Frequent Questions

Does the EPA have a Definition of the Word Residual when using a Liquid Disinfectant or a Liquid Santizer to maintain a Residual effect?

U.S. EPA utilizes the term “residual” in many contexts and throughout its various environmental program areas (see Glossary of terms in the context of “residual”). From the various definitions of the term, “RESIDUAL” means “what remains (in excess) after a process is considered complete”. Therefore, to make complete sense, the term residual must be accompanied by what is being discussed ( Risk, contaminant, Chlorine, other reagent or disinfectant, waste, etc.). Hence the use of the terms such as:


  • Soil residual contaminant level
  • Chlorine residual
  • Residual solid waste landfills
  • Coal combustion residual
  • Residual risk management
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