This test is available for compliance testing as described in the Federal Register (Vol 72, No. 47, Monday, March 12, 2007, p.11204, ITS Method D99-003).  Free Chlorine Water Check can now be treated as an equivalent to other free chlorine test kits.  States have the discretion to approve their use per authority at 40 CFR 141.74 (a)(2).  The original recommendation letter from the EPA stated: "We (EPA) believe that the ITS test strips will provide the regulatory community with a valuable option for monitoring free chlorine levels in drinking water."

"Municipalities now have a rapid (40 seconds), accurate, and low-cost option for regulatory compliance monitoring without the worries of indicator "bleach-out" or monochloramine interferences.  According to the EPA ; "The false positive and false negative rates were below 0-1%.  Method precision and accuracy were characterized in multiple drinking water matrices at varying chlorine concentrations.  For example, the validation studies showed that free chlorine recovery was approximately 100% and relative standard deviation (RSD) was generally below 20% for analysis of drinking water samples fortified with 0.1ppm of free chlorine or above; the chlorination level required by National Primary Drinking Water Regulations is 0.2ppm.  Finally, results did not vary across different lots of ITS test strips."