Water control valve type (C) Carson Dunlop Associates Plumbing System Controls & Valves
Index to all types of plumbing valves & controls

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Plumbing valves guide:

This article describes and illustrate the different types of valves found on water supply and drainage systems as well as plumbing fixture valves and on other plumbing and heating devices & fixtures.

We discuss the definitions of globe valves, gate valves, and ball valves, the properties of drain valves installed on water heaters, water tanks, heating boilers etc. . We describe stop valves, boiler drains, fuel valves, check valves, foot valves, etc.

This list of the types of control valves found in residential and light commercial buildings includes links to more-detailed information about each valve type.

We explain stop valves installed at plumbing fixtures. Gas and oil piping fuel line stop and control valves & check valves. Links to details about all types of plumbing system valves on supply piping, drain piping, & plumbing fixtures or appliances: check valves, flushometer valves, etc.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Types of Plumbing Valves Used on Water Piping: Globe Valve, Gate Valve, Ball Valve Compared

Globe type stop valve (C) Daniel Friedman Gate valve (C) Daniel Friedman Ball valve used on gas lines (C) Daniel Friedman

Descriptions of all common stop valves used on plumbing water supply piping are given here.

Above we illustrate the three most-common types of valves used in plumbing, a globe valve, a gate valve, and a ball valve, each shown in a partly-open position.

The yellow handle on the ball valve tells us that this valve is approved for use on gas piping installations. We're showing these valves in a partly-open position to make the valve mechanism more-obvious. But only the globe type stop valve is intended to be left at settings between fully open and fully shut.

Here we use Carson Dunlop Associates' sketches and our own photographs to define and explain the differences in design and intended of a globe valve, a gate valve, and a ball valve in plumbing applications.

Article Index

Globe Valves for Water Flow & On/Off Control

Water control valve type (C) Carson Dunlop AssociatesDefinition: Globe valves provide easier regulation of water flow but use a washer and valve seat that must be maintained and that can fail from corrosion or pitting.

Because of the complex valve passage through which water passes in a globe valve there is some water pressure (or flow rate) drop across the valve when it is open.

[Click to enlarge any image]

Globe valves (sketch above) tend to most restrict water flow compared with the gate valve (center) and ball valve (right). But a broken stem on a gate valve can also leave the valve stuck partly or even fully closed (or open), regardless of how you may be able to turn the valve handle.

Globe valves are often used as water shutoff valves on heating boilers, at outdoor hose bibbs or sillcocks, at water pressure tanks, clothes washer connections, and water heaters (calorifiers, cylinders, geysers).

Globe type valves are also used in a smaller form as fixture shutoff valves at sinks and toilets. Globe valves at fixtures are usually referred-to as stop valves.

Oatey gate valve washing machine hookup at

Our photo above shows a pair of round-handled valves in a washing machine hookup provided by Oatey™. From the small body size of the valve I think these are probably globe valves.

Below is a globe valve used as a sill-cock or outdoor "hose bibb" for connecting a garden hose.

Sill cock or hose bibb valve (C) Daniel Friedman

However you may find any of the three water control valves described here installed at a variety of fixtures.

Gate Valves for Water On/Off Control

Water control valve type (C) Carson Dunlop Associates

Definition: Gate valves (sketch just above) are intended to be used in the fully-open or fully-closed position, that is, they are not good for regulating water flow through the valve.

The metal-to-metal seal of a gate valve is also subject to failure from corrosion, and on occasion we have found gate valves with a broken stem that left the valve stuck open or closed.

The user turns the handle and thinks he is changing the valve position but with a broken valve stem the gate does not move.

Ball Valves Used for Water Flow & On/Off Control

Ball valve for sale at a Home Depot store (C) Daniel Friedman Water control valve type (C) Carson Dunlop Associates

Definition of a Ball Valve

Ball valves (photo & sketch above) are also a type of gate valve but these controls use a spherical ball type gate with a hole bored through the ball. Turning the handle rotates the ball gate to open or close the valve.

Ball valves, like traditional gate valves, are intended to be left fully open (water on) or fully-closed (water off). Ball valves are also used on gas piping systems.

Watch out: Of the three plumbing valve types described here, only ball-valves are provided in models rated for use on gas piping. Ball valves intended for use on LPG or NPG gas piping will have a yellow handle and will bear a tag giving the valve's listing approval.

Photograph of a water pressure tank air valve, relief valve and main water shutoff

The white arrow in our photograph above shows a ball valve serving as the main water shutoff control on a water supply system.

