The San Luis Obispo County Department of Public Works will temporarily change the disinfectant used in the Lopez Water Project distribution system beginning November 4.
Officials with the County of San Luis Obispo say the system will switch from chloramines, which is a combination of chlorine and ammonia, to free chlorine through December 2.
County officials say the water will remain safe to drink, although some customers may notice a slight change in its taste or smell.
They say this annual process helps keep the water system clean and maintain drinking water quality. Free chlorine is a stronger disinfectant used to remove bacteria that can build up inside water pipes.
The change will affect water delivered to Arroyo Grande, Pismo Beach and Grover Beach, along with the communities of Oceano, Avila Beach and Port San Luis.
Officials say most customers do not need to take any special action. Those who notice a chlorine taste or smell can reduce it by using a carbon filter, boiling the water or leaving it uncovered overnight.
The water will continue to meet federal and state drinking water standards throughout the process.