1.5 ADEM Drinking-Water Operating Rules (Division 335-7): Control Tests, Residuals, Pressure, Cross-Connections & Records

1.5 ADEM Drinking-Water Operating Rules (Division 335-7): Control Tests, Residuals, Pressure, Cross-Connections & Records

The WPI water exams test national practice and include an administrative content area on regulatory compliance, records and public notification. In Alabama, those duties come from ADEM's Water Supply Program rules, ADEM Admin. Code Division 335-7 (the version on ADEM's site is revised effective April 14, 2022). Rule 335-7-10-.02 ties the two programs together: community and non-transient non-community (NTNC) systems must employ operators certified under Division 10.

Required Water Quality Control Tests (Rule 335-7-10-.03)

These operational tests are in addition to monthly bacteriological compliance sampling and periodic chemical, radiological and DBP monitoring.

Disinfectant Residual Rules (Rules 335-7-10-.04 and 335-7-5-.17)

• Systems that disinfect must keep a residual that protects water throughout the distribution system. Using any disinfectant other than chlorination needs ADEM approval.
• Minimum in the distribution system: 0.2 mg/L free chlorine or 0.5 mg/L chloramines.
• Maximum at any point: 4.0 mg/L chlorine or chloramines and 0.8 mg/L chlorine dioxide.
• If the residual falls below the minimum (or rises above the maximum) and is not corrected within four hours, a treatment technique violation has occurred. The system must correct the treatment, notify ADEM by the end of the next business day, and give notice to affected customers in a newspaper of general circulation within 14 days (NTNC systems post notices).
• If the residual is not restored within 24 hours, collect bacteriological samples from the affected area. If they show contamination, the system has an acute violation with the matching public notice.
• With ADEM approval, systems may temporarily raise chlorine or chloramine residuals (not chlorine dioxide) to respond to main breaks, storm runoff, source contamination or cross-connection events.
• For groundwater, Rule 335-7-5-.17 requires a chlorine CT of at least 60 when average monthly turbidity is below 5 NTU and the source shows contamination risk, such as raw total coliform averaging above 20 but below 100 per 100 mL or raw fecal coliform or E. coli averaging above 5 but below 20 per 100 mL. The distribution residual must be measured and recorded daily.

Pressure and Hydraulics (Rule 335-7-7-.02)

A public water system must be designed and operated to supply at least 20 psi at the water system meter under all normal operating conditions. Projects that significantly affect hydraulics, such as new storage, sources, pump stations or main additions, need an ADEM permit before construction.

Cross-Connection Control (Chapter 335-7-9)

• A system must be designed, installed, maintained and operated to prevent contamination through any service connection. Serving premises where cross-connections may exist is prohibited unless they are properly controlled, and any connection that could admit unapproved water needs ADEM approval.
• A suitable backflow prevention device must be installed on each new service connection and on each customer connection replaced after January 1, 2006 (replacement means removing and reinstalling the meter and service line).
• Community systems must formally adopt a written cross-connection control policy, provide it to customers on request, and run an inspection program, keeping records of health hazards found and corrective actions for at least five years.
• The supplier must deny or discontinue service if a required device is not installed or properly maintained, until the problem is corrected to the satisfaction of the supplier and ADEM.

Reports (Rule 335-7-10-.06)

• The monthly operating report is due by the 10th of the following month, contains the required control-test results and daily minimum disinfectant levels, and must be signed by a certified operator. Keep a copy available for inspection.
• Chemical analysis records are due by the 10th of the month after the monitoring period ends.
• Notify ADEM within 24 hours of filtered surface water above 1.0 NTU, finished groundwater above 5.0 NTU, a residual below 0.2 mg/L free chlorine or 0.5 mg/L chloramines, or potential waterborne disease outbreak.
• Report any exceeded operational evaluation level for disinfection byproducts within 10 days after the end of the quarter.

Record Retention (Rule 335-7-10-.05)

Worked Scenario

At 6:00 a.m. a routine check at a dead-end tank site reads 0.1 mg/L free chlorine. The operator flushes the main and boosts the feed, and by 9:30 a.m. the residual is 0.4 mg/L. Because the residual was restored within four hours, no treatment technique violation occurred, but the low reading still must be documented and, under Rule 335-7-10-.06(4), reported to ADEM within 24 hours. Had the residual stayed low past four hours, the system would owe ADEM notice by the end of the next business day and public notice within 14 days; past 24 hours, it would also collect bacteriological samples from the affected area.