The District Sanitary Sewerage System Design Standards (PDF) (includes Standard Specifications and Standard Drawings) establish uniform policies and procedures for the design and construction of the District's wastewater collection and transport system. They are not intended to substitute for engineering knowledge, judgment, or experience. Sound judgment must be exercised in the application of these standards to specific circumstances. The contents do not preclude the use of different methods when special or emergency conditions warrant and when proper authorization is obtained.