Treated sewage water may be used only once its risks have been identified and mitigated, taking into account the crop type, its growth stage and whether water touches the edible part, and periodic analysis confirms the treatment remains effective. Water quality meets prevailing regulations or, if there are none, the WHO wastewater, excreta and greywater safe-use guidelines (2006), judged by indicator organisms, with E. coli the recommended one. Unless a stricter rule applies, the WHO verification level of no more than 1000 E. coli per 100 ml of treated wastewater is adopted, and any stricter local threshold is dealt with in the risk assessment. Where water may be polluted, analysis shows it complies. Crops are never irrigated with untreated sewage water. Not applicable where the farm uses no treated sewage water.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.