07 - Drain, Waste, and Vent Pipes - DWV System Materials and Installation

Send us Fan MailUnderstand the drain, waste, and vent system that removes wastewater from homes in this detailed episode covering pipe materials, sizing, installation, and common problems. DWV systems are often less visible than water supply systems but equally critical to proper plumbing function.We start with general installation requirements: smooth interior surfaces, proper slope, and why pipes shouldn't be reduced in size in the direction of flow. You'll understand basic DWV pipe sizing principles and when inadequate pipe size might be causing drainage problems.ABS (Acrylonitrile Butadiene Styrene) pipe receives thorough coverage, including identification, proper support intervals, connection methods, and the problematic pipe manufactured between 1985-1990 by specific companies. We explain regional preferences, with ABS more popular in the West.PVC pipe is explored in depth, including the critical distinction between plumbing PVC and electrical conduit PVC. You'll learn proper primer and solvent cement application, support requirements, and why purple primer visibility is required in many jurisdictions.Cast iron pipe, the traditional DWV material, receives extensive coverage. We explain hub and spigot connections, both caulked joints with oakum and lead, and modern compression gasket systems. You'll learn to identify deterioration signs like rust cysts and top-of-pipe cracking, and understand why most cast iron is beyond its expected service life.Legacy materials receive attention, including clay sewer pipe, Orangeburg fiber pipe, and galvanized steel. For each material, we cover identification, expected service life, common failure modes, and appropriate recommendations.The episode concludes with modern sewer pipe repair methods: bursting, sliplining, and cured-in-place pipe, helping you understand alternatives to complete replacement when discussing options with clients.Intro This episode is brought to you by GetSync.pro This episode is hosted by Charlie Bellefontaine of Chicagoland Home InspectorsFor complete training with visual materials, practice exams, and certification support, visit nhiexamprep.com© 2025 National Home Inspector Exam Prep Podcast. All rights reserved.