I can currently cycle just over 19 mile in 1 hour and I will carry just a bottle of water for any distance under 20 miles. Generally, I will start carrying electrolyte drinks and maybe a cereal bars for longer rides of well over 2 hours, dependant on torrain as well.
My longest single ride so far has been a 132 mile trip from Manchester to Abersoch in Wales and on that hottish day, I drank about 3.5 litres of sports drinks and a few cups of coffee together with 4 ham sarnies, 2 flapjacks, 2 bananas, half a soreen loaf and a sausage and egg butty durring a lunch time stop.