Learning Center · Glossary

Drain, Sewer & Plumbing Terms, in Plain English

The 32 words you'll hear from a technician or read on an estimate, defined the way we'd explain them at your kitchen table.

B Terms starting with B

Backwater valve: A one-way valve installed on a building's sewer line that lets wastewater flow out but closes if sewage tries to flow back toward the house — typically during a municipal sewer surcharge or heavy rain. Different from a check valve on a sump discharge. Sewer line repair
Bellied pipe (sag): A section of underground pipe that has settled lower than the pipe on either side, forming a low spot where water and solids collect instead of draining. Bellies cause recurring clogs and can often be seen on a camera inspection, although standing water in the low spot can limit visibility. Sewer camera inspection

C Terms starting with C

Cabling / snaking: Clearing a drain or sewer line by feeding a rotating steel cable with a cutting head through the pipe to break up or pull back the blockage. It restores flow but does not scour the pipe walls the way hydro jetting does. Main sewer line cleaning
Camera inspection (video inspection): Running a waterproof camera on a push rod through a drain or sewer line to see its condition from the inside — roots, cracks, offsets, bellies, scale and where a blockage actually is. The recording shows what a cable or jetter cannot. Sewer camera inspection
Cast iron pipe: The heavy, gray metal drain and sewer pipe common in homes built before the 1970s. Over decades the inside surface corrodes and builds up scale, narrowing the pipe and snagging waste; it can also develop channel rot along the bottom. Cast iron pipe descaling
Check valve: A one-way valve on a sump pump's discharge pipe that stops water in the pipe from draining back into the pit when the pump shuts off. A failed check valve makes the pump short-cycle and can flood the pit faster. Sump pump repair and replacement
Cleanout: A capped fitting on a drain or sewer line that gives direct access to the pipe for cabling, jetting or a camera without removing a fixture. Main-line cleanouts are usually near the foundation, in the yard, or in the basement floor. Drain cleaning service
Curb stop (curb box): The shut-off valve on a water service line at or near the property line, reached through a small capped tube at ground level. It marks the usual boundary between the utility-owned and property-owner-owned portions of the service line. Main water line replacement

D Terms starting with D

Descaling: Mechanically removing built-up scale and corrosion from the inside of a cast iron pipe, typically with a rotating carbide chain, followed by jetting and a camera check. The goal is to restore usable inside diameter, not to fix structural defects. Cast iron pipe descaling
Directional boring (horizontal directional drilling): Installing a new underground pipe by drilling a guided bore path from one pit to another and pulling the pipe through it, so the surface between the two points is left intact. Used where a trench would cross driveways, mature landscaping or a road. Directional boring

E Terms starting with E

Ejector pump: A sealed pump that lifts wastewater from fixtures below the level of the main sewer line — a basement bathroom, for example — up to the sewer. Unlike a sump pump it handles sewage, so its basin is sealed and vented. Plumbing services

G Terms starting with G

Galvanized service line: A water service line made of steel pipe coated in zinc, common in older homes. Over time the coating fails, the pipe corrodes from the inside and flow drops; galvanized pipe downstream of a lead line can also hold lead. Many utilities require full replacement rather than repair. Galvanized water line replacement

H Terms starting with H

Hydro jetting: Cleaning a drain or sewer line with a high-pressure water hose and a specialized nozzle that cleans the line as thoroughly as possible, removing grease, sludge, scale and roots as close to the pipe wall as conditions allow. Large root masses, offsets, breaks or heavy scale can limit how close it gets. More thorough than cabling, and usually paired with a follow-up camera inspection to evaluate the pipe and the results of the cleaning. Hydro jetting service

L Terms starting with L

Lateral (sewer lateral): The underground pipe that carries wastewater from a building to the public sewer main in the street. The property owner is usually responsible for it up to the point where it connects to the main, so it is the line most sewer repairs are about. Sewer line replacement
Lead service line: A water service line made of lead pipe, found in some homes built before lead pipe was phased out. Lead can leach into standing water, which is why utilities and health agencies push for full replacement with a compliant material rather than repair. Permits & Codes: the Columbus service-line rule

