Conversion of Drinking Water Disinfectant to Free Chlorine for the Five Cities Area
Author: Public Works
Date: 5/6/2025 3:44 PM
FIVE CITIES – The San Luis Obispo Department of Public Works will be changing the disinfectant in the Lopez Project distribution system from May 7 through May 28, 2025.
During this period, the disinfectant will be switched to free chlorine. This change will impact the water supply for the Cities of Arroyo Grande, Pismo Beach, Grover Beach, and the communities of Oceano, Avila Beach, and Port San Luis, as these areas may also be converted to free chlorine.
In response to the recent total coliform detection in the Lopez distribution line, the County will temporarily switch from its current chloramine disinfection method (a blend of chlorine and ammonia) to free chlorine. This process, commonly referred to as a "free chlorine burn," is an industry-standard practice. Free chlorine is a stronger disinfectant than chloramines and is particularly effective at targeting potential bacterial contamination within water mains. The County typically does this annually, and last implemented this procedure in November 2024.
While free chlorine is effective for microbial control, it is not suitable for continuous use in our system due to the increased potential for forming disinfection by-products (DBPs), which are regulated compounds that can result from treating surface water sources like ours. Chloramines remain our primary disinfectant under normal conditions to minimize DBP formation while still maintaining water quality.
Individuals may have varying sensitivity to the taste or smell of chlorine in water. While some may not notice any change, others might detect a taste or odor similar to that of a swimming pool. To reduce or remove free chlorine, you can boil the water, use a carbon filter, or let the water sit uncovered overnight to allow the chlorine to dissipate.
Chlorination is the most widely used method for disinfecting drinking water. Treating drinking water with disinfection, like chlorination, is essential for ensuring water safety and maintaining a residual disinfectant from the plant to the consumer’s tap. If you have any questions or concerns about your drinking water, feel free to contact your local water provider.
In response to the recent total coliform detection in the Lopez distribution line, the County will temporarily switch from its current chloramine disinfection method (a blend of chlorine and ammonia) to free chlorine. This process, commonly referred to as a "free chlorine burn," is an industry-standard practice. Free chlorine is a stronger disinfectant than chloramines and is particularly effective at targeting potential bacterial contamination within water mains. The County typically does this annually, and last implemented this procedure in November 2024.
While free chlorine is effective for microbial control, it is not suitable for continuous use in our system due to the increased potential for forming disinfection by-products (DBPs), which are regulated compounds that can result from treating surface water sources like ours. Chloramines remain our primary disinfectant under normal conditions to minimize DBP formation while still maintaining water quality.
Individuals may have varying sensitivity to the taste or smell of chlorine in water. While some may not notice any change, others might detect a taste or odor similar to that of a swimming pool. To reduce or remove free chlorine, you can boil the water, use a carbon filter, or let the water sit uncovered overnight to allow the chlorine to dissipate.
Chlorination is the most widely used method for disinfecting drinking water. Treating drinking water with disinfection, like chlorination, is essential for ensuring water safety and maintaining a residual disinfectant from the plant to the consumer’s tap. If you have any questions or concerns about your drinking water, feel free to contact your local water provider.
Conversión de Desinfectante de Agua Potable a Cloro Libre para el Área de Cinco Ciudades
