SAN ANGELO, Texas — The City of San Angelo’s Water Utilities Department will change how it disinfects the public water supply from May 30-June 28.
A COSA release said the department normally uses chloramine, a mix of ammonia and chlorine, to disinfect water.
Starting May 30, the department will use only chlorine, also known as “free chlorine,” a stronger disinfectant than chloramine. The annual temporary conversion from chloramines to free chlorine – a common practice for municipal water systems – ensures water safety in pipelines by ridding mains of residual microscopic organic particles. The process yields the highest quality of drinking water, the release said.
Water users may also notice a slight change in the smell, taste and appearance of their water that should subside after a couple of weeks. This may include a chlorine odor and slight discoloration. The water is still safe for normal usage during this time.
Customers may see more flushing of fire hydrants during the treatment period. Water lines with low flow have to be flushed more often to keep free chlorinated water moving through the system.
The department encourages kidney dialysis patients to talk with their equipment supplier, as different equipment may have varying needs and require adjustments. The City has contacted local hospitals to alert them of the change.
Some reverse osmosis systems are not designed to work with water that has free chlorine. Owners of RO systems should check their operation manuals or system manufacturers to ensure they will not be adversely affected by the change.
The process most fish tanks have for removing chloramines from water should do the same with free chlorine and need no adjustments. Fish tank operators should confirm that with their equipment supplier.
The water department will monitor chlorine levels and water-quality standards in the distribution system daily to ensure all regulatory standards are met.
Frequently asked questions
Why is our water system making these changes to our disinfection process?
Our water system normally uses ammonia and chlorine as the main means to disinfect water. Mixing the two chemicals forms chloramine, the most common disinfectant used in the United States for water systems that use lakes and rivers as their source. Occasionally, these systems must return to free chlorine as their disinfectant for a brief time to properly maintain the distribution system. Free chlorine works better than chloramine to control thin biofilms of organics and microbes that can build up in pipelines over time. This is common preventive maintenance used by most water systems that use chloramine as their main disinfectant.
When will this start and how long will it last?
The conversion starts May 30 and last approximately four weeks.
Will I need to do anything differently during this change?
No action is necessary. You can drink and use your water normally.
What changes to the water quality will I notice during this period?
Initially, you might notice more of a chlorine taste and smell to your water, especially in showers and sinks. Water also may also be slightly discolored in areas with low flows in water mains. These symptoms should lessen after a couple of weeks but may be present (though less noticeable) during the four-week span.
Will the City do anything to lessen the taste and odors we might experience during this change?
Yes, the City will implement procedures to reduce effects as much as possible. However, changes will likely occur and may persist. We will monitor free chlorine levels throughout the system each day to ensure they are at correct levels. You may also see more flushing of fire hydrants. Water lines with low flow must be flushed more often to keep free chlorinated water moving through the system. The Water Utilities Department does not like doing this during drought restrictions, but in some areas it will be required.
Is there a possibility of free chlorine bleaching my clothes?
Free chlorine is a stronger disinfectant than chloramine. Even though it may have more of a chlorine smell, the disinfectant residuals in the system will actually be lower than they are currently. We don’t expect problems with bleaching of clothes. If you have brand new clothes that have never been washed, you might wash them first in cold water to let their colors “set” before using a hot water wash.
Will this process improve the quality of my water once it is completed in four weeks?
Typically, after a change to free chlorine and then back to chloramine, less disinfectant is needed to maintain residuals in the distribution system. So, if you are sensitive to the taste and smell of chloramine, you should see an improvement in water quality after the conversion.
Is there a way to reduce or remove the chlorine taste and smell during this period?
Yes. A carbon filter is effective at removing free chlorine taste and smell, as well as chloramines. If you have an existing carbon filter on your faucet, reverse-osmosis system or cartridge under the sink, these should remove any additional taste and odor during this period. These are available at local retail stores. Some are inexpensive and easy to install.
Does the taste and odor from chlorine affect everyone the same?
No. The taste and smell of chlorine in drinking water does not affect some people at all. Others with a higher sensitivity to smells could be affected. Free chlorine can give water a “swimming pool” smell.
Who can I contact with questions or concerns?
Call the Water Quality Division at 325-481-2722 for more information.
(Editor's note: The attached video originally aired in 2022.)
