A water main has burst in Altham affecting supplies to up to 10,000 homes.
United Utilities said the 36-inch pipe burst at around 11pm last night on Burnley Road, near Martholme Grange.
The pipe transports water supplies from an underground storage reservoir in Martholme Grange to homes in the BB5 area of Accrington and the neighbouring BB1 area of Blackburn.
Pensioner Terry Clifton, 79, a carer for his disabled wife Margaret, said his water supply was completely cut off.
“We have had no water,” he said. “The frustrating part is finding out what's happened from United Utilities. We couldn't make a cup of tea or prepare lunch. I have prostate cancer and my wife is paralysed down her left side so it is hard work.”
United Utilities' call centre took around 150 calls on Tuesday night from customers, the majority affected by low water pressure.
Traffic flow wasn't affected on Wednesday morning apart from slight congestion as people looked out from their cars as engineers worked to fix the pipe.
Engineers were looking at options to re-route local supplies through an alternative pipe, while repairs to the damaged pipe continued as ther Observer went to press.
Large water tankers also pumped supplies directly into the local network, to keep taps flowing.
Polly Rourke from United Utilities said: "The damaged pipe serves up to 10,000 properties but this is the maximum number of homes that this can affect. We are hopeful that water loss or low pressure can be confined to a far smaller number of homes. To date, we have received around 150 calls from the public.
"We are very sorry for the inconvenience and can assure customers we are working as quickly as possible to restore normal service."
Customers can get updates on the situation by checking the United Utilities website Emergencies page at www.unitedutilities.com/emergencies