Plumbing Guides
Plumbing glossary
The words on your estimate, your inspection report, and in our guides, in plain English. Where a guide covers a term in depth, it is linked.
4
- 4-point inspection
- An insurance inspection of the roof, electrical, HVAC, and plumbing on an older Florida home. The plumbing section notes pipe materials, water heater age, visible leaks, and the shutoff valve. Insurers use it to decide whether to write or renew a policy. Guide: The plumbing items on a Florida 4-point inspection, and how to pass them
A
- Aerator
- The small screened fitting screwed onto the tip of a faucet spout. It mixes air into the stream and catches sediment and scale. A clogged aerator is the most common cause of weak flow at one faucet, and it unscrews by hand for cleaning. Guide: Low water pressure at one faucet? Clean the aerator first
- Angle stop
- The small shutoff valve on the wall or floor under a sink or behind a toilet that feeds one fixture. Older multi-turn stops often seize or weep when finally turned; quarter-turn ball-style stops are the replacement. Guide: Toilet buying guide: flush power, height, and rough-in
- Anode rod
- A sacrificial metal rod inside a tank water heater that corrodes so the steel tank does not. In hard or softened water it can be used up in a few years. Replacing it on a younger tank extends the tank life. Guide: How old is my water heater, and when should I replace it?
B
- Backflow preventer
- A device that keeps water from flowing backward from a property into the public supply. Common types are the reduced pressure zone assembly (RPZ), the double check valve, and the pressure vacuum breaker (PVB). Utilities require annual testing on most of them. Guide: Backflow testing: why the utility sent me a letter and what happens next
- Belly
- A low spot in a buried drain line where the pipe has settled and holds standing water and solids. Bellies show on a camera inspection as a section that stays submerged, and they cause repeat clogs at the same place. Guide: Buying an older home with cast iron drain lines? Get the sewer line scoped first
C
- Cabling
- Clearing a drain with a motorized steel cable, also called snaking or rodding. A cutting head on the cable bores through roots, wipes, and soft blockages. It opens the line but does not scrub the pipe walls the way jetting does. Guide: Hydro jetting vs. cabling: which drain cleaning does your line need?
- Cartridge
- The replaceable valve inside a single-handle faucet or shower valve that controls flow and mixes hot and cold. Scale and worn seals make it drip or stiffen. Most major brands cover the cartridge under a lifetime warranty. Guide: Shower dripping or hard to turn? Replacing the shower valve cartridge
- Cast iron
- The heavy black drain and sewer pipe used under and inside most Southwest Florida homes built before the mid-1970s. It rusts from the inside, scales, and eventually channels or collapses. A camera inspection shows its condition. Guide: Buying an older home with cast iron drain lines? Get the sewer line scoped first
- Channeling
- Corrosion that eats away the bottom of a cast iron drain pipe where water sits, leaving a trough in the soil instead of pipe. Channeled sections catch solids, leak into the ground, and usually mean that run needs replacement. Guide: Cast iron, galvanized, copper, CPVC, polybutylene, PEX: what pipes are in your Florida home?
- Chloramine
- A disinfectant made from chlorine and ammonia that many utilities use because it lasts longer in the pipes than chlorine alone. It is harder on rubber seals, must be removed for aquariums and dialysis, and needs catalytic carbon to filter out. Guide: Chloramine in Southwest Florida tap water: skin, hair, aquariums, and what a filter can do
- Cleanout
- A capped access fitting on a drain or sewer line, usually a PVC or brass cap at grade near the front or side of the house. A plumber opens it to run a cable, jetter, or camera without pulling a toilet. Guide: Why are several drains backing up at the same time?
