Byelaws are being introduced at Baitings and Ryburn reservoirs to stop people risking their lives by getting in the water.
Yorkshire Water says there were scores of incidents this summer where people put themselves in danger by swimming or playing in reservoirs .
The new laws will prohibit anyone from going in the water.
Bans are also being introduced on consuming alcohol, overnight cmaping, lighting fires, dangerous driving, littering, fly-tipping, and dog fouling - something the company describes as “a major problem”.
Hazel Clemmit, from Yorkshire Water, said: “We’ve spent millions opening up some of our stunning reservoir sites, which attract thousands of people every week who use them for their enjoyment. Sadly, despite our best efforts, the irresponsible behaviour of small minority can on occasion ruin it for the majority. We hope that these byelaws will encourage people to do the right thing and adhere to the rules, without us having to use them punitively. However, if and when we need to, people should be left in no doubt that we will enforce them in order to preserve our sites, protect water supplies and ensure the vast majority of people who are doing the right thing can continue to enjoy and make the most of them.”