ORP, or Redox Potential, is a measurement of water’s ability to oxidize contaminants. The higher the ORP, the greater the number of oxidizing agents.

Checking ORP is a simple method to monitor the effectiveness of a sanitizer or the quantity of anti-oxidants in a liquid. In generalized terms for humans, a higher ORP is better for outside of the body, while a lower ORP is preferred for consumption due to the high anti-oxidant value.

There are numerous applications for ORP, each with its own specific optimum value. For example, the minimum ORP for pool & spa disinfection (set by the World Health Organization) is 650 mV. Though the WHO has not set a standard for ORP in drinking water, anything below -550mV is considered too strong and not recommended for drinking.