Wholesomeness
4.—(1) Subject to paragraphs (4) and (5), water supplied to premises that is intended for human consumption including—
(a)for such domestic purposes as consist in or include, cooking, drinking, food preparation or washing, or
(b)for food production purposes,
is to be regarded as wholesome for the purposes of Chapter III, as it applies to the supply of water for those purposes, if the requirements of paragraph (2) are satisfied.
(2) The requirements of this paragraph are—
(a)that the water does not contain—
(i)any micro-organism (other than a parameter listed in Schedule 1) or parasite, or
(ii)any substance (other than a parameter listed in Schedule 1),
at a concentration or value which would constitute a potential danger to human health;
(b)that the water does not contain any substance (whether or not a parameter) at a concentration or value which, in conjunction with any other substance it contains (whether or not a parameter) would constitute a potential danger to human health;
(c)that the water does not contain concentrations or values of the parameters listed in Tables A and B in Schedule 1 in excess of or, as the case may be, less than, the prescribed concentrations or values; and
(d)that the water satisfies the formula “[nitrate]/50 + [nitrite]/3 < 1”, where the square brackets signify the concentrations in mg/l for nitrate (NO3) and nitrite (NO2).
(3) The point at which the requirements of paragraph (2), in so far as they relate to the parameters set out in Part 1 of Table A and in Table B in Schedule 1 are to be complied with is—
(a)in the case of water supplied from a tanker, the point at which the water emerges from the tanker;
(b)in the case of water supplied in bottles or containers, the point at which the water first emerges from any bottle or container collected from a local distribution point;
(c)in the case of water used in a food production undertaking, the point at which it is used in the undertaking; and
(d)in any other case, the consumer’s tap.
(4) Water supplied for regulation 4(1) purposes will not be regarded as wholesome for the purposes of Chapter III if, on transfer from a treatment works for supply for those purposes—
(a)it contains a concentration of the coliform bacteria or E coli parameter (items 1 and 2 in Part 2 of Table A in Schedule 1) in excess of the prescribed concentrations; or
(b)it contains a concentration of nitrite in excess of 0.1 mg NO2/l.
(5) Subject to paragraph (6), water supplied for regulation 4(1) purposes will not be regarded as wholesome for the purposes of Chapter III if, on transfer from a service reservoir for supply for those purposes, it contains a concentration of the coliform bacteria or E coli parameter in excess of the prescribed concentrations.
(6) Water transferred from a service reservoir for supply for regulation 4(1) purposes is to be regarded as unwholesome if more than 5% of samples taken in a year exceed the prescribed concentration for the coliform bacteria parameter.