To maintain the effectiveness of Round Rock’s water distribution system, the City of Round Rock will be conducting a temporary disinfectant conversion, switching from its usual disinfectant, chloramine, to free chlorine for approximately one month starting in late May.

“This process will help ensure that we continue to provide safe, high-quality drinking water to every household and business in our community,” said Public Works Executive Director Michael Thane.

The system maintenance is planned to take place May 27 through June 27. During the conversion, residents may notice a temporary change in the taste or smell of their water — some may detect a more “chlorine-like” scent, similar to what’s found in swimming pools. The water will remain safe to drink, bathe and to use for plant watering.

Why is this needed?

To protect public health, Texas cities are required to maintain appropriate levels of disinfectants—either free chlorine or chloramines (a combination of chlorine and ammonia)—throughout the entire water distribution system. These disinfectants are critical in eliminating harmful pathogens as water travels from treatment facilities to residents’ taps.

The City of Round Rock previously used free chlorine as its residual disinfectant through the early 2000s, but has since employed chloramine due to its long-lasting stability and lower potential for disinfection byproducts. However, over time, cascading distribution system challenges could occur with the exclusive, extended use of chloramine, especially in warmer months or in systems with complex distribution patterns. To mitigate these concerns and maintain required disinfection throughout the system, a temporary conversion to free chlorine is a recognized industry best practice.

This temporary change helps Round Rock keep its water system clean and working properly by:

• Clearing out buildup that can collect inside pipes over time and make disinfectants less effective.
• Preventing bacteria growth that can happen when using chloramine for long periods.
• Making sure disinfectants reach every part of the system, especially areas where water may not move as much.

In accordance with Texas Commission on Environmental Quality (TCEQ) guidelines, the City of Round Rock collects daily water samples from locations across the community to check that chlorine residuals are strong enough throughout the entire water system to protect against bacteria but not so high that they pose a health risk.

What to expect

The duration of the free chlorine conversion will last approximately 30 days. For customers who notice a difference in taste or smell during this time, the water can be stored in an open pitcher and placed in the refrigerator to allow the chlorine to naturally dissipate and become less noticeable. Water filtration systems, such as carbon filters in a water softener or shower head, are effective tools for customers to remove chlorine from the water in their home.

During the free chlorine conversion, Public Works crews will flush water through hydrants in targeted areas of the city to ensure newly treated water reaches all parts of the system. This helps maintain high water quality and clears out any stagnant water, especially near the beginning and end of the month-long conversion.

Hydrant flushing during the conversion can stir up harmless sediments, causing cloudiness or discoloration. If this occurs:

• Run cold water from faucets (bathtubs or by hand watering your backyard from an outdoor faucet) for several minutes until it clears. If it does not clear, please fill out an online Water Quality Service Request Form.
• Avoid doing laundry if water appears discolored (most likely to occur May 27-29) to prevent fabric staining. First, run a bathtub faucet to check for discoloration. If the water runs clear, it’s safe to do laundry.

Note for special groups (dialysis centers, fish and pool owners)

Dialysis providers and hospitals are trained to adjust their treatment processes when disinfectants change. The City has been working to notify local dialysis centers and similarly impacted facilities about the switch to free chlorine.

The water is safe for most pets like cats and dogs. However, if you have fish, amphibians or other aquatic life, the water must be treated with a dechlorinator or water conditioner before use, just like with chloramines.

Pool or hot tub owners do not need to change maintenance routines. Whether the water uses chloramines or free chlorine, customers should continue maintaining appropriate chlorine levels to prevent algae and bacteria growth.

For more information and a list of FAQs, visit roundrocktexas.gov/chlorinerinse.