Many public and private water systems use a form of chlorine known as free chlorine to sanitize/disinfect the water they supply to their users. While having clean, safe drinking water does matter, and chlorine helps make water that way, certain problems may arise if chlorine concentrations get too high.
The USEPA has set the Maximum Contaminant Level (MCL) for free chlorine in potable water at 4.0 ppm.
This means water dispensed by a water stystem must contain less than 4.0 ppm free chlorine… or the system is in violation of Federal Law and subject to geting fined and/or shut down by the USEPA if their free chlorine readings continue to exceed Federal Guidelines.
How do they test for free chlorine residual?
As a general rule, most water treatment facilities use a method called “DPD Testing” to determine the free chlorine concentration in the water they distribute. Click here for more information on DPD Testing.
As of Spring 2007, though, the USEPA began allowing states to approve the use of an alternate, yet equal, faster method called SenSafe(tm) Free Chlorine Water Check. This method does not use liquids, tablets, powders or even meters, yet provides accurate free chlorine readings down to as low as 0.05 ppm. Click here for more information on SenSafe(tm) Free Chlorine Water Check.