What is the recommended disinfection concentration for a water tank?

The recommended disinfection concentration for a water tank is based on ensuring effective pathogen reduction while avoiding excessive chemical residuals that could affect water quality. A concentration of 10 mg/L (or parts per million) of disinfectant, such as chlorine, is often sufficient for achieving a high level of disinfection in a water tank. The guideline suggests that this concentration should be maintained for a specified contact time, which allows for thorough disinfection before the level decreases to a residual of around 2 mg/L. This residual level is still effective in preventing regrowth of microorganisms.

Maintaining disinfection at this concentration balances efficacy, safety, and regulatory compliance, helping to ensure the water remains safe for consumption without leading to undesirable tastes or odors. In the context of the other options, higher concentrations may pose risks of chemical imbalance and potential adverse health effects, while lower concentrations may not effectively eliminate pathogens.