Plumbing quotes and inspection reports are full of terms that most homeowners never hear until something goes wrong. This glossary explains the words you are most likely to run into when you are looking at a repipe, a leak repair, or a water heater replacement, in plain language. Use it to read an estimate with confidence and to ask better questions before you book a service.

Jump to a letter: A · B · C · D · E · F · G · H · L · M · P · R · S · T · W

A

Access panel. A removable cover cut into a wall or ceiling that gives a plumber access to pipes, valves, or a tub drain without larger demolition.

Anode rod. A metal rod inside a tank water heater that corrodes on purpose so the steel tank does not. Checking and replacing it is one of the best ways to extend a tank’s life.

B

Backflow preventer. A device that stops water from flowing backward into the clean supply, which protects drinking water from contamination.

Ball valve. A shutoff valve with a quarter-turn handle. It is more reliable over time than older gate valves, which can seize or leak.

Bonded and insured. A bonded contractor carries a surety bond that protects the customer if the contractor fails to complete a job or follow the law. Insurance covers damage or injury during the work. Always confirm both.

Burst pipe. A pipe that has split open, often from corrosion, high pressure, or freezing, and releases a large amount of water quickly. Shut off the main water valve and call a plumber right away. See our pipe burst repair service.

C

C-36 license. The California contractor license classification for plumbing contractors, issued by the Contractors State License Board (CSLB). Repipe Home Hero holds C-36 License #1075463.

Cast iron pipe. A heavy, durable pipe used mostly for drain and sewer lines in older homes. Over decades it can corrode, crack, or clog from the inside.

Cleanout. A capped opening in a drain line that gives a plumber access to clear a blockage or inspect the line.

Code compliance. Work that meets the current plumbing code and passes inspection, including pipe sizing, materials, venting, and safe installation.

Copper pipe. A long-lasting metal supply pipe that has been used in homes for decades. Common residential types are Type M (thinner wall), Type L (thicker wall, the standard for many repipes), and Type K (thickest). See our copper repiping page.

Corrosion. The gradual breakdown of metal pipe from chemical reactions with water, minerals, or other metals. It causes pinhole leaks, discolored water, and reduced flow.

CPVC. Chlorinated polyvinyl chloride, a rigid plastic pipe used for hot and cold water supply. It can become brittle with age.

CSLB. The California Contractors State License Board. You can look up any contractor’s license class and status on its website before you hire.

D

Dielectric union. A fitting that joins two different metals, such as copper and galvanized steel, and helps limit the corrosion that happens when they touch.

Drain-waste-vent (DWV). The system of pipes that carries wastewater out of the house and vents sewer gases outside. It is separate from the pressurized supply lines a repipe replaces.

Drywall repair and texture matching. Patching the openings made in walls to reach pipes, then matching the existing wall texture so the repair is hard to see. Repipe Home Hero includes it in every repipe.

E

Emergency shutoff. The valve that stops water flow into the house, often at the main line near the street or on an outside wall. Everyone in the home should know where it is.

Epoxy pipelining. A method that coats the inside of existing pipes with an epoxy lining instead of replacing them. It depends on pipe condition and access, and it is different from a full repipe.

Expansion tank. A small tank that absorbs the extra pressure created when water heats up in a closed plumbing system, which protects pipes and the water heater.

F

First-hour rating. The amount of hot water a tank water heater can deliver in one hour starting with a full tank. It is printed on the unit’s EnergyGuide label and often matters more than tank size. See our guide on water heater size for a family of 4.

Flexible connector. A braided hose that connects a fixture or appliance to a rigid supply pipe. Connectors wear out over time and should be replaced when they show wear.

Flow rate. How much water moves through a pipe or fixture, usually measured in gallons per minute (GPM).

G

Galvanized steel pipe. Steel pipe coated in zinc, common in homes built before the 1960s. The coating wears away and the pipe rusts from the inside, which restricts flow and discolors water.

Gas line. The pipe that carries natural gas to appliances such as a water heater, furnace, or range. A tankless gas water heater often needs a larger gas line than a tank does.

GPM. Gallons per minute, the standard measure of flow rate for fixtures and tankless water heaters.

