What is a clean out? A plumbing cleanout provides a convenient place to access a properties drain pipes to clear clogs and debris. You can remove a cap on the cleanout to supply the needed access. The plumbing codes of most localities require the installation of cleanouts during the plumbing rough-in during building construction. As an inspector I always try to find a clean-out. Most townhomes and condos you will not find them. However, a Single family home should have a clean out. If I cant find one, a plumber should try to locate and install one. Any house built prior to 1990 I generally recommend a scope of the clean out – a plumber puts a camera down the access point to check the main waste line.