This guide is for water companies. It will also apply to other operators of standalone water discharge and groundwater activities if they’re required to carry out OSM.
The Environment Agency sets numeric discharge quality limits in environmental permits to make sure discharges comply with water quality objectives.
Water companies must collect and analyse samples of permitted discharges that are subject to numeric quality limits. This is called OSM. It includes discharges to surface water and groundwater.
This guide explains the rules that apply to OSM. It sets out the minimum standards needed to meet the requirements of OSM permit conditions.
The Environment Agency makes sure water companies carry out OSM specified in their permit conditions. Operators must carry out OSM to a standard that meets the requirements for compliance assessment and water quality planning.