Regulations were made in December 2002 increasing the area designated as nitrate-vulnerable zones (NVZs), to 55 per cent. of England. The regulatory impact assessment made at the time estimated the total annual cost to farmers of complying with the NVZ regulations to be £21.7 million.
A consultation on proposals to revise the NVZ regulations closed on 13 December 2007. The partial regulatory impact assessment published with that consultation estimates annual costs to farmers of implementing the proposals if they were to proceed, (based on a proposed 70 per cent. NVZ area) to be in the range of £52.8-£105.9 million; it is estimated that mitigating measures identified in the assessment could reduce this to £35.5-£80.8 million.