Engineers have been working through the night to try to restore water supplies to Southern Water residents across Hampshire.
The company says the demand for water is currently outstripping its ability to treat it meaning water supplies are restricted to thousands of homes.
Areas affected include Southampton, Eastleigh, Hedge End - and Chandlers Ford.
Southern Water is urging its customers who still have water to only use it when necessary.
In a statement, the company said: "We know it’s a lot to ask, but if you still have water, only using it when necessary will reduce the overall network demand and massively help restore usual service for customers."
It added: "Demand is outstripping production, but we’re working as hard as possible to restore your supplies to normal. We really do appreciate how hard this is for you, especially in the run-up to Christmas."
Bottled water stations have been set up for those affected. They are open from 8am today and are located at:
The Ageas Bowl, SO30 3XH
East Winchester Park & Ride, SO23 9NP
Places Leisure Eastleigh, SO50 9NL
During the loss of water, Southern Water is offering priority water delivery to homes for vulnerable people and others who might be eligible too.