More households are expected to lose running water in south-east England and some could face Christmas Day without it.
Water companies are working to ensure tens of thousands of homes in large parts of Sussex, Kent and Hampshire are reconnected by the weekend.
Firms said the rapid thaw of frozen pipes had increased the number of bursts and leaks on the underground network of pipes, causing storage reservoir levels to drop after temperatures plunged below zero.
Southern Water said on Wednesday evening: "We're sorry that our customers in SO15 - Southampton; SO16 - Bassett, Nursling, Millbrook, Chilworth, Chilworth Village Lord's Hill; SO19 - Bitterne; SO21 - Compton, Compton Down, Hursley, Otterbourne, Shawford, Twyford; SO22 - Badger Farm; SO31 - Bursledon; SO50 - Eastleigh; SO51 - Ampfield, Braishfield; SO52 - North Baddesley; and SO53 Chandlers Ford are without water.
"We are expecting more customers in the wider Yew Hill area - SO15, SO16, SO18, SO19, SO21, SO22, SO30, SO31, SO50, SO51, SO52, SO53 to lose either water pressure or supply in the coming few hours.
"It's likely that this loss of pressure or water supply to your home will continue for at least the next 48 hours."
South East Water said it is "committed to getting its customers who are currently without water back in supply by Christmas Day if not sooner".
The firm said there had been a 300 per cent increase in the number of bursts, and chief executive David Hinton told BBC South East Today about 5,000 properties were still affected on Wednesday.
In Tunbridge Wells, water will remain off until Thursday morning.
A South East Water statement said: "It is impossible to predict which pipes will burst and where, and we're working 24 hours a day to find and repair these bursts and leaks as quickly as possible.
"We have also used tankers to inject more water into the system to keep supplies going for as long as possible.
"We're seeing a lot of demand on the network and ask you to check your lofts, airing cupboards and outside taps for leaks if you're able to."
Emergency supplies of bottled water have been delivered to towns and villages.
Southern Water said in a statement: "Throughout the day, our teams have worked hard to minimise the impact of restricting water to our customers.
"The significant pressure on our network means that demand continues to outstrip supply. We have had to make some difficult decisions to ensure that we protect critical infrastructure across Hampshire such as local hospitals."
The firm said bottled water stations had been opened in Hampshire at the east and south park and rides in Winchester and Places Leisure in Eastleigh.
The statement added: "More bottled water stations will be opening (on Thursday) and we'll confirm locations and times on our social media channels and on our website.
"We are very sorry for the disruption and inconvenience this is causing, particularly in the days before Christmas. We are working as hard as we can resume services by Sunday."
Caroline Nokes, MP for Romsey and Southampton North, tweeted: "I've asked Southern Water to set up a bottled water station in Southampton - not acceptable that the closest one is the park and ride at Winchester.
Have tonight asked @SouthernWater to provide bottled water at a location accessible to Bassett residents https://t.co/SuzffpyTUO
— Caroline Nokes MP (@carolinenokes) December 21, 2022
"Appreciate the network is under extreme pressure, but residents reliant on public transport cannot get to Winchester tonight."
Mr Hinton said in a statement: "Our teams are working flat out to find, fix and repair the leaks on our pipes but we're asking customers to help too by checking their homes, businesses, empty properties, outside taps and troughs in any fields for leaks and get them repaired as soon as possible.
"Leaks within properties can cause extensive damage which can be costly to repair."
