25. In this Part—
“regulation 29 requirements” means the requirements of paragraphs (2) and (4) of regulation 29;
“risk assessment”, in relation to a treatment works, means an assessment for that treatment works, to establish whether there is, or continues to be, a significant risk from cryptosporidium oocysts in water supplied from the works;
“significant risk from cryptosporidium”, in relation to water supplied from a treatment works, means a significant risk that the average number of cryptosporidium oocysts per 10 litres of water supplied from the works for regulation 4(1) purposes, if sampled and analysed in accordance with regulation 29(5) to (15), would at any time be one or more; and
“surface water” does not include water from a spring.