Dozens of operations at Royal Alexandra Hospital (RAH) in Paisley have been postponed due to a problem with the water supply.
Elective surgery for 84 patients on Thursday and Friday has been postponed while emergency patients are being diverted to other hospitals, NHS Greater Glasgow and Clyde (NHSGGC) said.
Discoloured water was noticed coming from taps at the Renfrewshire hospital earlier this week.
Read more: Meet the only doctor in Scotland training to be a rural general surgeon
It is thought a build-up of sediment in water tanks caused the problem, with Scottish Water working to flush the hospital's systems.
The health board said staff are using bottled water, hygiene wipes and gel to maintain infection control measures.
Dr Linda de Caestecker, director of public health, said: "I want to reassure existing patients in the RAH that they are safe and we have ensured the highest standards of infection control and patient care.
"Patient safety is our priority and our staff will continue to deliver the highest levels of care despite the challenges they face."
NHSGGC said it will "work round the clock" with Scottish Water to ensure the hospital is fully operational again as soon as possible.
Read more: Meet the only doctor in Scotland training to be a rural general surgeon
Scottish Water said water "no longer appears to be discoloured" but more sampling is being carried out.
The cause of the discoloured water is believed to be naturally-occurring manganese.
Peter Farrer, Scottish Water's chief operating officer, said: "The water which is entering the hospital from our network no longer appears to be discoloured, and in the meantime we are aware that the hospital is taking some precautionary steps.
"Further sampling is being carried out. We will continue to liaise with, and assist the health board, to return their internal hospital water tanks to normal as a matter of urgency.
"The cause of this discoloured water is believed to be naturally-occurring manganese which, in the quantities commonly found in drinking water, is harmless.
Read more: Meet the only doctor in Scotland training to be a rural general surgeon
"The appearance of such discoloured water has been an occasional, seasonal issue in recent years in parts of Renfrewshire. To address this, we are carrying out a £16 million upgrade of the Muirdykes Water Treatment Works, which will help tackle the issue of discoloured water caused by naturally-occurring manganese in the area. This is due to be completed in 2017.
"In the meantime, we will shortly be commencing a programme to flush water mains and help address the issue."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules here