Plumbing Terms and Definitions: Your Bay Area Plumbing Glossary

A

ABS (Acrylonitrile Butadiene Styrene)
Think of this as the black plastic pipe you might see under your sink or behind your walls. It’s tough, lightweight, and commonly used for drain lines in Bay Area homes. If you’ve ever wondered what that black pipe is, now you know!

Absorption Field
This is part of a septic system—basically a special area in your yard where wastewater slowly soaks into the ground after being treated. Not super common in San Jose proper, but if you’re out in Morgan Hill or Gilroy, you might have one.

Access Panel
That little door in your wall or ceiling that lets plumbers reach pipes without tearing everything apart. Think of it as a secret passage for your plumbing system!

Activated Carbon
A fancy water filter material made from heated materials like coconut shells or wood. It’s great at removing chlorine taste and smell from your water—something many Bay Area residents appreciate for better-tasting drinking water.

Adaptor
A connector piece that joins two different types of pipes together. Like a universal charger for your pipes! For example, connecting modern plastic pipes to older cast iron ones in historic Bay Area homes.

Aerator
That little screen at the tip of your faucet that mixes air with water. It helps reduce splashing and saves water—perfect for California’s water conservation goals. If your faucet flow seems weak, the aerator might just need cleaning!

Pro Tip: In the Bay Area’s hard water areas like San Jose and Cupertino, aerators can get clogged with mineral deposits. Unscrew it every few months and soak it in vinegar overnight to restore full flow. This simple trick can save you from thinking you need a whole new faucet!

Air Admittance Valve
A modern alternative to traditional vent pipes that lets air into your drain system without needing a pipe through your roof. Great for remodels in older Bay Area homes where adding traditional vents is tricky.

Angle Stop
The small valve under your sink or behind your toilet that lets you shut off water to just that fixture. Every Bay Area homeowner should know where these are—they’re lifesavers during plumbing emergencies!

Anode Rod
A sacrificial metal rod inside your water heater that corrodes instead of your tank. Think of it as taking a bullet for your water heater. In the Bay Area’s mineral-rich water, these need checking every few years.

Pro Tip: Bay Area water can be particularly hard on anode rods. If you notice a rotten egg smell from your hot water, it might be time to replace this rod. This $20 part can extend your water heater’s life by years—especially important given our high cost of living!

Anti-Scald Valve
A safety device that prevents water from getting dangerously hot. Essential if you have kids or elderly family members. California building codes now require these in new construction.

Anti-Siphon
A device that prevents water from flowing backward into your clean water supply. You’ll find these on outdoor faucets and sprinkler systems throughout the Bay Area.

B

Back Pressure
Pressure that pushes against the normal flow direction in your pipes. Imagine trying to blow through a straw while someone’s blowing from the other end—that’s back pressure!

Backflow
When water flows the wrong way in your plumbing system. This is a big deal because contaminated water could mix with your drinking water. That’s why backflow preventers are required on irrigation systems in San Jose and throughout Santa Clara County.

Backflow Preventer
A valve that acts like a one-way door for water—it can flow forward but not backward. Required by Bay Area building codes for sprinkler systems and certain plumbing fixtures.

Pro Tip: If you have an irrigation system in your Saratoga or Los Gatos yard, California law requires annual backflow testing. Drain and Water can handle this for you—it’s quick, affordable, and keeps your drinking water safe!

Backup
When water or waste overflows from a fixture because the drain is clogged. Not fun, but common in older Bay Area homes with mature tree roots invading sewer lines.

Ballcock
The fill valve inside your toilet tank that controls water flow. When you flush, it opens to refill the tank. If your toilet keeps running, this is often the culprit.

Basin Wrench
A specialized tool with a long handle that reaches up behind sinks to tighten faucet nuts. Plumbers love these, but they’re awkward for DIYers—one reason to call the pros!

Basket Strainer
The removable strainer in your kitchen sink that catches food scraps. Pro tip: Actually use it! It prevents clogs and saves you money on drain cleaning.

Bidet
A bathroom fixture for personal hygiene that’s becoming more popular in Bay Area homes. Think of it as a low sink specifically for washing up.

Bleed
To release air or water from a pipe or system. Like when you “bleed” radiators in older Bay Area homes with hydronic heating.

