Oxidation-Reduction Potential (ORP)

ORP measures the water’s ability to accept or release electrons and is typically used to determine the oxidizing or reducing potential of a water sample, indicating possible contamination. The more positive the ORP value, the greater the tendency the water has to oxidize organisms or other material in the water, therefore killing or destroying them.

ORP measurement is integral to water quality because it indicates how sanitized or contaminated water is.  ORP is used for drinking water, swimming pools, spas, cooling tower disinfection, groundwater remediation, bleaching, cyanide destruction, chrome reductions, metal etching, fruit and vegetable disinfection and dechlorination.

ORP monitoring is widely used within the water treatment and food processing industries to ensure that water is free of contaminants and safe to recycle or consume. In order to be safe to consume, recycle, or come in contact with our skin, water is treated with a sanitizing agent to have a higher oxidation potential, which then produces a higher ORP reading.  Understanding ORP values helps to determine water quality, allowing operators to decide what treatment processes are required.  Excess chlorine in wastewater effluent will result in a large positive value of ORP and the presence of hydrogen sulfide will result in a large negative value.