The requirements of 40 C.F.R. 141.74(c), adopted by reference in 18 AAC 80.010(a), and of 18 AAC 80.655 apply to a community water system, non-transient non-community water system, or transient non-community water system that uses a surface water source or a GWUDISW source and that provides filtration treatment. In addition, under 40 C.F.R. 141.74(c)(1), the department will allow the system to

1. (1) substitute continuous turbidity monitoring for grab sample monitoring if the operator validates the continuous measurement for accuracy on a regular basis using a method approved under 18 AAC 80.655(c);

2. (2) reduce turbidity sampling frequency to once each day, for the systems described in 40 C.F.R. 141.74(c)(1), if the department finds that less frequent monitoring is sufficient to indicate effective filtration performance for the system, and if the owner

   1. (A) submits a written request to the department, including turbidity monitoring data for the previous 12 months; and
   2. (B) has continuously met, during those 12 months, the applicable turbidity requirements of 40 C.F.R. 141.73(b) and (c), adopted by reference in 18 AAC 80.010(a).

(Eff. 10/1/99, Register 151; am 11/9/2006, Register 180; am 4/24/2009, Register 190)

Authority: AS 46.03.020, AS 46.03.050, AS 46.03.710, AS 46.03.720