Effective January 1, 2004, the Arizona Department of Environmental Quality has
enacted the Disinfectant Byproducts Rule R18-4-214-02. The rule is designed to
enforce those water systems that chose to chlorinate to perform monthly chlorine
samples in the distribution system, and to annually test for TTHM (Total
Trihalomethanes) and HAA5 (Haloacetic Acids 5). The City has been chlorinating
its source water at the well sites for years. The City chlorinates at the lowest
possible levels between .02 and .04 parts per million. The City’s Public Works
Department chlorinates to maintain chlorine residual (kill) in the distribution
system, to protect the system from Coliform and E. Coli Bacteria.
HAA5 and TTHM testing is a chemical byproduct of chlorination and in high
amounts may be cancerous according to the United States Environmental Protection
Agency. The City of Show Low has been proactive with this rule and we have
already tested for these precursors last year. The results of the four tests are
Three of the tests
showed only a trace for TTHM’s and
the other sample were <5.
(Maximum Contaminate Level) for TTHM is 60 MCL. The Water Department will be
testing for these chemicals again this summer in the warmest month of the year.
For questions regarding the testing process and/or testing results, please
contact Courtney Carpenter, Water Supervisor at 928-532-4108.