They fear road users, especially cyclists and motorcyclists, are being put at risk by thieves stealing the metal gulley covers.
A series of thefts in recent months has created major road hazards resulting in repair and replacement bills running into thousands of pounds.
Police believe the covers are being stolen for their scrap metal value and have appealed for information.
During the past week, around 20 covers have been stolen including 15 overnight on Friday. They were taken from locations on the A458 Shrewsbury to Bridgnorth road and the B4380.
Twelve were taken from Berrington and Cross Houses, five in Cressage, one at Sheinton and another two from Leighton.
The owners are Shropshire Council and replacement will cost around £5,000.
Police Constable Dave Harte, the Local Policing Officer for Shrewsbury Rural South, said today: “The public can play a big part in helping us arrest the offenders.
“We urge people to phone the police immediately if they see roadside drains or gulleys being tampered with or worked on.
Even if they appear to be council staff, call the non-emergency 101 number so we can check them out in situ.
“We also urge scrap metal merchants to notify the police if they are offered such items.”
PC Harte said the thieves were putting lives at risk. “Gaping holes are being left in the roads putting the public in danger.
Any information which will assist our investigations will be most welcome.”
Information can also be given to the anonymous Crimestoppers independent charity by calling 0800 555 111.
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