Water can be a very important factor to impair flocks’ biosecurity. Additional water disinfection greatly protects the farm from waterborne infections. It can be applied on a variety of ways. Most time the treatment is carried out at water tanks that are inside the farm, right before the distribution to the birds. Disinfectants are carefully selected to have some residual effect in order to also protect water distribution network of the farm. Water pH might also have to be adjusted. This good practice is coupled to frequent bacteriological and chemical laboratory tests to verify treatment’s efficacy. Animal Scientists and Vets supervise water treatment to prevent any detrimental effects on vaccines, vitamins or any other treatment that can be simultaneously delivered to the birds through the water. It costs approx. 50 euros per farm per year. An important benefit is that it reduces the on-farm mortality and morbidity at least by 2%. It can also improve bird performance by FCR 0,05. It can be applied to the whole sector and other types of poultry production. This practice protects the farm from water that might be obtained through an old or very big water distribution network. Use and dosage of disinfectants are applied according to local legislation for water for human consumption. Biofilm formation and drinkers’ leakage is controlled, thus reducing ammonia production in the farm. Birds’ welfare is also improved.