Building Drainage & Stormwater Management Quick Reference Guide

Building drainage encompasses the controlled removal of wastewater (sanitary and greywater) and stormwater from roofs, paved surfaces, and landscaped areas via piping systems, channels, and retention/detention features. Stormwater management specifically addresses the hydrologic and hydraulic challenges posed by impervious surfaces—such as increased runoff volume, peak flow rates, and pollutant loading—by applying principles of water balance, time-of-concentration analysis, and low-impact development (LID). Core design standards draw from national and local codes (e.g., IPC, UPC, ASCE 24, EPA SWMM guidance) and integrate climate-resilient considerations like intensified rainfall intensities due to climate change. Practical implementation requires coordinated integration across disciplines: civil engineering (hydraulic modeling, pipe sizing), landscape architecture (bioswales, rain gardens), and building services (roof scuppers, downspout routing). Performance verification often relies on tools such as TR-55, Rational Method calculations, and continuous simulation models (e.g., SWMM) to validate compliance with municipal MS4 permits, watershed-level TMDLs, and green building certifications (e.g., LEED v4.1 SSc6, Green Globes Stormwater Management).