A siren warning system is being tested across Lincolnshire as the county makes sure it is prepared for flooding.
Forty-six flood sirens are placed around the county, mostly along the coast and several inland locations.
The tests, which are carried out annually at the end of the summer, will be heard on Wednesday.
Apart from the annual tests, the sirens normally only sound in the event of a severe flood warning being issued by the Environment Agency.
Emergency planner Ian Reed said: "We will test the sirens on a full cycle - they will sound five times in a 30-seconds-on 40-seconds-off cycle.
"We want to make sure there has not been any vandalism and they are in good working order as we go into winter."
The sirens can be sounded en masse or individually after a severe flood warning issued by the Environment Agency, with low-lying Lincolnshire at more risk than other areas.
In a real-life situation, the alarm would sound continuously with no breaks.