Thames Water has explained why hundreds of homes are without water or experiencing low pressure.
The issues were reported late on Friday night according to customers on social media.
People who live in the RG5, RG6, RG9 and RG10 parts of Reading are being told engineers are working to fix the problem.
The water firm has setup a bottled water station at Waitrose on London Road, Tywford but it asking customers to only take what they need.
Long queues were reported getting into the supermarket.
In a statement Thames Water said, "We’re really sorry if you have low pressure or no water this morning, as a result of technical problems at Sheeplands Water Treatment Works in Wargrave.
"Our engineers are working to get things back to normal as soon as possible.
"Our team have specific measures in place to safely distribute water on a drive-through basis."Please don’t ask for more than you need. The water is for essential use, like drinking, cooking and hand washing.
"If you have a neighbour who’s unable to get to our drive-through water station, please let us know and we’ll do our best to make sure our limited supplies are fairly handed out."
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