeze and thaw in 2010-2011 was more severe for many companies but that impact on customers in this year's blast "depended to a large extent on factors within the companies' control", such as the quality of their plans for handling major incidents.
Severn Trent Water and Thames Water did not have appropriate plans in place while Northumbrian Water, United Utilities, Wessex Water and Yorkshire Water were named among the better performing companies.
They used real time information and monitoring systems to help identify and manage problems.
Ofwat said that poor co-ordination between some companies meant that finding alternative supplies for customers, particularly bottled water, was hampered.
Multiple companies put calls in to the same suppliers at the same time, and they then struggled to meet the large and sudden increase in demand.
Research by the CC Water in seven of the worst affected areas found that 40% of affected customers received no communication from their water company during the incident.
People could not get through to call centres and there was an "overreliance" on digital channels such as Twitter to give up much-needed updates.
Companies have paid out a total of £7 million to customers in compensation.
Payouts from South East Water and Thames Water have been done both quickly and above statutory minimum payments in light of the amount of disruption caused but there has been large variations in payments from the different companies.
Ms Fletcher said: "A number of water companies showed what can be done to serve customers in the face of bad weather.
"But too many companies were caught off guard and let people down, causing real hardship as a result.
"Our report shows there is no excuse for this level of failure."
CC Water chief executive Tony Smith said: "The most affected consumers felt badly let down by their water company, with little or no information and in many cases insufficient alternative supplies of water even for the most vulnerable households.
"As well as good compensation, consumers will want to see companies heavily penalised if they don't act now to put these failures right."
Offering to work with the industry on the report's recommendations, Water UK chief executive Michael Roberts said that in "some areas significant numbers of customers experienced disruption and hardship and we are determined to prevent this happening again in future".