The Produce Safety Rule (PSR) requires growers to initially establish a Microbial Water Quality Profile (MWQP) for each untreated agricultural water source used during growing activities of covered produce (other than sprouts) using a direct water application method and conduct annual surveys for that water source in subsequent years. The water quality profile is based on the levels of generic E. coli in your agricultural water. There are different requirements for agricultural water that comes from surface or ground (well) sources.
Several tools were developed to make it easy to calculate the GM and STV and to determine if your water meets the criteria for appropriate application to produce before harvest. The tools were also designed to assist you with making water management decisions if your water does not meet the criteria in the Produce Safety Rule.