The Main Types of Plumbing Pipes
There are several different types of pipes used in home plumbing systems, each suited to different purposes. Let’s take a look at the most common types:
- PVC (polyvinyl chloride) pipes – PVC is one of the most widely used pipe materials for water supply lines. It is durable, flexible, and resistant to corrosion and freezing. PVC comes in different diameters and pressure ratings for various applications.
- Copper pipes – Copper piping is a popular choice for water supply lines and for drain, waste, and vent (DWV) systems. It has excellent durability and conducts heat well for hot water distribution. Copper is more expensive than PVC but lasts longer.
- PEX (cross-linked polyethylene) pipes – PEX has grown in popularity as a flexible, affordable alternative to copper for water supply lines. It can expand and contract without bursting or cracking. PEX is available in several colors to identify water lines.
- Cast iron pipes – Durable cast iron pipes were commonly used in the past for DWV systems and some water supply lines. They are heavy-duty but can rust and corrode over time.
- Galvanized steel pipes – Galvanized steel was widely used historically but is no longer code-compliant due to corrosion concerns. It may still be found in older homes.
Water Supply Piping
The main water supply line typically enters the home underground and connects to the home’s plumbing system near the water meter. From there, branch lines distribute cold and hot water throughout the house.
- Cold water lines transport untreated water from the main line to fixtures like sinks, toilets, and outdoor spigots. These are usually copper, PEX, or PVC.
- Hot water lines carry heated water from the water heater to fixtures. Copper is most common for its heat conductivity. PEX can also be used if rated for hot water.
- Manifold piping may be used to simplify the distribution of hot and cold water to multiple fixtures from a central location, rather than separate branch lines to each.
- Shut-off valves installed on supply lines allow sections to be turned off for repairs without disrupting other fixtures. The main shut-off controls water to the entire home.
Drain, Waste, Vent Piping
DWV piping removes waste water and gases from plumbing fixtures while preventing blockages. It consists of:
- Drain lines transport waste water from sinks, tubs, showers and other fixtures to the main drain stack. PVC and cast iron are typical materials.
- Vent lines allow sewer gases to safely exit the home’s plumbing system. These vertical pipes connect to drain lines and extend above the roof.
- Traps are U-shaped sections of pipe under sinks, tubs, etc. that hold standing water to block sewer gases while allowing waste to pass through.
- The main drain stack acts as the central waste removal column that all horizontal drain lines tie into before exiting the home.
- Cleanouts are removable plugs in drain lines that allow blockages to be cleared from accessible locations without dismantling pipes.
Proper slope is critical for unimpeded waste flow in drain lines. Vents allow pressure equalization. Together this keeps traps sealed while efficiently evacuating waste.
Understanding Your Home’s Plumbing System
Being familiar with the different pipe types used for water supply and waste removal can help homeowners identify issues and make repairs. For example, knowing the cold water lines are usually copper or PEX aids in locating leaks. Understanding how drain lines tie into the main soil stack helps snake clogs. With some basic plumbing knowledge, you can better care for your home’s lifeline – the plumbing system! Let me know if you have any other plumbing questions.
