The City of San Angelo’s Water Utilities Department will change the disinfectant used in the public water system from chloramine to free chlorine beginning June 1 for approximately four weeks.

jenn durfey

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 these 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 will start June 1 and last approximately four weeks.

Will I need to do anything differently during this change? No action is necessary.  You may drink and use your water normally.

What changes to the water quality will I notice during this period? Initially, you may 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.

I have a fish tank. How will it affect my fish? We recommend you check with your equipment supplier. The process you have in place to remove chloramines in the water should also remove free chlorine. No change or adjustment should be needed.

I’ve heard this can affect kidney dialysis machines. Is this true? We recommend you check with your equipment supplier. Different equipment may have different needs or adjustments.

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.

Whom can I contact with additional questions or concerns? Please call the Water Utilities Department at 325-657-4300 for more information.