2018 Seattle Plumbing Code 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 City of Seattle. Consists of Washington State and Seattle Amendments integrated into the 2018 Uniform Plumbing Code. Includes the new Water Demand Calculator for estimating water supply demand and pipe sizing.