Water in IPPC and IPC
Pollution Prevention and Control (see emissions overview) introduced systems of prior consent which require process operators to include emissions to controlled waters and sewers in their Permits and Authorisations.
If your site or any part of it came under this licensing regime, then you will be monitoring the water leaving via surface water drains or sewers, and reporting statistics to the Environment Agency as required.
The way you use water and the measures you take to minimise its use are likely to be specifically mentioned in the conditions of your Permit.
Being part of integrated control, your discharges either direct to controlled waters or to the sewerage system will be regulated under the relevant Acts (see Register of Environmental Legislation)