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The words plumbers use, in plain English.

Curb traps, laterals, low-water cutoffs, first-hour ratings. Every term we use in our guides, what it means for your house, and where to read more.

Sewer & Water Service Lines

Sewer services →
Backwater valve
A one-way valve installed on a sewer line that lets waste flow out to the main but closes if sewage tries to flow back toward the house. Whether one fits, and what permit it needs, depends on the home and the municipality.
Belly (sagging sewer pipe)
A section of sewer pipe that has sunk and holds standing water instead of draining. Waste and paper settle in the low spot, so the line clogs repeatedly. A liner follows the sag, so a belly usually needs excavation to correct the slope.
Combined sewer
A public sewer that carries both wastewater and stormwater in the same pipe, as in much of Philadelphia. In heavy rain it can fill up, which is one reason some basements back up during storms.
Curb stop
A shutoff valve on the water service line, usually near the curb or property line under a small metal cover, that the utility or a plumber uses to turn off water to the whole property.
Curb trap
A U-shaped trap on the sewer lateral, often near the property line, that holds water to block sewer gas. Many older Philadelphia homes have one. Because it is a low point with a bend, it is a common place for clogs and breaks.
Fresh-air inlet
A vent pipe, often capped with a small grate near the front of a house, that lets air into the drain system on the house side of a trap. A blocked or broken inlet can cause slow drains, gurgling, or sewer odor.
Lead service line
A water service line made of lead, found in some older homes. Lead can get into drinking water as the pipe ages. Utilities, including PWD, run lead service line programs; check current programs and eligibility with your water utility.
Notice of Defect (PWD)
A notice from the Philadelphia Water Department telling a property owner that a defect in their water or sewer service needs to be repaired. The notice lists what was found and a deadline; confirm the current requirements with PWD.
Open excavation
The traditional way to replace a sewer or water line: dig a trench along the pipe, remove it, lay new pipe at the correct slope, and backfill and restore the surface. It is the answer when a pipe has collapsed or needs a new slope.
Pipe bursting
A trenchless method that pulls a bursting head through the old pipe, breaking it outward into the soil while a new pipe is drawn in behind it. It needs a pit at each end and a fairly straight run.
Pipe lining (CIPP)
A trenchless method that pulls a resin-soaked liner into the old pipe and cures it in place, forming a new jointless pipe inside the old one. UV-cured liners are hardened with ultraviolet light. Lining cannot fix a collapsed pipe or a belly.
Root intrusion
Tree and shrub roots that grow into a sewer line through cracks or loose joints, especially in older clay pipe. Roots catch debris and cause recurring clogs, and over time they can widen the cracks.
Sewer camera inspection
Running a waterproof camera through a drain or sewer line to see and record its condition: the pipe material, joints, roots, cracks, offsets, and low spots. It is how a plumber decides between cleaning, repair, and replacement.
Sewer lateral
The private pipe that carries everything from your home's drains to the public sewer main, usually under the yard, sidewalk, or street. In Philadelphia the property owner is generally responsible for the lateral all the way to the main.
Terra-cotta (clay) pipe
Fired clay sewer pipe laid in short sections, common in older Philadelphia and Main Line laterals. The pipe itself is durable, but the joints between sections are where roots get in and sections shift.
Trenchless sewer repair
Repairing or replacing a sewer line through small access pits instead of a full-length trench. The two main methods are pipe lining and pipe bursting. Whether a line qualifies depends on what the camera shows.
Water service line
The pipe that brings drinking water from the public main in the street into your home, ending at the main shutoff and meter. In older homes it may be lead, galvanized steel, or copper.

Drains & Clogs

Drains services →
Cleanout
A capped access fitting on a drain or sewer line where a plumber can insert a cable, jetter hose, or camera without pulling a toilet. Many older homes have few or buried cleanouts, which can make clearing the main line harder.
Descaling
Removing the rust and mineral scale that builds up inside cast-iron drain pipes, using cutting heads or jetting. Heavy scale narrows the pipe and snags waste, causing slow drains.
Drain snake (auger)
A flexible steel cable with a cutting head that is fed into a drain to break up or pull out a clog. It opens the line quickly but leaves buildup on the pipe walls, which is why some clogs return.
Floor drain
A drain set in a basement or utility-room floor. Because it is often the lowest opening in the house, it is usually the first place sewage shows up when the main line or the public sewer backs up.
Hydro jetting
Cleaning a drain or sewer with a high-pressure water hose and nozzle that scours the inside of the pipe and flushes grease, scale, and roots out, rather than only punching a hole through a clog.
P-trap
The curved section of pipe under a sink or tub that holds a little water to keep sewer gas out of the room. A dry or clogged trap is a common cause of odors and slow drains.

