(1) A purveyor of a Group B system shall apply for and obtain design approval under WAC 246-291-120, or approval under subsection (3) of this section before the system:

(a) Expands to serve a new service connection needing potable water; or

(b) Provides potable water for a new use of an existing service connection if a local permitting authority requires an approved public water supply as a condition of an approval of the new use.

(2) A local permitting authority may determine a Group B system constructed before January 1, 2014, without design approval under this chapter, to be adequate for existing connections if, at a minimum, the following requirements are met:

(a) The system's source(s) must meet well construction standards, under chapter 173-160 WAC;

(b) A well site inspection completed by the department, local health jurisdiction, or designee has documented that there are no sources of contamination in the SCA that could create a public health risk;

(c) The system meets water quality standards under WAC 246-291-170, Table 2; and

(d) The system is capable of maintaining a minimum 20 psi at all points throughout the distribution system during peak demand.

(3) A purveyor of a Group B system approved prior to January 1, 2014, may provide potable water to additional service connections provided that:

(a) The expanded use is consistent with the existing design approval;

(b) The expanded use does not exceed the number of approved service connections; and

(c) The purveyor complies with all locally adopted requirements.