(1) No interties shall be used and/or constructed as a public water supply without department approval.

(2) Interties shall not be eligible for submittal exceptions pursuant to WAC 246-290-125.

(3) Prior to department approval, purveyors proposing nonemergency interties shall ensure that the intertie is addressed:

(a) In an approved coordinated water system plan, water system plan, water system plan update, water system plan amendment, or small water system management program including:

(i) Location of the proposed intertie;

(ii) Date it is proposed to be utilized;

(iii) The purpose, physical capacity, service area, and proposed usage of the intertie;

(iv) Copy of the intertie agreement between purveyors;

(v) Description of how the intertie:

(A) Improves overall system reliability;

(B) Enhances the manageability of the system;

(C) Provides opportunities for conjunctive use; or

(D) Delays or avoids the need to develop new water sources;

(vi) Identification of any potential public health or safety concerns;

(vii) Discussion of any water quality and treatment issues;

(viii) Demonstration of the source capacity and hydraulic capacity of the supplying and receiving systems at the designed flow rate through the intertie;

(ix) Water right self-assessment;

(x) Identification of alternative sources that will be utilized when the intertie agreement expires if the water is not being provided in perpetuity; and

(xi) Identification and comparison of alternatives if any.

(b) In construction documents under WAC 246-290-120 including:

(i) Demonstration of the installation of a source meter to measure water exchanged; and

(ii) Water right self-assessment, if not previously provided to the department. When RCW 90.03.383 requires a water right or water right change to be issued by the department of ecology, construction work on the intertie shall not begin, until the department of ecology issues the required water right document.

(4) Emergency use interties are interconnections between public water systems permitting the temporary exchange or delivery of water between those systems only in cases of emergency that result in permanent supplies being unavailable for use. Prior to department approval, purveyors proposing emergency use interties shall ensure that the emergency intertie is addressed:

(a) In an approved coordinated water system plan, water system plan, water system plan update, water system plan amendment, or small water system management program including:

(i) Description of the intended use of the emergency intertie;

(ii) Location of the proposed intertie;

(iii) Date the intertie is intended to be operational;

(iv) Copy of the intertie agreement between purveyors detailing the conditions and limitations of the intertie; and

(v) Hydraulic analysis conducted to identify the impacts upon each water system.

(b) In a project report under WAC 246-290-110 or in a construction document under WAC 246-290-120.

(5) Purveyors proposing interties shall apply to the department of ecology for water right changes as provided in RCW 90.03.383. Except as provided in RCW 90.03.383(7) and 90.03.390, no interties may be constructed without department of ecology action on the proposed change.

(6) The purveyor may be required to have emergency interties approved as nonemergency interties where the interties are used frequently or on a long-term basis. If the department makes a determination, the intertie will require approval in accordance with subsection (3) of this section.

(7) Intertie agreements between purveyors shall include:

(a) Identification of specific time periods in which water will be provided;

(b) Identification of the volume of water available for use, including any seasonal or other restrictions; and

(c) Identification of how water use efficiency programs, data collection, water demand forecasting, and other operational matters will be coordinated.