- Closed system
- A home plumbing system where a backflow preventer or pressure reducing valve keeps water from expanding back toward the street. Heated water then has nowhere to go and pressure spikes, which is why a closed system needs an expansion tank. Guide: Expansion tanks: why your new water heater came with one
- CPVC
- Chlorinated polyvinyl chloride, the cream or tan colored rigid plastic supply pipe common in Florida homes from the 1980s onward. It turns brittle with age, heat, and chlorinated water, and cracks at fittings, often in attics and garages. Guide: Signs your CPVC pipes are failing
D
- Double check valve
- A backflow preventer with two spring-loaded check valves in series, used where the hazard is low, such as fire sprinklers and some irrigation. It has no relief port, so it can be installed below grade. It needs annual testing. Guide: Backflow testing: why the utility sent me a letter and what happens next
E
- Expansion tank
- A small steel tank with an air bladder installed on the cold line near the water heater. It absorbs the expansion of heated water in a closed system so pressure does not spike and the relief valve does not weep. Guide: Expansion tanks: why your new water heater came with one
F
- Fill valve
- The tall valve inside a toilet tank that refills the tank after a flush and shuts off at the set water level. A worn fill valve refills on its own or never quite stops, which is one cause of a running toilet. Guide: Toilet keeps running? How to adjust or replace the fill valve
- Flange
- The ring fitting at floor level that connects a toilet to the drain pipe and anchors the closet bolts. A cracked, corroded, or low flange lets the toilet rock and the wax ring fail, and it must be repaired before a new toilet goes down. Guide: Toilet buying guide: flush power, height, and rough-in
- Flapper
- The rubber seal at the bottom of a toilet tank that lifts to flush and drops to hold water. Chlorine and chloramine wear it out, and a leaking flapper silently drains the tank and refills it, raising the water bill. Guide: Why is my water bill so high? Check your toilets first
H
- Hardness (grains per gallon)
- A measure of dissolved calcium and magnesium in water. One grain per gallon is about 17 milligrams per liter. Water above roughly 7 grains is considered hard and leaves scale on heaters, fixtures, and glass; much Lee and Collier County water is in that range. Guide: What hard water actually costs you in a Southwest Florida home
- Hose bib
- An outdoor faucet with a threaded spout for a garden hose. Also called a sillcock or spigot. The washer and packing wear out and drip, and it is the handiest place to screw on a gauge to test house water pressure. Guide: Outdoor hose bib leaking? How to fix a dripping spigot
- Hydro jetting
- Cleaning a drain line with a high-pressure water hose and a nozzle that scours the pipe walls while pulling itself forward. It removes grease, scale, and root mats that a cable only bores through. Not used on badly damaged pipe. Guide: Hydro jetting vs. cabling: which drain cleaning does your line need?
L
- Lift station
- A pump chamber that raises sewage from a low point to a higher sewer line when gravity cannot carry it. Utilities run neighborhood lift stations; some homes and condos have a private one that fails in a power outage. Guide: Sewage backup in the house: safety first, then who to call
M
- Main shutoff
- The valve that stops all water to the house, usually where the supply enters, near the garage or an exterior wall, sometimes at the meter. Every household member should know where it is and confirm it actually closes. Guide: Where is my main water shutoff valve, and should I close it when I leave town?
- Manifold
- A distribution block, usually in a PEX repipe, where the main splits into individual lines to each fixture, each with its own shutoff. It lets one fixture be isolated without shutting the whole house. Guide: How long does a repipe take, and what happens each day?
- MaP score
- Maximum Performance rating, an independent test of how many grams of waste a toilet clears in one flush, up to 1,000. Higher is better; a score of several hundred or more means a low-flow toilet that flushes once. Guide: Toilet buying guide: flush power, height, and rough-in
- Meter box
- The in-ground box near the street holding the utility water meter and often a shutoff valve. The meter has a small leak indicator that spins when water is flowing, which is the first check for a hidden leak. Guide: No water at all? Meter, well pump, or utility
O
- Owner-builder
- A Florida permit exemption that lets a homeowner pull a permit and do certain work on their own primary residence without a license. It carries conditions and liability, and it does not apply to rental property or to hiring unlicensed help. Guide: What does a plumbing permit actually cover, and why should I care?
