Washington Administrative Code
Title 246 - Health, Department of
SEWER SYSTEMS
Chapter 246-272B - Large on-site sewage system regulations
Part 6 - DESIGN AND TECHNICAL STANDARDS
Subpart A - General Requirements
Section 246-272B-06500 - Collection, conveyance, and other piping appurtenances

(1) Collection and conveyance systems and their sewer pipes, manholes, air release valves, lift stations, and other appurtenances must be designed and constructed to prevent contamination of drinking water, and protect ground and surface water, public health, and the environment from contamination with untreated or partially treated sewage.

(2) The design and construction of LOSS piping must be consistent with good engineering practice, the department of ecology's publication "Criteria for Sewage Works Design," August 2008, and the department of ecology and department of health publication "Pipeline Separation Design and Installation Reference Guide," July 2006.

(3) LOSS piping systems must be designed to prevent infiltration and inflow of groundwater, surface water and storm water.

(4) The department may require owners of existing LOSS to conduct infiltration and inflow analysis and may require repair and replacement of piping and appurtenances to reduce infiltration and inflow.