The LT2 rule requires a minimum chlorine residual at the entry to the distribution system. Which value is specified?

The LT2 rule requires a minimum chlorine residual at the entry to the distribution system. Which value is specified?

• A. 0.2 mg/L
• B. trace
• C. 0.5 mg/L
• D. 1.0 mg/L

Answer: (A)

A remaining disinfectant as water leaves treatment and enters the distribution system is essential to keep the water protected from microbial regrowth as it moves through pipes. The LT2 rule sets this minimum free chlorine residual at the entry to the distribution system at 0.2 mg/L. This value provides enough residual to maintain disinfection downstream without causing unnecessary excess that could raise disinfection byproducts or taste/odor issues. The other options aren’t the specified numeric requirement, and higher values aren’t what LT2 mandates for this entry-point criterion.

A remaining disinfectant as water leaves treatment and enters the distribution system is essential to keep the water protected from microbial regrowth as it moves through pipes. The LT2 rule sets this minimum free chlorine residual at the entry to the distribution system at 0.2 mg/L. This value provides enough residual to maintain disinfection downstream without causing unnecessary excess that could raise disinfection byproducts or taste/odor issues. The other options aren’t the specified numeric requirement, and higher values aren’t what LT2 mandates for this entry-point criterion.