Plumbing Glossary
Plain-language definitions for the terms you'll see across our guides — no jargon.
- Anode Rod
- A sacrificial metal rod inside a tank water heater that corrodes in place of the tank to extend its life. It depletes faster in hard-water areas like the East Bay. Learn more →
- Authority Having Jurisdiction (AHJ)
- The local agency — usually a city or county building department — that adopts and enforces plumbing code and issues permits. Rules can vary city to city. Learn more →
- Backflow
- Unwanted reverse flow that can let contaminated water enter the clean supply. Backflow-prevention devices guard against it and may require periodic testing. Learn more →
- California Plumbing Code (CPC)
- The statewide plumbing code (based on the Uniform Plumbing Code) that local jurisdictions enforce, sometimes with local amendments. Learn more →
- Camera (Video) Inspection
- Feeding a waterproof camera into a drain or sewer line to pinpoint clogs, root intrusion, or breaks without digging. Learn more →
- Descaling (Flushing)
- Periodically clearing mineral scale from a water heater — especially a tankless unit — to protect efficiency and warranty. Needed more often in hard water. Learn more →
- Drain Snake (Auger)
- A flexible cable fed into a drain to break through or pull out a clog. Fast and inexpensive for simple stoppages. Learn more →
- Expansion Tank
- A small tank that absorbs the pressure increase as water heats and expands. Code often requires one on a closed system with a water heater. Learn more →
- Galvanized Pipe
- Older zinc-coated steel supply pipe that corrodes and restricts flow over decades — common in mid-century Concord, Antioch, and Pittsburg homes. Learn more →
- Gas Line
- The piping that delivers natural gas to appliances. Gas work typically requires a permit and a pressure test, and should only be done by a licensed pro. Learn more →
- Grains Per Gallon (GPG)
- A measure of water hardness — the higher the GPG, the harder the water and the more scale it leaves behind. Learn more →
- Hard Water
- Water high in dissolved calcium and magnesium that leaves scale and spots and shortens appliance life. It is prevalent across East Contra Costa County. Learn more →
- Hydro-Jetting
- High-pressure water cleaning that scours the full diameter of a drain or sewer line, clearing grease, scale, and tree roots. Learn more →
- PEX
- Cross-linked polyethylene — a flexible plastic water-supply pipe that is freeze-resistant and quick to install. Learn more →
- Repipe
- Replacing some or all of a home's water-supply pipes, usually because of age, corrosion, or recurring leaks. Learn more →
- Salt-Free Conditioner
- A system that alters scale-forming minerals so they don't stick to surfaces, without removing them or adding sodium. Not the same as a softener. Learn more →
- Sediment
- Mineral deposits (mostly calcium) that settle in a water heater tank, cutting efficiency and capacity — accelerated by hard water. Learn more →
- Sewer Lateral
- The pipe carrying wastewater from your home to the public sewer main. The homeowner is typically responsible for it, and some cities require it to be certified at sale. Learn more →
- Tankless Water Heater
- A unit that heats water on demand as it flows through, rather than storing it. It offers endless hot water and a longer lifespan with regular maintenance. Learn more →
- Temperature & Pressure Relief (T&P) Valve
- A safety valve that releases water if a water heater's temperature or pressure climbs too high. Learn more →
- Title 24
- California's building energy-efficiency standards, which affect water heating and plumbing fixtures during upgrades and replacements. Learn more →
- Trenchless Sewer Repair
- Repairing or replacing a sewer line with minimal digging using pipe lining or pipe bursting — faster and less disruptive than full excavation. Learn more →
- Water Softener
- A system that removes hardness minerals through ion exchange, protecting pipes, fixtures, and appliances from scale. Learn more →