CRESTA swimming pool in Chard has closed because of a "maintenance issue".
The leisure centre's closure was announced on social media this morning by 1610, who run the county council-owned pool.
A spokesman for Cresta said: "Due to unforeseen circumstances the pool will be closed Monday morning 20.03.17.
"We will update our webpages when we have more information. We advise calling the centre on 01460 64084 before your next visit.
"We apologise for any inconvenience caused and appreciate your patience."
The spokesman later added: "It is neither a health and safety or a staffing issue. Unfortunately it is a maintenance issue and we are currently awaiting an update on this.
"We are hoping this will be a short closure and that will we be open again by the afternoon, but once we know more we will update our webpages and do our best to contact all lessons and regular swimmers."
Last month, Somerset County Council pledged £150,000 towards much needed repairs to the pool.
This followed a petition set up by residents in January demanding SCC commit ot the pool's future.
Cresta Swimming Pool, which is in Zembard Way, Chard, was forced to close for 16 days at the end of 2016 for an investigation into problems with air quality at the pool.
A survey undertaken at the end of 2015 estimated that the total repairs required for the pool could cost in excess of £1million.
Cllr Amanda Broom said: "As soon as this was posted on Facebook I have been trying to find out the reasons for the closure.
"Strangely my post was removed, but after chasing this morning, 1610 have now responded. There should be more clarity with users as to why the pool was closed."
Tracy Slater, who started the petition earlier this year, said: "None of the swimmers were told about this on Sunday, so it doesn't sound like planned maintenance.
"It is so disappointing to see it closed again - and frustrating for everyone who uses it."
A later statement revelead the pool was set to reopen at 3pm.
It said: "The swimming pool will be reopening at 3pm today 20.03.17.
"Please check out the timetable for the next public session.
"We appreciate your patience during this closure."