Plumbing Glossary
Clear definitions of plumbing terms every homeowner should know before calling a plumber.
A
- Auger
- A flexible snake-like tool used to clear drain clogs. A drain auger (or plumber's snake) is inserted into a pipe to break up or retrieve blockages.
- Anode Rod
- A sacrificial metal rod inside a water heater tank that attracts corrosive elements to protect the tank from rust. Should be replaced every 3–5 years to extend water heater life.
B
- Backflow
- The unwanted reversal of water flow in a plumbing system, which can contaminate the clean water supply. Backflow preventers are devices installed to stop this.
- Ballcock
- The fill valve inside a toilet tank that controls the flow of water into the tank after flushing. When it fails, it can cause constant running water.
C
- Copper Pipe
- A traditional plumbing material known for its durability and resistance to bacteria. Copper pipe is more expensive than PEX or PVC but has a long service life.
- CPVC
- Chlorinated Polyvinyl Chloride — a plastic pipe used for hot and cold water supply lines. More temperature-resistant than standard PVC but less flexible than PEX.
D
- Drip Leg
- A short, capped section of pipe on a gas line that collects condensation and debris before it reaches the appliance. Required by code for most gas appliances.
E
- Expansion Tank
- A small tank connected to a water heater that absorbs the pressure increase caused by thermal expansion when water heats up, preventing damage to the plumbing system.
F
- Flange
- A flat fitting that connects a pipe to another component. The toilet flange (closet flange) connects the toilet to the drain pipe and the floor.
G
- Galvanized Pipe
- Steel pipe coated with zinc to prevent corrosion, commonly used in homes built before the 1960s. Galvanized pipes corrode from the inside over time, reducing flow and causing leaks.
H
- Hydro Jetting
- A drain cleaning method that uses high-pressure water (up to 4,000 PSI) to blast away grease, mineral buildup, and debris from pipe walls.
P
- P-Trap
- A U-shaped pipe section under sinks and drains that holds water to prevent sewer gases from entering your home. Named for its P-like shape when viewed from the side.
- PEX Pipe
- Cross-linked polyethylene pipe used in modern plumbing installations. PEX is flexible, resistant to freezing, and easier to install than rigid copper pipe.
- PRV
- Pressure Reducing Valve — a device installed on the main water line that reduces city water pressure to a safe level for household plumbing systems.
S
- Shutoff Valve
- A valve that controls water flow to a specific fixture or the entire home. Knowing the location of your shutoff valves is critical for managing plumbing emergencies.
- Sewer Lateral
- The underground pipe that connects your home's plumbing to the municipal sewer system. Homeowners are typically responsible for maintaining the sewer lateral up to the property line.
T
- Trenchless Repair
- Sewer and pipe repair methods that do not require extensive excavation. Includes pipe lining (CIPP) and pipe bursting. More expensive per foot but less disruptive to landscaping.
W
- Water Hammer
- A banging or knocking sound in pipes caused by sudden changes in water pressure, usually when a faucet or valve is quickly closed. Can damage pipes over time.
- Water Pressure
- The force at which water flows through your pipes, measured in PSI (pounds per square inch). Ideal home water pressure is 40–60 PSI. Above 80 PSI can damage pipes and appliances.
- Wax Ring
- A ring-shaped gasket made of wax that creates a watertight seal between the base of a toilet and the floor drain (flange). Must be replaced when a toilet is removed.