P
- P-trap
- The U-shaped bend under every sink, tub, and shower drain that holds a plug of water to keep sewer gas out of the house. A dry trap in an unused fixture is the usual source of a sewer smell. Guide: Bathroom sink draining slowly? Clean the pop-up stopper and the P-trap
- Permit
- Authorization from the city or county to do regulated plumbing work, followed by an inspection. Water heater replacement, repipes, backflow devices, and sewer work are typically permitted; unpermitted work can surface at sale or in an insurance claim. Guide: What does a plumbing permit actually cover, and why should I care?
- PEX
- Cross-linked polyethylene, the flexible red, blue, or white tubing used in most modern repipes. It tolerates heat and chlorinated water better than CPVC, bends around corners with fewer fittings, and is the usual replacement material in Southwest Florida. Guide: PEX vs CPVC for a repipe in a Florida home
- Polybutylene
- Gray flexible plastic supply pipe installed in many Florida homes from the late 1970s to mid-1990s. Chlorine makes it brittle from the inside and it fails without warning. Insurers often refuse or restrict coverage until it is replaced. Guide: Does my home have polybutylene pipes, and what should I do about them?
- PRV
- Pressure reducing valve, a spring-loaded regulator on the main line that holds house pressure at a set level regardless of street pressure. Needed when supply pressure is high or variable. A failing PRV lets pressure creep up or fluctuate. Guide: Do I need a whole-house water pressure regulator?
- PVB
- Pressure vacuum breaker, a backflow preventer common on irrigation systems. It must be installed above the highest sprinkler head and above grade, which is why it sits exposed and cracks when it freezes or gets hit by a mower. Guide: Backflow testing: why the utility sent me a letter and what happens next
R
- Reclaimed water
- Treated wastewater piped to some neighborhoods for irrigation only, usually in purple pipe. It must never connect to household plumbing, and homes with reclaimed irrigation often have separate backflow requirements. Guide: Backflow testing: why the utility sent me a letter and what happens next
- Repipe
- Replacing all the water supply pipes in a house, usually with PEX run through the attic and walls, and abandoning the old CPVC, polybutylene, or slab-buried copper. Permitted work that takes a few days and includes drywall patching. Guide: Repiping an older Southwest Florida home: when it is time and what to expect
- Reverse osmosis
- A filtration method that forces water through a fine membrane, removing most dissolved minerals, salts, and contaminants. Usually installed under the kitchen sink for drinking water. It sends reject water to the drain and needs periodic filter changes. Guide: Do I need a reverse osmosis system under the kitchen sink?
- Riser
- A vertical water supply pipe serving multiple floors, most often in a condo or apartment building. Risers are usually association property, and replacing them is a building-wide project that affects every unit they pass through. Guide: Condo plumbing: what is yours to fix and what belongs to the association?
- Rough-in
- The pipes and fittings installed in walls and floors before fixtures go on. For a toilet, the rough-in is the distance from the finished wall to the center of the drain, usually 12 inches, and it determines which toilets fit. Guide: Toilet buying guide: flush power, height, and rough-in
- RPZ
- Reduced pressure zone assembly, the backflow preventer required where the hazard is highest, such as commercial properties and many condos. It has two checks and a relief valve that dumps water when a check fails, so it must sit above grade. Guide: Backflow testing: why the utility sent me a letter and what happens next
S
- Salt-free conditioner
- A whole-home treatment that changes how hardness minerals behave so they are less likely to stick as scale, without removing them. It uses no salt or drain and needs little maintenance, but it does not soften water the way an exchange softener does. Guide: I have a water softener. Do I still need a filter?
