Temporary Free-Chlorine Conversion
Information for public water systems about temporarily switching from chloramine to free chlorine to disinfect drinking water, notifying consumers and TCEQ.
How Public Water Systems Disinfect Drinking Water
To protect public health, all public water systems (PWS) in Texas are required to disinfect drinking water before providing it to customers. Many PWSs use chloramine (free chlorine and ammonia), an effective disinfectant that persists over a long period of time, making it particularly valuable in areas with high temperatures.
Sometimes chloramine systems may need to complete a chlorine conversion, where the system removes ammonia from the treatment process and only uses free chlorine to disinfect the water. This common practice is used as preventive maintenance to kill bacteria that, though harmless when consumed by humans, can introduce unwanted taste and odor, and create issues with maintaining a disinfectant residual. TCEQ'S regulatory guidance document, Public Water Systems: Temporary Conversions to Free Chlorine (RG-631), discusses how to perform a successful free chlorine conversion.
Notify Customers
Before starting the temporary treatment change, the TCEQ recommends the PWS notify customers, including wholesale customers and their downstream customers. Information about the change, possible effects, and expected outcomes should be provided to customers.
- Public Notice Template and Language: Chlorine Conversion
- Public Notice Template and Language: Chlorine Conversion Spanish
- Chlorine Conversion Facts (GI-466)
- Datos Sobre el Proceso de Conversión de Cloro Libre (GI-466 esp)
Notify the TCEQ
Email TCEQ Water Supply Division 30 days before the start of the free-chlorine conversion. Include:
- PWS ID and name
- PWS contact name, title, and phone number
- Estimated start and end date
- PWS ID and names of customer systems
- Reason for the change in treatment
Send to DBP@tceq.texas.gov.
Assistance and Helpful Links
Information about Chloramine in Drinking Water (EPA webpage)
Controlling Nitrification in Public Water Systems with Chloramines How a PWS that uses chloramines can detect and respond to the degradation of the drinking water quality in a distribution system caused by nitrification.
Disinfection Byproducts in Public Water Systems What are disinfection byproducts, how do they form, and how can PWSs control them.
TCEQ's Drinking Water Watch holds the information we have for your PWS and is open to the public. This has contact information, sample sites, sample results, violations, and public notice due dates.
TCEQ's Financial, Managerial, and Technical (FMT) Assistance program offers free financial, managerial, and technical assistance to help public water and wastewater systems comply with regulations. To request assistance, contact the program at (512) 239-4691 or by email at FMT@tceq.texas.gov.