The Water Supply (Water Quality) Regulations (Northern Ireland) 2017

Disinfection and other treatment arrangements N.I.

29.—(1) Unless the conditions in paragraph (4) are satisfied, before supplying water for regulation 5(1) purposes, a water undertaker must—

(a) disinfect the water; and

(b) where necessary, subject the water to sufficient preliminary treatment to prepare it for disinfection.

(2) A water undertaker must—

(a) design, operate and maintain the disinfection process so as to keep the presence of disinfection by-products as low as possible without compromising the effectiveness of the disinfection; and

(b) verify the performance of the disinfection process.

(3) Paragraph (4) applies when any property, organism, or substance is present in a water source at a level that may constitute a potential risk to human health.

(4) Unless the conditions in paragraph (5) are satisfied, before supplying water for regulation 5(1) purposes using water from any source, a water undertaker must design and continuously operate an adequate treatment process for water from the source.

(5) The conditions are that a water undertaker—

(a) must supply water from the treatment works as a matter of urgency in order to prevent an unexpected interruption in piped supply to consumers; and

(b) before a supply is made, has taken all necessary steps to inform consumers that the water is not disinfected or adequately treated.

(6) For the purposes of this regulation—

(a) “adequate treatment process” means a process of blending or purification treatment which—

(i) removes, or

(ii) renders harmless the value or concentration of,

any property of water, organism or substance in water, so that supplies do not constitute a potential risk to human health;

(b) “sufficient preliminary treatment” means the treatment necessary—

(i) to remove, or to reduce the value or concentration of, any property or substance which would interfere with disinfection; and

(ii) to reduce turbidity to less than one Nephelometric Turbidity Unit (NTU); and

(c) water is supplied for regulation 5(1) purposes when it leaves a treatment works.

(7) Article 30 of the 2006 Order applies to the enforcement by the Department of the duties under this regulation in the same way as it applies to the enforcement by the enforcement authority of the duties to which that Article applies.