H

Hard water. Water with a high mineral content, mostly calcium and magnesium. It leaves scale in pipes, fixtures, and water heaters and is common across San Diego County.

Hose bib. An outdoor faucet, also called a spigot. A leaking hose bib can waste water and damage the wall behind it.

Hybrid water heater. A water heater that uses a heat pump to move heat into the tank, with backup heating elements, to cut energy use. It is also called a heat pump water heater.

L

Leak detection. Locating a hidden leak using tools such as acoustic listening devices, pressure tests, and thermal or moisture imaging, so a plumber can open as little wall or floor as possible.

Low water pressure. Weak flow at faucets and showers. Causes include a failing pressure regulator, a partly closed valve, sediment, or corroded supply pipes. It is a common reason homeowners consider a repipe.

M

Main water line. The pipe that brings water from the city meter or well into your home. See our main water line repair service.

Manifold. A central distribution point where individual pipes run to each fixture. Many PEX systems use a manifold so each fixture has its own supply line.

P

Permit. Official approval from the local building department for plumbing work. Most jurisdictions require one for a repipe, and the work is then inspected.

PEX. Cross-linked polyethylene, a flexible plastic pipe used for water supply. It resists corrosion and scale and installs with fewer joints. See our PEX repiping page.

Pinhole leak. A tiny leak caused by corrosion eating through a pipe wall, most often in copper. A single pinhole is often a sign of more to come.

Pipe reroute. Moving a pipe to a new path, usually to avoid a damaged section, reach a remodeled space, or bypass a slab. See our pipe reroute service.

Polybutylene. A gray plastic pipe used in many homes from the late 1970s through the mid-1990s. It is known for failing at fittings, and many homeowners replace it.

Pressure regulating valve (PRV). A valve that lowers the incoming water pressure to a safe level for the home, typically around 50 to 60 psi. It is also called a pressure reducing valve. See our pressure regulator installation service.

P-trap. The curved section of drain pipe under a sink that holds water to block sewer gas from entering the house.

psi. Pounds per square inch, the unit used to measure water pressure. Pressure above about 80 psi can stress pipes and fixtures.

R

Repipe. Replacing a home’s old supply pipes with new ones, usually in copper or PEX. A whole house repipe replaces most or all of the supply lines. See our whole house repipe service and our guide on why a home needs a repipe.

Repipe vs. spot repair. A spot repair fixes one leak. A repipe replaces the aging system. If leaks keep appearing in different places, repairs usually become more expensive than replacement.

S

Sediment. Mineral particles and debris that settle at the bottom of a water heater tank or collect in fixtures. Flushing the tank each year removes it.

Slab leak. A leak in a pipe under or inside a concrete foundation slab. Warning signs include unexplained water bills, warm spots on the floor, and the sound of running water. See our water pipe leak repair service.

Standby loss. Heat that escapes from a tank water heater while it sits idle, which is energy you pay for and never use.

Supply line. Any pipe that carries pressurized, clean water into the home and to fixtures, as opposed to a drain line that carries it away.

T

Tankless water heater. A water heater that heats water on demand as it flows, with no storage tank. It offers endless hot water within its flow limit. See our tankless water heater installation service and our guide on tankless pros and cons.

Temperature and pressure relief (TPR) valve. A safety valve on a water heater that opens to release water if temperature or pressure gets too high.

Texture matching. See drywall repair and texture matching.

W

Water hammer. A loud banging noise in the pipes when a valve closes suddenly and stops moving water abruptly. It can loosen pipes and fittings over time.

Water heater. An appliance that heats and stores, or heats on demand, the hot water for your home. See our water heater installation service.

Water meter. The device that measures how much water enters your home. If it keeps moving when every fixture is off, you may have a leak.

Whole-house filtration. A filter system installed where water enters the home that treats all the water, not just a single tap. See our whole house water filter installation service.

Need Help With a Term on Your Estimate?

If a quote or inspection report uses a word that is not on this list, ask your plumber to explain it before you approve any work. A good contractor will be happy to walk you through it.

Repipe Home Hero offers free, no-obligation estimates for San Diego County homeowners. Call (619) 386-0375 or request an estimate online.