Water control valve type (C) Carson Dunlop Associates Plumbing System Controls & Valves
Guide to all types of controls used on plumbing systems

  • PLUMBING CONTROLS & VALVES - CONTENTS: Description of common stop valves used on plumbing water supply piping. Drain valves installed on water heaters, water tanks, heating boilers etc. 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.
  • POST a QUESTION or READ FAQs about plumbing system valve types & applications
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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 include stop valves, boiler drains, fuel valves, check valves, foot valves, etc. - just about every type of control valve used in residential buildings is defined and illustrated here.

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

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

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

As Carson Dunlop Associates' illustrations below show, a broken water control valve stem can obstruct or block water flow through the valve. Globe valves (below left) 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.

Water control valve type (C) Carson Dunlop Associates Water control valve type (C) Carson Dunlop Associates Water control valve type (C) Carson Dunlop Associates

[Click to enlarge any image]

Also see SHUTOFF VALVE LOCATION, USE for a discussion of how to find, use, & repair building water supply shutoff valves and stop valves.

Drain Valves: boilers, water heaters, water pressure tanks

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.



Plumbing & Heating Controls Valves, Service Valves, Safety Valves

Hot water tank control valves Carson Dunlop Associates

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.

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:

We have a water break tank in basement cant get overflow out.We have been told we can drop a over flow from the large tank into a smaller header tank.

A flow detector is then place in the smaller tank and then connected to the incomming water main via a solenoid valve which would turn off water supply. Any ideas where I can purchase solenoid-operated water shut-off valves?


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.

Watch out: check the solenoid valve specifications carefully to match against your system's needs, including at least the following:

  1. Suitability for handling the liquid you are controlling
  2. Operating pressure range of the solenoid water valve
  3. Operating voltage ranges of the solenoid valve: for example low-voltage 12VAC, 12VDC, 18VAC, 24VAC, or household current levels of 120VAC 50/60Hz ot 208-240VAC 50.60 Hz
  4. Valve default position: normally OPEN or normally CLOSED
  5. Use of lead in the valve components - may be unsuitable for some locations or may be prohibited by local plumbing codes

Where to Buy Electrically Operated or Solenoid Operated Water Control Valves

InspectAPedia is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information provided free to the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.

Other Electrical & Solenoid Valves used in Buildings & on Building Mechanical Systems

Examples of other 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.

Other Plumbing System Control Valves

Check valve (C) D Friedman

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

Urinal with flushometer valve (C) D FriedmanI 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?

What 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 & completyely 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 the More Reading links or topic ARTICLE INDEX shown below.




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PLUMBING CONTROLS & VALVES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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