Regulation 17 makes provision for any relevant person (owner, user, or other person responsible for a private supply) to apply to the local authority for an authorised departure (called a derogation in the Directive) – that is, to supply water to a lower standard on a temporary basis while remedial action is taken as part of an agreed and timed programme of work. The European Commission (EC) has advised that provision for derogations was included in the Directive to allow member states time to take necessary steps to comply with all of the standards. The Directive was published in 1998 and, therefore, the EC considers that it should now be unlikely that any member state should require new derogations.
The Inspectorate published guidance around this issue in June 2013: Regulation 17: Authorisations of different standards (PDF 263KB)
The EC has clarified their position further and the provision to apply for derogations still exists, and, if specific circumstances arise such as a new parameter being detected, the local authority can consider issuing authorisations, assessed and evidenced on a case by case basis. A local authority considering granting an authorised departure should approach the Inspectorate for advice on the specific case under consideration.