Oregon Administrative Rules
Chapter 340 - DEPARTMENT OF ENVIRONMENTAL QUALITY
Division 73 - CONSTRUCTION STANDARDS
Section 340-073-0035 - Distribution Boxes

(1) Distribution boxes must be constructed of concrete, fiberglass, or other materials acceptable to the department.

(2) Distribution boxes must be constructed of durable, watertight materials resistant to deterioration and be designed to accommodate watertight connections for the effluent sewer and header pipes. The top, walls, and bottom of concrete distribution boxes must be at least 1-1/2 inches thick. All distribution boxes must be able to support an earth load of at least 200 pounds per square foot.

(3) The invert elevation of all outlets must be the same and must be at least 2 inches below the inlet invert.

(4) Each distribution box must be provided with a sump extending at least 2 inches below the invert of the outlets unless otherwise authorized by the department.

(5) Distribution box covers must be marked with the manufacturer's full business name or number assigned by the department.

(6) Each manufacturer must provide the department with complete, detailed plans and specifications of the distribution box and must certify, in writing, that distribution boxes manufactured for use in onsite sewage systems in Oregon will comply with all requirements of this rule. Plans and specifications must be prepared under the supervision of and designed by a professional engineer licensed in accordance with ORS chapter 672.