Cookstown police are hunting vandals who broke into the town's Health Centre and flooded the building.
Local Ulster Unionist Councillor Mark Glasgow strongly condemned the incident.
"The people who carried out this attack on our Health Centre must be brought before the courts and judgement must be brought to the ones who carried out this disqusting attack," he tweeted.
Police are appealing for information about the vandalism.
"At some point last night individuals broke into Cookstown Health Centre with the sole aim of destroying the place," police said in a social media post.
"Those that broke in specifically went to the roof space water storage tank, removed the sealed lid and destroyed the ballcock mechanism in the tank.
"With the water constantly flowing they then diverted the external overflow pipe to make the overflowing water empty inside the building.
"By sheer good fortune a member of staff went into the building this morning on a separate task and spotted the flooding inside. There is significant water damage.
"If this hadn’t been discovered until Monday the majority of Cookstown Health centre would have been completely destroyed, medical equipment, notes, medicines, patient records and computers would all have been lost to water damage.
"This wasn’t vandalism, this was a targeted attack on the people of Cookstown and anyone you uses medical services and the health centre in this town, the only aim was to destroy the Health Centre.
"We want to know who was involved. Did you see individuals in the car park on the evening or night of Friday 14th September or early hours of Saturday 15th? Did you see anyone on the roof of the health centre? Or have you seen individuals hanging around the health centre in recent weeks or days?
"Don’t post names or info as a reply, send us a PM. There are serious burglary offences here and we want to see those responsible caught and prosecuted. We are currently analysing CCTV footage of the area and town.
"Those who wish to destroy essential medical facilities in our town need to be standing in front of a judge preparing for a prison sentence, help us put them there. Share this post with others, someone out there knows who was responsible."