Section 611.744  Filtration Sampling Requirements

a)         Monitoring Requirements for Systems Using Filtration Treatment.  In addition to monitoring required by Sections 611.531 and 611.533, a PWS subject to the requirements of this Subpart R that provides conventional filtration treatment or direct filtration must conduct continuous monitoring of turbidity for each individual filter using an approved method in Section 611.531(a) and must calibrate turbidimeters using the procedure specified by the manufacturer.  Systems must record the results of individual filter monitoring every 15 minutes.

b)         If there is a failure in the continuous turbidity monitoring equipment, the system must conduct grab sampling every four hours in lieu of continuous monitoring, until the turbidimeter is back online.  A system must repair the equipment within a maximum of five working days after failure.

BOARD NOTE:  Derived from 40 CFR 141.174.

(Source:  Amended at 44 Ill. Reg. 6996, effective April 17, 2020)