The Urban Waste Water Treatment Regulations (Northern Ireland) 1995

2.—(a) Flow-proportioned or time-based 24-hour samples shall be collected at the same well-defined point in the outlet and if necessary in the inlet of the treatment plant in order to monitor compliance with the requirements for discharged waste water laid down in these Regulations.

(b)Good international laboratory practices aiming at minimising the degradation of samples between collection and analysis shall be applied.