3.—(1) A derogation may only be granted—
(a)if it does not pose a potential danger to human health;
(b)the supply of water in question cannot be maintained by any other reasonable means; and
(c)it is limited to as short a period as possible (up to a maximum period of 3 years).
(2) If the enforcing authority refuses to grant a derogation, it must give reasons in the notice.
(3) If the enforcing authority grants a derogation, it must specify in the notice—
(a)the grounds for the derogation;
(b)the parameter concerned, previous relevant monitoring results, and the maximum permissible value under the derogation;
(c)the geographical area, the quantity of water supplied each day, the population concerned and whether or not any relevant food-production undertaking would be affected;
(d)an appropriate monitoring scheme, with an increased monitoring frequency where necessary;
(e)a summary of the plan for the necessary remedial action, including a timetable for the work and an estimate of the cost and provisions for reviewing; and
(f)the duration of the derogation.
(4) Before the end of the duration of a derogation (granted under this regulation), the enforcing authority must carry out a review to determine whether sufficient progress has been made (in relation to the plan and timetable for the necessary remedial action).