Grandparent certificates are site specific, nontransferable and can only be issued to an existing operator of an existing system according to IDAPA 58.01.08.555.01. The term "an existing or a single system" is not defined in said rule. The lack of specific definition is resulting in water system operators erroneously applying for grandparent certification. The lack of specificity is also creating a lack of consistency for DEQ staff and the Idaho Water/Wastewater Operator Certification Board when responding to inquiries.

To interpret the IDAPA 58.01.08.555.01 wording which says, "a system" or "a single drinking water system" in order to determine eligibility for a drinking water grandparent certificate.

A single system or an existing system is determined by the individual public water system (PWS) identification number rather than ownership, entity, mailing address, physical location, point of discharge, or water source. There are four advantages to using the existing PWS number as the defining component. First, PWS numbers have already been established for all existing public water systems in the state drinking water database system. Second, using the existing PWS number will prevent unnecessary duplication of effort and will expedite record keeping and accounting by eliminating confusion and mismanagement of additional files. Third, using the individual PWS number holds the owner of the water system responsible for compliance of an individual system without adverse impacts to any other water system. For example, if one entity owns System A (PWS #123) and System B (PWS #456), and were considered to be one system because of the single ownership, then the consequences of any violations from System A must also apply to System B. This means if System A were required to boil their water, then a "Boil Water" order would also be in effect for System B. Finally, the fourth advantage to using the PWS number involves protecting innocent homeowners when sanitary restrictions must be imposed or reimposed.