- Scale
- The hard white or tan mineral crust left by hard water on heating elements, aerators, showerheads, and inside pipes and tank water heaters. It reduces flow, insulates heaters so they work harder, and shortens the life of fixtures. Guide: What hard water actually costs you in a Southwest Florida home
- Sediment
- Sand, silt, rust, and mineral particles carried in water. In a tank water heater it settles on the bottom and causes rumbling and early failure; on a well it clogs screens and valves. A sediment filter catches it before the house. Guide: Well water testing checklist for Lehigh Acres, Alva, and rural Lee County homes
- Septic drain field
- The buried network of perforated pipes in gravel or chambers where liquid from a septic tank soaks into the soil. Standing water, lush grass over the field, or slow drains after rain mean it is saturated or failing. Guide: On a septic system in Lehigh Acres or Alva? The basics every owner should know
- Sillcock
- Another name for an outdoor hose faucet, from the sill of the house it mounts through. Frost-free sillcocks have a long stem that closes inside the wall; standard ones close at the spout. See hose bib. Guide: Outdoor hose bib leaking? How to fix a dripping spigot
- Slab leak
- A leak in a water line running under or through the concrete slab foundation that most Southwest Florida homes sit on. Signs are a warm spot on the floor, a running meter, or damp flooring. Repair is a spot fix or a reroute overhead. Guide: Signs of a slab leak in a Florida home, and what happens next
- Stack
- A vertical drain pipe that carries waste from upper floors down to the building drain, with a vent continuing up through the roof. In older condos the stack is often original cast iron, and it is usually association property. Guide: Condo plumbing: what is yours to fix and what belongs to the association?
- Supply line
- The short flexible hose connecting a shutoff valve to a faucet, toilet, washing machine, or ice maker. Braided stainless lines outlast plastic or rubber ones. Old supply lines are one of the leading causes of house floods. Guide: Are your washing machine hoses rubber? Replace them with braided stainless steel
T
- T&P relief valve
- The temperature and pressure relief valve on a water heater. It opens to release water if the tank gets too hot or the pressure climbs too high, discharging through a pipe toward the floor or outside. A dripping one is a warning sign. Guide: Water heater in a closet or attic: pans, drains, and what code wants
- Trapway
- The curved internal passage in a toilet bowl that carries waste from the bowl to the drain. A wider, fully glazed trapway clogs less and flushes better at low water volume; cheap toilets narrow it to save material. Guide: Toilet buying guide: flush power, height, and rough-in
V
- Vent stack
- The pipe that runs up through the roof to let air into the drain system so water flows freely and traps keep their seal. A blocked vent, from a bird nest or debris, causes gurgling drains and sewer smells. Guide: Why are several drains backing up at the same time?
W
- Water hammer
- The bang in the pipes when a valve closes quickly and moving water stops all at once. Common with washing machines and dishwashers. High pressure makes it worse; a pressure regulator and hammer arrestors at the appliance quiet it. Guide: Do I need a whole-house water pressure regulator?
- Water softener
- A whole-home unit that removes hardness minerals by exchanging them for sodium or potassium on a resin bed, then regenerates with a salt brine that goes to the drain. It stops scale but adds a little sodium to the water. Guide: I have a water softener. Do I still need a filter?
- WaterSense
- A federal labeling program for fixtures that use less water while meeting performance standards. A WaterSense toilet uses 1.28 gallons per flush or less; faucets and showerheads carry the label too. Some utilities offer rebates for labeled fixtures. Guide: Toilet buying guide: flush power, height, and rough-in
- Wax ring
- The wax gasket that seals the base of a toilet to the flange so water and sewer gas stay in the drain. It fails when the toilet rocks or the flange sits too low. Wax-free rubber seals are a modern alternative. Guide: Toilet buying guide: flush power, height, and rough-in
These guides are for general information only. Plumbing work can involve water damage, electricity, gas, permits, and code requirements, and every home is different. If you are not sure, stop and call a licensed plumber. Do-it-yourself work is at your own risk. Read the full disclaimer.