Section: WAC 246-290-640(4).
Issuing Entity: Alan Rowe, Operations Manager, Division of Drinking Water.
Description of Subject Matter: Once a potential ground water under the direct influence of surface water (GWI) source is determined or presumed to be in "hydraulic connection" to a surface water (SW), the purveyor is required to provide disinfection treatment, unless the purveyor chooses to modify the source to mitigate SW influence. During this period of unknown risk to public health, the regulations do not specify a schedule to initiate disinfection. This statement provides direction to staff and stakeholders regarding how long disinfection may be deferred, and what requirements and recommendations apply while awaiting source modifications or installation of treatment facilities.
Division Contact: Ethan Moseng, Division of Drinking Water, P.O. Box 47829, Olympia, WA 98504-7829, (360) 236-3562.
Effective Date: March 30, 2001.