The generator and distributor must maintain a chlorine residual as follows:

1. (1) Chlorine residual in the distribution system. A minimum chlorine residual of ≥0.2 mg/L free chlorine or ≥0.5 mg/L total chlorine is required in pipeline distribution systems conveying the reclaimed water from the facility to the point of use to prevent biological growth, prevent deterioration of reclaimed water quality, and to protect public health.

   The lead agency may waive or modify the requirements for maintaining a chlorine residual during storage or conveyance to the point of use, if the generator demonstrates a benefit from reducing or eliminating the chlorine residual. When ecology is lead agency, it must notify health of any such proposed or requested waiver or permit modification.

2. (2) Chlorine residual for use areas. A chlorine residual is not required in reclaimed water impoundments, storage ponds, and storage tanks at the point of use, or for conveyance along natural streams, lakes, surface waters, or groundwaters of the state.

[Statutory Authority: RCW 90.46.015. WSR 18-03-166 (Order 06-12), § 173-219-370, filed 1/23/18, effective 2/23/18.]