You can usually spot a ball valve by its distinctive lever-type handle. When the ball-valve lever-type handle is set parallel to the water pipe the valve is in the open position - as in our photo above.

Gate valves of the traditional gate valve design and the ball valve design both permit water flow through the valve without pressure drop.

Oatey washing machine connections using ball valves (C)

If you can see into the opening of a water control valve you can usually determine what type of valve it is. Above we see into the openings of a washing machine hook-up provided by Oatey™. You can see the shiny stainless steel sphere marking these as ball valves.

These special ball valves can be moved from fully-open to fully-closed in just 1/4 turn, especially useful where space is limited..

You may also have noticed the red and blue lever type handles that are characteristic of ball valves. With the washing machine hookup ball valve handle turned across the valve outlet the valve is in the closed position.

L-Port & T-Valves: Design, Usage, Features

T-valve three way ball valve applications & uses (C)
What is a T-valve and what is an L-valve and how are they used?

Above, a T-valve that is used to switch flow between two different output destinations. [Click to enlarge any image]

Typical T-valves such as the Mondeo T-valve shown above, are ball-valves used to divert flow from a primary input source to one of two different destinations. The ball of the valve is drilled straight through and then an intersecting drill opening is made at a 90 degree angle to the first passage.

Ball valves are intended to be used in the fully-open or fully closed position. For a T-valve that means you'd send all of its output to one of two possible destinations. These valves are not usually intended to be used to send output to two destinations simultaneously.

Drain Valves: boilers, water heaters, water pressure tanks

Boiler drain on a Weil McLain oil fired boiler (C) Daniel Friedman Replacement boiler drain valve (C) Daniel Friedman

Water heater drain valve (C) Daniel Friedman

Photograph of a water pressure tank air valve

Watch out: Often an unused or rarely-used plumbing valve may be stuck, may have lost an internal washer, and may otherwise fail to close properly if you touch it.

We advise against attempting to open or adjust heating equipment drain valves unless you are prepared to shut down the system and install a replacement valve in the event of a leaky valve that can't be shut off.

Fuel Valves: oil & gas piping in buildings

Fusible link oil line valve (C) Daniel Friedman

Plumbing & Plumbing Fixture Valves

Oatey washing machine control valves

Typically at a sink or toilet the water supply is controlled by a local stop valve.

Thanks to Carson Dunlop Associates, a Toronto Home Inspection Firm and Home Inspection Educator, for permission to use sketches shown in this article



Electric Solenoid Operated Gas, Oil, Water Valves used in Buildings

Here we describe electrically operated plumbing valves used for water control of equipment or piping in buildings.

Reader Question: where can I buy a solenoid-operated water shut-off valve?

15 January 2015 Martin said:

... Any ideas where I can purchase solenoid-operated water shut-off valves?

This question and our reply were posted originally at WATER TANK: USES, TROUBLESHOOTING.


Martin a number of companies provide electrically-operated solenoid-type shutoff valves including valves that can close off a water supply line. The operating pressure range and piping diameters among the various products vary so you’ll want to contact the company’s technical or sales people to discuss your specific needs.

Prices for electric solenoid valves range from under $50. U.S.D. to over $500. U.S.D. depending on the application.

See ELECTRIC SOLENOID VALVES for a detailed list of electric solenoid controlled valve manufacturers and vendors.

List of Types of Electrical & Solenoid Valves used in Buildings & on Building Mechanical Systems

Examples of types of electrically operated or solenoid operated valves used in buildings include

Our complete list of types of control valves use in buildings and on building mechanical systems is found at MORE READING.

Radiator Valves

Radiator valve with air bleeder (C) Daniel Friedman


Saddle Valves or T-Puncture-Valves

Saddle valve, adapted from Wikipedia 2018/01/11 original source: valves, also referred to as piercing valves or puncture valves, have been used to add low-flow water connections to refrigerator ice makers, humidifiers, and other appliances.

The saddle valve shown above, adapted from a Wikipedia illustration, has a plastic tube attached, perhaps feeding an ice maker. - Retrieved 2018/01/11 original source

The valve body clamps onto an existing copper water pipe.

When the valve's T-handle is turned down a pointed end on the valve gate pierces the copper piping.

When the valve is backed open water can flow into tubing attached to the saddle valve outlet.

In our OPINION these valves, though convenient, do not work reliably if the valve must be frequently opened or closed.

