Arkansas Department of Health & Human Services
Division of Health
Center for Local Public Health - Environmental Health Branch - Engineering Section

Chlorine is used in several forms as a disinfectant to kill any harmful bacteria which might be present in the water source. Chlorine is very effective in controlling and/or destroying harmful bacteria. The amount of chlorine that is to be used is based on several things. The first is the amount of water being treated. Second is the number or amount of contaminants that must be controlled. Third is the length of time the chlorine has to react in the water, before the water reaches the first customer.

Because of the way chlorine reacts with chemicals frequently found in water, the "chlorine" smell may actually indicate that not enough chlorine is being added. Increasing the amount of chlorine used at the treatment plant causes different forms of chlorine to be created in the water, which have less "chlorine" odor.

The water system is required by state or federal regulations to maintain at least a minimal level of chlorine in public drinking water. The normal range of chlorine in the water by the time it reaches the customer is 0.2 to 1.5 mg/l depending on the source type, size of system, type of treatment, and time of year. (Tony Ramick)