BTU (British Thermal Unit)
A measurement of heat energy. When shopping for water heaters in the Bay Area, higher BTUs mean faster water heating—important for larger families.

Burner
The part of a gas water heater or boiler where the flame heats the water. If you smell gas near your water heater in your San Jose garage, shut off the gas and call us immediately at (408) 564-0580.

C

Catch Basin
A large underground container with a grate on top that collects rainwater runoff. Common in Bay Area driveways and parking areas—they help prevent flooding during our winter rains.

Centerset
A bathroom faucet style where the handles are 4 inches apart. This is the most common type you’ll see in Bay Area homes.

Check Valve
A valve that only lets water flow one direction. Think of it as a turnstile for water—you can only go through one way.

Chloramines
A disinfectant used in many Bay Area water systems instead of straight chlorine. It’s a combination of chlorine and ammonia that keeps water safe but can affect aquarium fish—something to know if you’re a fish keeper!

Circuit Vent
A vent pipe that serves multiple fixtures in your home’s drain system. It’s part of the behind-the-walls plumbing that keeps everything flowing smoothly.

Cleanout Plug
A removable plug in your drain line that gives plumbers access to clear clogs. If you have one in your yard or basement, knowing its location can save time during emergencies.

Pro Tip: Many Bay Area homes built before 1950 don’t have adequate cleanouts. If your home is in Willow Glen, Japantown, or other historic San Jose neighborhoods, consider having Drain and Water install additional cleanouts during your next sewer service—it makes future maintenance much easier and less expensive!

Closed System
A plumbing system where water can’t expand when heated because of devices like check valves or backflow preventers. This is increasingly common in Bay Area homes and requires an expansion tank to prevent damage.

Closet
Plumber-speak for a toilet. So a “closet auger” is actually a tool for unclogging toilets!

Closet Auger
A specialized snake tool designed specifically for clearing toilet clogs. It has a curved end that navigates the toilet’s built-in trap.

Closet Flange
The ring that anchors your toilet to the floor and connects it to the drain pipe. If your toilet rocks or leaks at the base, this might be broken—common in older Bay Area homes.

Compression Fitting
A type of pipe connection that uses a nut and ring to create a watertight seal without soldering. Great for repairs and DIY-friendly!

CPVC (Chlorinated Polyvinyl Chloride)
A rigid plastic pipe used for hot and cold water lines in some Bay Area homes. It’s cream-colored and can handle hot water, unlike regular PVC.

Pro Tip: CPVC was popular in Bay Area construction from the 1980s-2000s, but it can become brittle over time, especially in our hot attics. If you have CPVC and notice pinhole leaks, it might be time to consider repiping. Drain and Water specializes in trenchless repiping that minimizes disruption to your home!

D

Degree Rise (Delta T)
The difference between your incoming cold water temperature and your desired hot water temperature. In the Bay Area, our cold water is typically 55-60°F, so heating to 120°F requires a 60-65° rise.

Diaphragm
A flexible membrane in valves that controls water flow. Think of it like a flexible door that opens and closes.

Dip Tube
A tube inside your water heater that sends cold water to the bottom of the tank where it gets heated. If this breaks, you’ll get lukewarm showers because cold water mixes with hot at the top.

Discharge Tube
The outlet pipe that carries water away from your garbage disposal or sump pump.

Diverter
A valve that redirects water flow—like the knob on your tub that switches water from the faucet to the showerhead.

Drain Valve
The valve at the bottom of your water heater used for draining and flushing sediment. Bay Area water can be hard, so flushing your water heater annually extends its life.

DWV (Drain, Waste, and Vent)
The system of pipes that carries wastewater out of your home and allows air in to keep everything flowing. It’s like the exhaust system for your plumbing.

E

ECO (Energy Cut Off)
A safety device on water heaters that shuts off power if temperatures get dangerously high. It’s a safety feature that prevents fires and scalding.

EF (Energy Factor)
A rating that tells you how efficient a water heater is. Higher numbers mean lower energy bills—important in the Bay Area where PG&E rates keep climbing!

Elbow
A curved pipe fitting that changes the direction of your plumbing. They come in different angles—90° elbows make right-angle turns, while 45° elbows make gentler curves.

Escutcheon
The decorative plate that covers the hole in your wall or sink where the faucet comes through. It’s both functional and makes things look finished.

