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Disinfectant Residual Reporting for Public Water Systems

Guidance and forms for public water systems for monitoring and reporting of disinfectant residuals in the distribution system.

All community and nontransient noncommunity public water systems (PWS) that use only purchased water or groundwater must regularly monitor the level of disinfectant in the distribution system and use the Disinfectant Level Quarterly Operating Report (DLQOR) to report this information to the TCEQ every quarter. TCEQ regulatory guidance, Monitoring, Analyzing, and Reporting of Free Chlorine and Chloramines (RG-407)  contains detailed information for systems related to requirements and procedures for the monitoring, analysis, reporting and compliance with disinfectant residual rules and regulations. General information may also be found on Frequently Asked Questions about DLQOR.

Note: If your PWS treats surface water or groundwater under the direct influence of surface water (GUI), do not use the DLQOR form. You must submit the Surface Water Monthly Operating Report (SWMOR).

Disinfectant Residuals - Free and Total Chlorine

Systems are required to maintain a minimum level of disinfectant to kill microbes that can cause acute diarrhea, nausea, or other life-threatening illnesses.

The minimum level of free chlorine required in the distribution system is 0.2 milligrams per liter (mg/L), if free chlorine is used. The minimum level of total chlorine (chloramines) required in the distribution is 0.5 mg/L, if chlorine and ammonia are added to the water to form monochloramine.

The maximum level of disinfectant was set by the Environmental Protection Agency (EPA) because of increased risks of cancer to people who drink water with very high levels of free or total chlorine for an extended period of time. The maximum residual disinfectant level (MRDL) is 4.0 mg/L, which is based on a running annual average of all samples in the distribution system. A single high sample will not necessarily put the system in violation, as long as the annual average is below 4.0 mg/L.


The DLQOR may be submitted electronically or a paper copy may be mailed to TCEQ. To learn more about submitting your DLQOR form electronically, please visit the Electronic Environmental Reporting (E2). The electronic submission process is recommended but we will continue to accept the paper form through the mail. Please use the most up to date version of the pdf form located below.

The DLQOR (TCEQ-20067) is available as a fill-in-the-blank PDF file. This PDF file:

Disinfectant Residual Worksheets

Optional worksheets are provided for your use to keep track of disinfectant residual results for your PWS. These worksheets are designed to assist you; you do not need to send them in to us.

  • for a PWS with 750 customers or fewer
    PDF · Word
  • for a PWS with 751 to 4,900 customers
    PDF · Word
  • for a PWS that collects samples daily
    PDF · Word

Public Notice Requirements

All public notices for DLQOR violations can be found at Public Notice Language for Drinking Water Compliance, under Other Drinking Water Rule Violations.

Assistance and Helpful Links

TCEQ's Drinking Water Watch holds the information we have for your public water system 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.

Temporary Free-Chlorine Conversion can assist PWSs make a temporary switch from chloramine to free chlorine.