Langsett, Scout Dike, Winscar and Ingbirchworth - all owned by Yorkshire Water - are included in the pre-summer ‘Be Water Aware’ campaign.
Despite warnings about the dangers reservoirs can pose, such as cold water shock, currents and under-the-surface machinery, people are still being seen entering the water.
Last summer, a man in his 30s was rescued from Langsett, although local reservoirs claimed five lives in 2019 and 2020 - all deemed accidental due to swimmers not knowing of the dangers.
Alastair Harvey, lead countryside and woodland advisor for Yorkshire Water, said: “We know as the weather improves the frequency of people getting into the water will increase and we are backing the campaign in a bid to raise awareness of the dangers open water poses.
“It is vital those visiting our sites stay out of the water, no matter how tempting it may appear.
“Cold water shock, undercurrents and operating machinery all pose dangers to people deciding to enter the water.
“Latest figures indicate almost 50 per cent of the total 254 accidental drowning deaths in 2020 had no intention of entering the water.
“If people see others in difficulty in the water, they should contact the emergency services on 999 as they are trained to deal with such events.”
Firefighters are delivering classes in Barnsley schools to highlight the campaign - and danger - of entering water due to recent summers’ incidents and last July’s spate of call-outs to Stairfoot Quarry, which was eventually fenced off to prevent access.
A spokesperson for South Yorkshire Fire and Rescue said: “Our message is simple - people should stay out of the water unless they are part of an open water swimming group, of which there are several in and around South Yorkshire.
“Unless you are part of one of these groups, you shouldn’t be going anywhere near open bodies of water such as quarries, lakes and reservoirs.
“To start with, lots of these places are privately owned, so people shouldn’t be going there anyway - beyond that, there are a wide range of risks with jumping into open water.
“Firstly, the water is almost always colder than it looks - bodies can temporarily shut down from cold water shock which can stop even strong swimmers.
“Secondly, you don’t know what’s under the surface.
“Finally, there are often hidden currents in bodies of water that can overpower even the strongest of swimmers.
“It’s just not worth the risk.”