Expansion Tank
A small tank (usually red or blue) near your water heater that absorbs pressure when water expands from heating. Required by code in many Bay Area jurisdictions with closed plumbing systems.

Pro Tip: If you’ve had a backflow preventer or pressure-reducing valve installed in your San Jose or Palo Alto home, you likely have a closed system and NEED an expansion tank. Without one, you risk damaging your water heater, pipes, and fixtures. Drain and Water can assess your system and install one if needed—it’s a small investment that prevents expensive damage!

F

Fall/Flow
The downward slope of drain pipes that allows gravity to move wastewater. Proper slope is critical—too flat and waste doesn’t flow; too steep and water outruns solids, leaving them behind.

Female Fitting
A fitting with threads on the inside that receives a male fitting. Think of it like a socket that something screws into.

First Hour Delivery
How much hot water your water heater can supply in the first hour of use. Important for Bay Area families—if you have teenagers taking long showers, you need adequate first-hour delivery!

Fixture
Any device that uses or drains water—sinks, toilets, tubs, showers, etc. Basically, the plumbing stuff you actually see and use.

Flapper Valve
The rubber seal at the bottom of your toilet tank that lifts when you flush. If your toilet runs constantly, this is often worn out and needs replacing—an easy DIY fix!

Float Ball
The ball inside your toilet tank that rises and falls with the water level, controlling when the tank fills and stops filling.

Flow Control Valve
A device that limits water flow to save water and energy. California now requires low-flow fixtures in new construction—good for your wallet and the environment!

Flow Rate
How much water flows through a fixture, measured in gallons per minute (GPM). California requires showerheads to be 2.0 GPM or less—a big change from older 5 GPM models!

Flue
The pipe that carries combustion gases from your gas water heater or furnace to the outside. Proper venting is critical for safety—carbon monoxide is no joke!

Flushometer
The type of flush valve you see in commercial bathrooms that uses water pressure instead of a tank. They’re powerful and fast—that’s why they’re in restaurants and offices throughout the Bay Area.

Flux
A paste applied to copper pipes before soldering that helps the solder flow and bond properly. It’s like primer for pipe joints.

French Drain
A gravel-filled trench with a pipe that redirects water away from your home. Popular in Bay Area yards for managing our winter rains and preventing foundation problems.

G

Galvanic Action
When two different metals touch in water, one corrodes faster. This is why you shouldn’t connect copper pipes directly to galvanized steel—you need a special dielectric fitting.

Gate Valve
A valve with a gate that slides up and down to control flow. Common on main water lines, but they can stick if not used regularly.

Pro Tip: Many Bay Area homes have a main gate valve that hasn’t been turned in decades. Test yours annually by turning it off and back on—if it’s stuck or leaking, replace it before you have an emergency. Drain and Water can upgrade you to a modern ball valve that’s more reliable!

Gray Water
Wastewater from sinks, showers, and washing machines (but not toilets). Some Bay Area homeowners are installing graywater systems to irrigate landscaping—a great water conservation strategy!

Gravity Operated Toilet
A standard toilet that uses the weight of water falling from the tank to create the flush. This is what most Bay Area homes have.

H

Head Loss
The reduction in water pressure as water moves through pipes. Long pipe runs or small pipes increase head loss—something to consider in larger Bay Area homes.

Heat Trap
A device or loop in pipes that prevents heat from escaping your water heater through the pipes. Saves energy and money!

Horizontal Branch
The drain pipes that run horizontally from fixtures to the main vertical drain stack.

Hose Bibb
The outdoor faucet where you connect your garden hose. In the Bay Area, these should have backflow preventers and frost-free designs (even though we rarely freeze!).

House Trap
A U-shaped trap in your main drain line, common in older Bay Area homes. Modern codes don’t require them, and they can be a clog point.

Hydro Jetting
A powerful drain cleaning method using high-pressure water to blast away clogs, grease, and tree roots. This is Drain and Water’s specialty—it’s way more effective than snaking for tough Bay Area sewer line clogs!

Pro Tip: If you have recurring drain problems in your San Jose or Sunnyvale home, especially with mature trees nearby, hydro jetting can clear years of buildup and root intrusion. It’s more thorough than traditional snaking and can extend the life of your sewer line. Ask Drain and Water about our video inspection + hydro jetting combo service!

