(1) When an owner modifies a LOSS, the component or components being modified must meet the requirements of this chapter.

(2) If the LOSS cannot meet the requirements of subsection (1) of this section, the department may consider repair or replacement of a LOSS component that is located and designed to meet new construction and treatment standards to the maximum extent allowed by the site and:

(a) Protects drinking water sources and distribution systems, and shellfish growing areas;

(b) Minimizes nitrogen discharge in areas where nitrogen is identified as a contaminant of concern;

(c) Prevents the direct discharge of sewage or partially treated sewage to groundwater, surface water, or upon the surface of the ground;

(d) Meets the horizontal setbacks described in WAC 246-272B-06050 to public drinking water sources and distribution pipes;

(e) Maximizes vertical separation, and distance to any well, spring, suction line and surface water; and

(f) Meets other requirements, as directed by the department to protect public health and the environment.

(3) Component modifications that require department approval must follow the procedures outlined in WAC 246-272B-02550. Examples of modifications requiring department approval include drainfield repair or replacement; repairs or replacement that also include improvements expanding the LOSS capacity or service area; and treatment process changes.

(4) Routine LOSS repair and equipment replacement activities that do not affect capacity or treatment performance do not require department review. Examples include pump replacement or repair, with equivalent size; minor collection pipe repair or replacement; and replacement of most valves and switches.

(5) In any submittal documents, the design engineer shall identify all the contributing factors of the failure or need for repair or replacement and design the repair or replacement to mitigate those identified possible causes or contributing factors.

(6) Drainfield reserve area is not required for repairs.

(7) All LOSS component repairs or replacements, including those to drainfields, must be located on:

(a) The property served; or

(b) A repair or replacement site where the distance between the property served and the repair or replacement site has been approved by the department based on site conditions and risk to public health and the environment.

(8) If needed, the owner shall obtain easements and right of way franchises, record them on the property title, and submit copies of the recorded documents to the department.

(9) A drainfield that cannot be repaired or replaced constitutes a failure of the LOSS and the owner shall comply with WAC 246-272B-07450.

(10) If a repair or replacement is not possible or feasible, the LOSS owner shall consult the department.