Texas chlorine residual requirements

Who has to chlorinate

• All ground water must be disinfected before distribution. 30 TAC §290.42(e)

Minimum residual

• Entry point: at least 0.2 mg/L free chlorine, or 0.5 mg/L chloramine measured as total chlorine. 30 TAC §290.110
• Distribution system: at least 0.2 mg/L free chlorine, or 0.5 mg/L chloramine measured as total chlorine. 30 TAC §290.110
• Falling below the distribution minimum in more than 5.0% of the month's samples for two consecutive months is a treatment technique violation. 30 TAC §290.110

Maximum

• The running annual average in the distribution system may not exceed the 4.0 mg/L maximum residual disinfectant level. 30 TAC §290.110

How often to test

• Ground water or purchased water systems with fewer than 250 connections and fewer than 750 people: at representative distribution locations at least once every seven days. 30 TAC §290.110
• Systems with 250 or more connections or 750 or more people: at least once a day. 30 TAC §290.110
• Every system: at the same time and place as each bacteriological (coliform) sample. 30 TAC §290.110

Test kits and methods

• Residuals must be measured to an accuracy of ±0.1 mg/L. Color comparators may be used for distribution samples only, with current reagents and an unfaded, clear comparator. 30 TAC §290.110

Reporting

• Ground water and purchased water systems complete a Disinfection Level Quarterly Operating Report (Form TCEQ-20067) every quarter. 30 TAC §290.110
• Community and non-transient non-community systems submit it by the 10th of the month after the quarter: April 10, July 10, October 10 and January 10. TCEQ
• Transient non-community systems keep the completed reports and provide a copy if TCEQ asks. 30 TAC §290.110

How long to keep records

• Distribution disinfectant residual results: 3 years. 30 TAC §290.46
• Chemicals used and water volumes treated: 2 years. 30 TAC §290.46
• Microbiological results, and lowest daily residuals for systems doing 4-log monitoring: 5 years. 30 TAC §290.46
• Chemical analyses, sanitary surveys and sample siting plans: 10 years. 30 TAC §290.46

Parks, campgrounds and seasonal systems

• TCEQ's DLQOR guide works through a mobile home park with 14 homes and 47 people: one coliform sample a month with its residual, plus weekly residual-only checks, for four residual samples in January 2020. TCEQ RG-407
• Transient non-community systems using only ground water or purchased treated water are exempt from the operator licensing requirements; ground water systems with up to 250 connections otherwise need a Class D operator or higher. 30 TAC §290.46

Keeping the log in Texas

A weekly distribution reading plus one with each coliform sample is the minimum for a small Texas system. Many operators check daily anyway, because a feed problem caught on day two is easier to explain than one found on day seven. Whatever the frequency, each reading needs the date, time, location and result so it can go straight onto the DLQOR.

Print a dated month with the chlorine residual log sheet, or build a sheet for your whole round with the daily water system log sheet.