I

ID (Inside Diameter)
How pipes are measured—by the inside diameter, not the outside. A 1/2″ pipe has a 1/2″ inside diameter.

Indirect Waste
A drain that empties into another fixture rather than directly into the drain system. Like when your washing machine drains into a laundry sink.

Instantaneous Water Heater
Another name for a tankless water heater—it heats water on demand as it flows through. Popular in Bay Area homes for endless hot water and energy savings!

J

Jet
The opening in a toilet bowl that shoots water into the trapway to start the siphon action during flushing.

Johnni-Bolts
The bolts that secure your toilet to the floor. If your toilet rocks, these might be loose or the flange might be damaged.

L

Lavatory
The fancy plumbing term for a bathroom sink. Also sometimes means the whole bathroom.

Leach Field
The area where septic system wastewater soaks into the ground. If you’re in rural parts of Santa Clara County, you might have one.

Leader
A pipe that carries rainwater from your roof gutters to the ground or storm drain. Important during Bay Area rainy season!

Lock Nut
A nut that locks fittings together to prevent them from loosening. Common under sinks and on toilet connections.

M

Main
The primary supply or drain line that all branches connect to. Your main water line brings water from the street to your home; your main drain carries all wastewater out.

Male Threads
Threads on the outside of a pipe or fitting that screw into female threads.

Manifold
A fitting that splits one line into multiple branches. Think of it as a distribution hub for your plumbing.

Mixing Valve
A valve that blends hot and cold water to achieve a specific temperature. Modern ones prevent scalding—a great safety feature for Bay Area families.

N

Natural Gas
The fuel used by most Bay Area water heaters and furnaces, delivered by PG&E. If you smell gas (like rotten eggs), get out and call PG&E immediately!

Nipple
A short piece of pipe with threads on both ends used to connect fittings. Despite the funny name, it’s a standard plumbing part!

No-Hub Connector
A rubber sleeve with clamps used to connect pipes, especially when joining new plastic pipes to old cast iron—common in Bay Area home renovations.

O

O-Ring
A round rubber washer that creates watertight seals, especially around faucet stems. If your faucet drips, a worn O-ring is often the culprit.

Oakum
A tarred rope material used to seal joints in old cast iron pipes. You’ll find this in historic Bay Area homes built before 1960.

One-Piece Toilet
A toilet where the tank and bowl are one seamless unit. They’re sleeker and easier to clean than traditional two-piece toilets.

P

Packing
Material used in faucets to prevent leaks around the stem. When it wears out, you get that annoying drip.

PB (Polybutylene)
A gray plastic pipe used in some Bay Area homes from the 1970s-1990s. It’s prone to failure and many insurance companies won’t cover homes with it. If you have PB pipe, consider repiping!

Pro Tip: Polybutylene pipe was used in many Bay Area homes built between 1978-1995, especially in San Jose subdivisions. It’s now known to fail prematurely, causing water damage. If you’re buying a home with PB pipe, factor in repiping costs. Drain and Water offers trenchless repiping that’s faster and less disruptive than traditional methods!

pH
A measure of how acidic or alkaline your water is, on a scale of 0-14. Seven is neutral; below is acidic, above is alkaline. Bay Area water is typically slightly alkaline.

Pilot
The small flame that stays lit on gas water heaters and furnaces, ready to ignite the main burner when needed.

Pipe Dope
Slang for pipe joint compound—a paste applied to threaded connections to create watertight seals.

Pitch
The slope of a drain pipe. Proper pitch is essential for drainage—typically 1/4 inch drop per foot of horizontal run.

Plumb
Perfectly vertical. Also means to install or work on plumbing systems.

Plumber’s Putty
A soft, pliable sealing compound used around drains and faucets. It stays flexible and creates watertight seals.

Plunger
The rubber cup on a stick you use to unclog drains and toilets. Every Bay Area home should have one! Use a cup plunger for sinks and a flange plunger for toilets.

Pop-Up Drain
The type of sink drain that opens and closes with a lever behind the faucet. Common in bathroom sinks throughout the Bay Area.

Pressure Balance Valve
A shower valve that maintains consistent temperature even when someone flushes a toilet or starts the dishwasher. No more shower surprises!