M Terms starting with M

Main line (main sewer line): The largest drain pipe in a building, which every fixture drain feeds into before it leaves the house and becomes the lateral. A main-line blockage backs up the lowest fixtures first — a floor drain or basement shower. Main sewer line cleaning

O Terms starting with O

Offset joint: A place where two sections of pipe no longer line up, usually because the ground shifted or a joint separated. The lip catches waste and roots, and a bad enough offset can stop a camera or cable from passing. Sewer pipe patching

P Terms starting with P

P-trap: The U-shaped bend under a sink, tub or floor drain that holds a small amount of water to block sewer gas from coming up through the drain. A dry trap is the most common reason a room smells like sewage. Drain cleaning service
Permit (plumbing / excavation permit): Written authorization from the local building or utility authority to do regulated work — replacing a water heater, a sewer or water service line, or gas piping, for example. A permitted job is inspected before it is closed out. Permits & Codes
PEX: Cross-linked polyethylene, a flexible plastic tubing used for water supply lines inside a home. It bends around corners with fewer fittings than copper and tolerates freezing better, which is why it is the usual choice for repiping. Whole-home repiping
Pressure-reducing valve (PRV): A valve on the incoming water line that lowers high street pressure to a safe level for the home's plumbing. When a PRV fails, fixtures can hammer, drip or fail early because the pressure inside the house is too high. Plumbing services
Push-in-place patch (point repair): A short section of resin-saturated liner positioned over a single defect in a pipe — a crack, a bad joint, a small hole — and cured in place, fixing that spot without lining the whole line or digging it up. Sewer pipe patching

R Terms starting with R

Root intrusion: Tree or shrub roots growing into a sewer line through a crack or joint, drawn by the moisture inside. Roots catch waste and grow thicker each season, so cutting them restores flow but the entry point remains until the pipe is repaired. Hydro jetting service

S Terms starting with S

Sewer surcharge: When the public sewer main fills beyond its capacity — usually during heavy rain — and pressure pushes wastewater back up laterals toward the buildings connected to it. Basement backups during storms are often surcharge, not a blockage. Weather & Safety Center
Shut-off valve: Any valve that stops water flow to part of the plumbing — the small stop under a sink or toilet, or the main shut-off where the water service enters the house. Knowing where the main is turns a burst pipe from a flood into a puddle. Plumbing services
Slab leak: A leak in a water or drain line that runs beneath a home's concrete slab foundation. Signs include warm spots on the floor, an unexplained jump in the water bill, damp flooring, or the sound of running water with everything off. Slab leak repair
Sonde / locate: A small radio transmitter (the sonde) carried on a camera head, picked up above ground with a receiver to find the approximate location of the camera head and the approximate depth of the pipe. It turns a defect on the screen into a marked area in the yard. Sewer camera inspection
Spot repair: Digging down to and replacing only the damaged section of a buried sewer or water line, rather than the whole run. It fits a single localized defect; a line with problems along its length usually points to replacement or lining instead. Sewer line repair
Sump pump: A pump set in a pit at the low point of a basement or crawlspace that collects groundwater and pumps it away from the foundation. A float switch turns it on as the pit fills; a battery backup keeps it running when the power is out. Sump pump repair and replacement

T Terms starting with T

Trenchless lining (CIPP): Cured-in-place pipe: a resin-saturated felt liner inverted or pulled into an existing pipe and cured to form a new, jointless pipe inside the old one. It needs a pipe that still holds its shape and an access point, and it slightly reduces the inside diameter. Trenchless sewer repair

W Terms starting with W

Water hammer: The bang in the pipes when a valve closes quickly and moving water stops all at once. It is usually a sign of high pressure or missing arrestors, and over time it loosens fittings and stresses appliance valves. Plumbing services
Water service line: The buried pipe that carries drinking water from the public main in the street to the meter or shut-off inside a building. It is split into a utility-owned section and a property-owner section, usually at the curb stop. Main water line repair

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