Water Heaters

Water heaters services →
Anode rod
A metal rod inside a tank water heater that corrodes on purpose so the steel tank does not. When the rod is used up, the tank itself starts to rust, which is why anode checks are part of water heater maintenance.
First-hour rating
How many gallons of hot water a tank water heater can deliver in one busy hour, starting with a full tank. It is a better sizing guide than tank size alone and is printed on the unit's label.
Sediment buildup
Minerals from the water supply that settle at the bottom of a tank water heater. Sediment causes popping or rumbling, slows heating, and shortens tank life; flushing the tank is part of routine maintenance.
T&P relief valve
A safety valve on a water heater that opens if the temperature or pressure in the tank gets too high. Water dripping from its discharge pipe is a sign to have the heater checked, not a valve to cap.
Tankless water heater
A water heater that heats water as it flows through, instead of keeping a tank hot. It takes less space and does not run out the way a tank can, but it needs the right gas line, venting, and flow sizing for the household.

Plumbing Repair

Plumbing services →
Fill valve
The valve inside a toilet tank that refills it after a flush and shuts off when the float reaches the set level. A worn or mis-set fill valve lets water run down the overflow tube.
Flapper
The rubber seal at the bottom of a toilet tank that lifts to flush and drops to hold water. A worn or warped flapper is the most common reason a toilet runs.
Galvanized pipe
Steel pipe coated with zinc, common in homes built before the 1960s. Over decades it rusts from the inside, which narrows the pipe, lowers water pressure, and can tint water brown.
Pressure-reducing valve (PRV)
A valve near where the water service enters the house that lowers high street pressure to a safer level for pipes and fixtures. A failing PRV can cause either low pressure or pressure that is too high.
Sewage ejector pump
A pump in a sealed, vented basin that lifts wastewater from basement fixtures sitting below the sewer line, such as a basement bathroom or laundry, up into the main drain.
Sump pump
A pump set in a pit in the basement floor that removes groundwater and discharges it outside, away from the foundation. A float switch turns it on as water rises.
Wax ring
The wax seal between the base of a toilet and the flange, the fitting that connects the toilet to the drain. A failed wax ring can leak water onto the floor and let sewer gas into the room.

Heating

Heating services →
AFUE
Annual Fuel Utilization Efficiency, the U.S. Department of Energy rating for how much of a furnace or boiler's fuel becomes heat over a season. A higher AFUE means less fuel wasted up the flue.
Heat exchanger
The part of a furnace or boiler where heat from the burner passes into the air or water without the combustion gases mixing in. A cracked heat exchanger is a safety concern and often the point where replacement makes sense.
Hot-water (hydronic) heat
A heating system where a boiler heats water and a circulator pump moves it through radiators, baseboard, or tubing in the floor. Original Levittown homes often have hot-water radiant tubing in the slab.
Low-water cutoff
A safety control on a steam boiler that shuts off the burner if the water level drops too low. It needs regular flushing or testing; a dirty or failed cutoff is a common reason a steam boiler stops heating.
Steam boiler
A boiler that boils water into low-pressure steam, which rises to the radiators, gives off heat, condenses, and flows back as water. Common in older Philadelphia rowhomes and Main Line houses.

Air Conditioning

Cooling services →
Condensate line
The drain that carries water pulled out of the air by an AC coil, or produced by a high-efficiency furnace or boiler. When it clogs, a float switch often shuts the system off to prevent a leak.
Ductless mini-split
A heat pump with an outdoor unit and one or more wall or ceiling units connected by a small refrigerant line set, so it heats and cools without ductwork. A common fit for radiator-heated rowhomes.
Refrigerant (R-410A and newer)
The fluid an air conditioner or heat pump uses to move heat. Older R-22 systems were phased out, and newer equipment is moving away from R-410A under federal rules, which affects repair and replacement choices.
SEER2
The U.S. Department of Energy's current efficiency rating for central air conditioners and heat pumps. Higher SEER2 means less electricity for the same cooling. It replaced the older SEER rating for equipment made since 2023.

Emergencies & Safety

Emergency services →
Main water shutoff valve
The valve inside the house, usually where the water service enters near the meter, that turns off water to the whole home. Knowing where it is, and that it turns, is the first step in any leak emergency.

Commercial

Commercial services →
Grease trap (grease interceptor)
A tank that catches fats, oils, and grease from a commercial kitchen before they reach the sewer. Small under-sink units are often called grease traps; larger in-ground tanks are interceptors. Both need regular pumping.

General guidance, not a diagnosis of your home. Permit and code requirements differ by municipality and change over time; confirm current rules with Philadelphia L&I, your township, or your utility. Missing a term? Browse the Learning Center or call and ask a Pal.

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