1. (1) The requirements of Part 6 of this chapter apply to water systems that:

   1. (a) Use surface sources or groundwater sources under the direct influence of surface water (GWI); or
   2. (b) Purchase surface or GWI water from an approved public water system or other entity acceptable to the department.

2. (2) The requirements of Part 6 of this chapter do not apply to water systems that use unfiltered surface or GWI sources as emergency sources, provided the source is physically disconnected from the system at all times until it is needed, and the purveyor meets the following conditions:

   1. (a) Has a department-approved emergency response plan; and
   2. (b) Provides disinfection treatment that meets the requirements under WAC 246-290-662 (2)(d).
3. (3) The requirements of WAC 246-290-640 apply to Group A systems that use sources potentially under the influence of surface water as determined by the department.

[Statutory Authority: RCW 43.20.050 and 70.119A.080. WSR 10-20-068, § 246-290-620, filed 9/29/10, effective 11/1/10. Statutory Authority: RCW 43.02.050 [43.20.050]. WSR 99-07-021, § 246-290-620, filed 3/9/99, effective 4/9/99. Statutory Authority: RCW 43.20.050. WSR 93-08-011 (Order 352B), § 246-290-620, filed 3/25/93, effective 4/25/93.]