Regulation 12 Sampling: further provisions

As soon as a water undertaker has reasonable grounds (such as the findings of a risk assessment) for believing that any element, organism or substance, other than residual disinfectant or a parameter (whether alone or in combination with a parameter or any other element, organism or substance) may cause the supply within any of its water supply zones to be a supply which does not satisfy—

it must take, or cause to be taken, sufficient samples from water within that zone (whether from a service reservoir, a treatment works or otherwise) in respect of that element, organism or substance, in order to establish whether that water is wholesome.