There is no fixed limit or exact amount of water that you should take while working on a level 1 fitness recumbent bike. Water intake would basically depend on how much fluid you lose while doing your work out. Of course, it is important to drink water while exercising to prevent dehydration. This is because dehydration can cause muscle cramps and pain. Also be sure that you are well hydrated when you start your routine on the recumbent bike. As you increase the levels of the fitness bike and therefore the intensity, you would have to increase your water intake to replenish the fluids that you lose.