A faulty valve has left homes in parts of Glasgow without water.
Scottish Water said it had received a high volume of calls from residents in the west, south and north of the city on Saturday morning.
The company apologised and said in a statement: "We have identified a fault with a valve on our network which caused an interruption to the water supplies for customers in several areas of Glasgow this morning.
"The issue has now been resolved and the network is starting to recover; however, it may take a few hours for the system to fully recharge.
"While the supply is being restored please be aware that you may experience no water supply, low/intermittent pressure, or discoloured water."
Scottish Water said the issue threatened the supplies of around 20,000 customers.
A spokesman for the company said: "We would like to apologise to customers who have experienced disruption to their water supply this morning.
"We understand the inconvenience this causes and appreciate everyone's patience while our team completed a repair in order to restore supplies as quickly as possible."