Home plumbing systems are composed of four primary subsystems that need to work jointly, though there are some differences based on whether the home connects to a municipal system for water or sewage. Drains take wastewater from the house and send it into a municipal drain or a septic tank. The wastewater treatment differs between the two, but their primary function is the same. Both drain systems have cleanouts that give residential plumbers access to the drain systems to fix plugged drains.
Home plumbing systems also have vents, which connect the drains to air through a vent or pipe in the roof.
The vents provide air pressure to help push wastewater through the system. Residential plumbing systems also provide fresh or potable for consumption in the home. Municipal systems use pumps or water towers to provide pressure that pushes water into the homes, while homes not connected to municipal systems receive water from wells.
The final component of the residential plumbing system that is sometimes not considered part of the plumbing system is wastewater management. Rain and melting snow that fall on the roof and some portions of the yard must be drained effectively and moved away from the home foundation. Most municipal systems now separate their waste and rainwater draining processes to better handle peak periods of water flow.