Pressure Reducing Valve (PRV)
A valve that reduces high street water pressure to a safer level for your home. Many Bay Area neighborhoods have high water pressure (80+ PSI) that can damage fixtures and appliances—a PRV protects your plumbing.

Pro Tip: High water pressure is common in hillside Bay Area neighborhoods like Los Gatos, Saratoga, and parts of San Jose. If your water pressure exceeds 80 PSI, you need a pressure-reducing valve to protect your plumbing and a thermal expansion tank to handle pressure from water heating. Drain and Water can test your pressure and install both if needed!

PVC (Polyvinyl Chloride)
White or cream-colored plastic pipe used for drain, waste, and vent systems. It’s durable, affordable, and common in Bay Area homes.

Q

Quick Connect
A fitting that snaps onto pipes without tools—common on modern faucet supply lines. They make installation and replacement much easier!

R

Reamer
A tool used to smooth rough edges inside pipes or to resurface valve seats in faucets.

Recovery Rate
How quickly a water heater can heat new water after the tank is depleted. Important for large Bay Area families!

Reducer
A fitting that connects pipes of different sizes—like going from 3/4″ to 1/2″ pipe.

Revent
A vent pipe specifically for a fixture trap, connecting to the main vent system above the fixture.

Reverse Osmosis (RO)
A water filtration system that forces water through a membrane to remove impurities. Popular in the Bay Area for drinking water—it removes minerals, chemicals, and contaminants.

Riser
The supply line that connects a faucet to the shutoff valve, or a vertical pipe that carries water between floors.

Rough-In
The stage of plumbing installation where pipes are installed in walls and floors before finishing work. This happens before drywall goes up.

Rough-In Dimensions
The measurements from walls and floors to where plumbing connections need to be. Critical when replacing toilets or fixtures—Bay Area homes have varying rough-in dimensions!

S

Saddle Valve
A valve that clamps onto a pipe and taps into it without cutting. Often used for ice maker connections, though modern plumbers prefer better methods.

Sanitary Sewer
The drain system that carries wastewater from your home to the municipal sewer or septic system.

Self-Rimming Sink
A sink with a built-in lip that sits on top of the counter. Easy to install and common in Bay Area kitchens.

Sewer Camera Inspection
Using a waterproof camera to look inside sewer lines and diagnose problems. Drain and Water uses this technology to pinpoint issues without guessing—especially valuable in older Bay Area homes!

Pro Tip: Before buying a Bay Area home, especially one built before 1980, consider getting a sewer camera inspection. Tree roots, aging clay pipes, and bellied lines are common issues that can cost thousands to repair. Drain and Water offers pre-purchase sewer inspections that can save you from expensive surprises!

Slip Joint
A connection that slides together and is sealed with a washer and nut—common under sinks. They’re designed to be taken apart for cleaning or repairs.

Soil Stack
The main vertical drain pipe that carries wastewater from all your fixtures down to the sewer line.

Solder
Metal alloy melted to join copper pipes. Also the act of joining pipes this way. Proper soldering creates permanent, leak-free connections.

Stack
Any vertical drain or vent pipe in your plumbing system.

Stop Valve
The shutoff valve under sinks and toilets. Know where yours are—they’re essential during plumbing emergencies!

Sump
A pit that collects water, usually with a pump to remove it. Not common in most Bay Area homes, but essential in areas with high water tables.

Sweating
Plumber slang for soldering copper pipes. Also refers to condensation forming on cold pipes or toilet tanks—common in humid Bay Area bathrooms.

T

T&P Valve (Temperature & Pressure Relief Valve)
A critical safety device on water heaters that releases pressure if temperature or pressure gets too high. If this valve is dripping, don’t ignore it—call Drain and Water at (408) 564-0580!

Tailpiece
The straight pipe section that connects a sink drain to the P-trap below.

Tank
The upper part of a toilet that holds water for flushing. Also refers to water heater storage tanks.

Tankless Water Heater
A water heater that heats water on demand without a storage tank. Popular in Bay Area homes for energy efficiency and endless hot water—perfect for those long California showers!

Pro Tip: Tankless water heaters are great for Bay Area homes, but they require proper sizing and installation. Undersized units won’t keep up with demand, and our hard water requires regular descaling. Drain and Water can help you choose the right size and maintain it properly for years of reliable service!

