5.—(1) A local authority may reduce the sampling frequencies required for a parameter (other than for Escherichia coli (E. coli)) under Part 1 or 2 of this Schedule provided that—
(a)the results from samples taken in respect of that parameter collected at regular intervals over the preceding 3 years are all at less than 60% of the parametric value;
(b)the results of a risk assessment are considered, and that risk assessment indicates that no factor can be reasonably anticipated to be likely to cause deterioration of the quality of the water for human consumption;
(c)data collected in the course of discharging its monitoring obligations under this Part are taken into account; and
(d)at least one sample is taken per year.
(2) A local authority may set a higher frequency for any parameter if it considers it appropriate taking into account the findings of any risk assessment.