The 2021 edition of the Washington State Specialty Code
represents a custom plumbing code published for the state. This code is based
on the 2021 Uniform Plumbing Code (UPC) and updated with the recent Washington
State Building Council amendments. Provisions contained in the Washington
Plumbing Code provide minimum standards to safeguard life or limb, health,
property, and public welfare. It also protects against hazards that may arise
from the use of plumbing piping and systems by regulating and controlling the
design, construction, installation, quality of materials, location, and
operation of plumbing piping systems within the State of Washington.