Thousands of homes and businesses in Northern Ireland are still without water, some since before Christmas.
Northern Ireland Water said it was alternating supplies from reservoirs in a bid to give every area a limited supply, causing more interruptions.
It has warned that the drought could last for several more days.
Belfast City Council has opened three leisure centres to distribute drinking water, while free showers will be available on Wednesday.
NI Water said an unprecedented number of leaks caused by the thaw have been putting "big pressure" on its systems.
Many people have complained that it is impossible to get through to a helpline (08457 440088).
Among the areas worst hit are Belfast, Armagh and Coleraine.
Deputy First Minister Martin McGuinness said it was not good enough that some people had been left without water for so long.
"Obviously under the terms of the Financial Act that we put in place some time last year, the most vulnerable in our society - those that have been most badly affected by all of this - will have the right to make claims," he said.
"I think there will be a willingness on behalf of the Executive to ensure that the most deserving cases are supported financially."
Regional Development Minister Conor Murphy said he had been in contact with NI Water about the problems.
"I have been speaking to the chief executive of NI Water and they have assured me that they are working flat out to try and resolve all of these problems," he said.
"They have issues with contact because the volume of calls that has come in has put them under severe pressure.
"I have been constantly in touch with them to try and reassure myself that they're doing everything in their power to try and address this issue."
Belfast City Council is operating an emergency operation to help those without water.
Drinking water is available from tankers at three council sites: Avoniel Leisure Centre; Whiterock Leisure Centre and Olympia Leisure Centre from 8pm-10pm on Tuesday and from 9am on Wednesday.
It is limited to 20 litres per household and people must bring their own containers.
Drinking water will also be available from a tanker in the north of the city at the NI Water depot on the Westland Road.
All Belfast City Council Leisure Centres will be open on Wednesday and subject to water supplies will be able to provide free shower facilities.
Coleraine Leisure Centre will be open until 2200 GMT on Wednesday for shower facilities and anyone taking water containers can have them filled with drinking water.
Ruth Loney, who owns a small farm in Armagh, said there was like "a drought situation".
"There are elderly people in Armagh today carrying buckets of water and they are having extreme difficulty along the streets.
"There is also water pouring out of commercial premises and nobody realises that their business has burst pipes," he said.
"And unless there is help given to people who really need it we could be in a very serious situation."
Tiago Menezes returned to his house in Belfast to find the street has been without water for six days.
"After six days, it's starting to be a public health issue when you can't even flush the toilet," he said.
People seeking information about their water supply have complained to the BBC that it was almost impossible to get through to NI Water's phoneline, while the company's website has also been also running slowly.
Worried farmers have been among dozens of people contacting the BBC about their water supply problems.
Customers are asked to check the NI Water website for updates.
SDLP Regional Development spokesperson, Conall McDevitt described the communications system at NI Water as "inadequate and shambolic".
On Tuesday afternoon, NI Water said: "We would strongly urge all customers and property owners to check their premises, including vacant buildings, outbuildings and animal drinking troughs for any leaks and arrange for them to be isolated immediately and repaired as soon as possible.
"We are noticing that the majority of the leaks in the water system are currently on the customers' private water supply side.
"NI Water is currently inputting an additional 40% of water into our supply network to meet the unprecedented demand being experienced.
"We would also ask customers to conserve their use of water during this period of disruption in order to allow us to fully recharge our water network."
We have been without water for seven days. I have two young children, both under five, and it is proving exceptionally difficult to provide water for our family's needs, especially during a time when the whole family are at home. We contacted the emergency number a couple of weeks ago, when our water was off for three days. The water service did send someone out, but told us that as the mains pipe was frozen it was not their responsibility. Alastair McFarland, Ballinamallard
I would like to comment that despite your report citing Belfast and surrounding areas having severe problems that there are many people in the Dungannon and Coalisland area who have been without water for coming onto a week. Why have you failed to report this and why is this not considered enough of an emergency situation so that action is taken to distribute water as is being undertaken today in Belfast? No one I know can get in touch with NI Water to ascertain the action being taken to address this matter. Leontia Doran, Dungannon, County Tyrone
We have had no water since Christmas Eve, starting with the bath taps. We thought it was a frozen pipe at first, but then the taps downstairs stopped working too. Now we have no water at all, no shower or bath, can't even flush the toilets. Can't get through to Northern Ireland water as the number has been engaged all day and the website has been down most of today too. Claire, Dromore, Northern Ireland
We live in Coleraine and have no water. Can't get through on NI Water Helpline and their website keeps crashing. All local supermarkets and garages have sold out of bottled water and there doesn't appear to be any supplies available here from NI Water like there is in other towns. Total chaos. Tricia Roulston, Coleraine
We have had no mains supply for over 48 hours. Calling the emergency line is futile. To make matters worse supply of bottled water in local supermarkets has dried up. Johnny Bottomley, Bushmills
Our home has been without water since Christmas eve. The Housing Executive were informed early that morning and as yet no one has been in contact. We have been on the phone to NI Water constantly with no avail as it is either engaged or you are left waiting for the next available advisor, after 20 mins you have to wonder is there anyone there and give up. Other houses close by lost supply Monday night and it returned within a few hours; ours has had no such luck. There seems to be a serious lack of co-ordination and accountability. Gerry Andrews, Belfast
We live in Edenderry, Belfast and have no water in the village. I have tried in excess of 100 times to phone the Waterboard number. It is constantly engaged. Drove to North Belfast to get water for ourselves and an elderly neighbour to be told they had run out 10 minutes before we arrived! Heather Taylor, Belfast
Our water supply failed yesterday (Monday), morning. I called NI Water. I held on for 30 minutes before getting into the queue and then waited 10 minutes to speak to someone. The water supply was restored by the evening. However, considering the huge problem of such a deep freeze over the whole country, I accepted that there would be hundreds (in fact thousands) of people calling in. I am sure the NI Water got some things wrong, but on the whole they have done as good a job as could be expected in this extreme situation. Dr Raymond Cox, Portadown, Co Armagh
We are a family in East Belfast and have been without water since approximately 8.30am this morning. I took us until after 12pm to get through on the emergency water line and all we were told was that there was a problem with a reservoir, repairs were underway but there was no timescale to fix it. We cannot cook, wash, go to the bathroom etc and have no idea how long this will last for! Lisa, Belfast, Co Antrim