Watch out: saddle valves are prohibited by some plumbing codes in some jurisdictions such as the U.S. Florida Plumbing Code, the Virginia Plumbing Code, and the 2009 IPC. Other plumbing codes do not explicitly approve the use of saddle valves but do not mention them by name.

2009 International Plumbing Code & Virginia Plumbing Code

605.9 Prohibited joints and connections. The following types ofjoints and connections shall be prohibited:

1. Cement or concrete joints.

2. Joints made with fittings not approved for the specific installation.

3. Solvent-cementjoints between different types of plastic pipe.

4. Saddle-type fittings.

707.1 Prohibited joints. The following types of joints and connections shall be prohibited:

1. Cement or concrete joints.

2. Mastic or hot-pour bituminousjoints.

3. Joints made with fittings not approved for the specific installation.

4. Joints between different diameter pipes made with elastomeric rolling O-rings.

5. Solvent-cementjoints between different types of plastic pipe.

6. Saddle-type fittings.

Plumbing Code Examples Prohibiting Saddle Valves

Other Plumbing System Control Valves, Check Valves, Faucets, Foot Valves, Water Shutoffs

Check valve © D Friedman at

Reader Question: Installing a pressurized system & Flushometer Valve Toilets & Urinals on a Well & Pump Water Supply System

Urinal with flushometer valve © D Friedman at I have a well system at a marina and would like to install commercial flushometer toilets and urinals. It is old and is currently served by a standard residential system.

I have space above the rest rooms and would like to install a stand alone pressurized system that is fed by the existing residential system, but would provide the gpm and pressure to function the commercial units. Likely to be a total of 3 toilets and two urinals.

Any ideas or plans available? Thanks, Bill

Reply: Be sure that your well water supply system, pressure tank, pressure, and water supply piping diameter & flow rate can support flushometer valves; consider waterless urinal fixtures.

Bill, there is no technical reason why one could not install flushometer type toilets and urinals at a property served by a standard pump and well system, but the cost and trouble may be more than first meets the eye.

Where we find flushometer type toilets and urinals installed it's usually at a building served by municipal water supply and employing larger diameter water supply piping than the 1/2" pipe usually found at residential type properties.

That's because flushometer fixtures, relying on both water pressure and total gpm flow rate to work properly, need a higher pressure and total flow rate than most residential systems deliver

You can achieve the necessary pressure and water quantity for the fixtures by adding a water tank and pump at a suitable location, but you might need also to install larger diameter water supply piping to each fixture.

Details about flushometer valves and their installation, troubleshooting, diagnosis and repair are now found at FLUSHOMETER VALVES for TOILETS URINALS.

Reader Question: what's the purpose of the inline float valve at the top of an electric water heater? Can I remove it?

Hot water tank control valves Carson Dunlop AssociatesWhat is purpose of & is it necessary ? In- line ball- cock valve in water entry line going into top of electric water heater. Would it be ok to eliminate line containing floating ball ? It sticks & completely restricts my hot water flow. - Randall Doran

Reply: thermosiphon prevention device?


I'm guessing from your description that you are describing an anti-siphon valve at the top of your water heater. The valve is intended to prevent hot water from circulating up into the building water supply piping by "gravity" (warm or hot water, being less dense than cold water, will naturally rise up out of a hot water tank into cooler water in building piping).

If that's what you've got you could remove the valve but the result might be wasted energy - sending hot water out into building piping (where it will cool off) when no hot water is being drawn at a plumbing fixture.

In general you could eliminate a control valve feeding water into your water heater, but it will make it impossible to turn off "hot" water in the building when service or repair to the heater is needed - you'll instead have to turn off water to the whole building.

Watch out: An improperly installed shutoff valve on a water heater can be very dangerous, risking an explosion. Usually the "hot water tank shutoff valve" is installed only on the cold water pipe coming into the water tank. There should be no shutoff valve installed on the hot water line leaving the water tank.


We discuss details about water heater controls at OIL FIRED WATER HEATERS.


Continue reading at BACKFLOW PREVENTER VALVE, HEATING SYS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see FAUCETS, OUTDOOR HOSE BIBBS - and faucet leak repair procedures


Or see this

Index to Types of Plumbing & Heating Controls Valves, Service Valves, Safety Valves

Our Carson Dunlop Associates sketch (above/left) illustrates a gas fired water heater - the heater's drain valve, often made of plastic, is shown at the bottom right in this illustration.

Watch out: do not touch, open, or otherwise manipulate relief valves on heating equipment unless you are prepared, should the valve leak, to shut down the heater and replace the leaky valve immediately.

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