How can i get rid of water on the knee naturally?

Joint effusion: It sounds like you are talking about a an "effusion" or build up of inflammatory cells and fluid around your knee. The treatment of "water" on your knee varies with the cause. If arthritis is the cause, Acetaminophen or a NSAID may help. Sometimes, your doctor can use a needle to drain this fluid. Rarely, the fluid is secondary to an infection and requires antibiotics. See your doctor.