Tee
A T-shaped fitting that creates a branch line off a main pipe.

Thermal Expansion
When water heats up, it expands. In closed plumbing systems (common in the Bay Area), this creates pressure that can damage your system—that’s why expansion tanks are important!

Thermocouple
A safety device on gas water heaters that shuts off gas if the pilot light goes out. If your pilot won’t stay lit, the thermocouple might need replacing.

Trap
The curved section of drain pipe under fixtures that holds water to prevent sewer gases from entering your home. Every fixture needs one—it’s that U-shaped pipe under your sink!

Trap Seal
The water sitting in your trap that blocks sewer gases. If you smell sewer odors, a trap might have dried out or lost its seal.

Trapway
The channel in a toilet that connects the bowl to the drain. Wider trapways (2″ or more) are less likely to clog—important if you have kids!

Trip Lever
The handle you push to flush a toilet. Also the lever that opens bathtub drains.

Trenchless Technology
Modern methods for repairing or replacing underground pipes without digging trenches. This is Drain and Water’s specialty—we use patented TrenchFree™ methods to fix sewer and water lines without destroying your Bay Area landscaping!

Pro Tip: Traditional sewer line replacement means digging up your driveway, landscaping, and hardscaping—costing thousands extra beyond the pipe work. Drain and Water’s TrenchFree™ technology can reline or replace pipes with minimal digging, saving you money and preserving your property. We’re the Bay Area’s pioneers in trenchless plumbing!

U

Union
A three-piece fitting that joins pipes but allows them to be disconnected without cutting. Useful for future maintenance.

Usable Storage
The amount of hot water you can actually use from a water heater before the temperature drops too low. Typically 70-80% of the tank capacity.

V

Vacuum Breaker
A device that prevents contaminated water from being sucked back into your clean water supply. Required on outdoor faucets and irrigation systems throughout the Bay Area.

Valve Seat
The stationary part of a valve that the moving part seals against. When worn, it causes leaks.

Vent
Pipes that allow air into your drain system to maintain proper pressure and prevent trap siphoning. They typically exit through your roof.

Vent Stack
The main vertical vent pipe that extends through your roof, allowing sewer gases to escape and air to enter the drain system.

Vitreous China
The ceramic material used to make toilets, sinks, and bidets. It’s fired at high temperatures to create a smooth, non-porous, easy-to-clean surface.

W

Waste & Overflow
The drain assembly in bathtubs that includes both the bottom drain and the overflow opening near the top of the tub.

Water Hammer
That loud banging noise when you quickly shut off a faucet. It’s caused by pressure waves in your pipes and can damage your plumbing over time. Water hammer arrestors can fix this common Bay Area home problem.

Water Hardness
The amount of dissolved minerals (mainly calcium and magnesium) in water. Bay Area water varies from moderately hard to very hard depending on your location—San Jose and South Bay tend to have harder water.

Pro Tip: Hard water is a fact of life in much of the Bay Area. It causes scale buildup in pipes, water heaters, and fixtures, reducing efficiency and lifespan. Consider a water softener or at minimum, flush your water heater annually. Drain and Water can test your water hardness and recommend solutions!

Wet Vent
A vent pipe that also serves as a drain—it does double duty in your plumbing system.

Widespread
A bathroom faucet style with separate spout and handles, typically 8 inches apart. Popular in upscale Bay Area bathroom remodels.

Wye (Y-Fitting)
A Y-shaped fitting used to create branch lines at a 45-degree angle. Common in drain systems.

Y

Yoke
The part of a faucet that holds the hot and cold valves and mixing chamber. Also refers to a pipe support assembly.

Yoke Vent
A vent connecting a soil or waste stack to a vent stack to prevent pressure changes.

Why Understanding Plumbing Terms Matters for Bay Area Homeowners

Whether you own a historic Craftsman in Willow Glen, a mid-century modern in Eichler, or a new construction home in Milpitas, knowing these terms helps you:

• Communicate clearly with plumbers about your issues
• Make informed decisions about repairs and replacements
• Understand estimates and know what you’re paying for
• Maintain your home more effectively
• Avoid unnecessary repairs by understanding what’s really needed

At Drain and Water, we’re committed to transparency. We’ll always explain what we’re doing and why, using language you can understand. No jargon, no confusion—just honest, professional service.