Main building water shut-off valve:
How to turn off the building water supply. This article explains how to find the main water shutoff valve in a building and how to turn the building municipal water supply off. We also illustrate typical outdoor and indoor municipal and well water shutoff valves and explain their use.
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If your water supply is by private pump and well and you need to turn off the water, details are at WATER SHUTOFF VALVE, WELL PUMP.
The articles at this website will answer most questions about freeze protection for piping and other building plumbing and heating system components: how to winterize a building to avoid frozen pipes, and how to thaw frozen water supply & drain piping, wells, & water tanks.
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As Carson Dunlop Associates point out in the Home Reference Book, the main shut-off valve controls all the house water. The valve should be readily accessible and easy to operate.
Some main shut-off valves have bleed valves to drain the system once the valve is closed. Some of these bleed valves can be shut off, although others discharge automatically, as the main valve is closed.
This discharge of water can be disconcerting if one is not familiar with the bleed valve function.
Inaccessible main water shutoff - you have to be able to turn off water in an emergency to avoid costly building flooding and damage
Leaking main water shutoff valve - should be repaired or replaced
Partly-closed main water shutoff valve - may result in poor building water pressure or flow.
Inoperative main water shutoff valve - is perhaps the most common problem: Since these valves are not used regularly, it is common for them to be stiff. They often leak when operated. If you cannot turn the main shutoff valve with a modest force, don't force it - if you break the valve a horrible plumbing leak may ensue. For this reason, they are not tested during a home inspection. Try turning the valve in the opposite direction gently to see if you can free the valve.
Turning water off: Turning the main water shutoff valve "down" or "in" or "clockwise" or "to the right" (rightie tightie) closes the valve - turns off the water.
Turning water on: Turning the main water shutoff valve "up" or "out" or "counterclockwise" or "to the left" (leftie loosie) opens the valve - turns on the water supply.
Readers should also see FREEZE-PROOF A BUILDING for an explanation of how to protect a building from leaks, water damage, or freezing pipe problems.
Just turn off the water supply to your building at the main water shutoff valve. You can usually find this valve on the water pipe just inside the building where piping enters the structure.
Our sketch above shows the main water shutoff valve in a building served by municipal water supply.
Our photo (left) shows a main water shutoff valve - the red handle in the center of the photo just before the water meter. Incidentally, you can see a lead water supply pipe entering the structure to the left of this valve.
The main water shutoff valve inside of a building served by municipal water is usually found between where the water pipes enter the building (left side of the photo above) and the water meter.
But especially on older homes whose original main water valve may have become stuck or leaky, you might find one or even more "main" water shutoff valves installed simply by following the entering water pipe to its first branch point (where typically water splits off into the cold water supply and hot water heating system).
Sometimes we can get a "stuck" main water valve working again by slightly loosening the cap nut around the valve stem - just a half turn - and by placing a few drops of light-weight oil on the valve stem.
Do not force the main water shutoff valve if you cannot make it turn with just modest force. Call an experienced plumber for help instead. If you break the water shutoff valve you may cause a building flood.
Emergency water turn off procedures - municipal water supply: if it's an emergency you may be able to have your plumber or municipal water supply company turn off water to the building at an outside water shutoff or "curb cock" on the property or at the street (see below). If you find this step necessary, while that outdoor valve has turned off water to the building it's exactly the right time to have a professional install a new high-quality, reliable indoor water shutoff valve for the property.
In some cities or towns that provide municipal water supply to buildings, an outdoor water main shutoff valve will be found between the street and the building,marked by a large valve, often embossed "water". (Photo, above left.)
Our photo (above, left) shows an outdoor main water shutoff valve on the Vassar College Campus in Poughkeepsie, New York - an area of freezing weather. Shown is just the valve handle, below which a long iron rod extends to the actual valve itself. In this case the installer thoughtfully painted the valve blue so it could be easily found in the grass, and s/he kept the installation low enough above ground level that the valve will not be damaged by mowing.
Our second main water shutoff valve photograph (above) shows the actual main water valve, below ground, during installation. In some areas not exposed to freezing weather, such as Southern Arizona, an outdoor main water shutoff valve may be located in a below-ground box near the street (photo at left). You may find that the water meter is located in this same compartment.
Don't mess with the outdoor water main shutoff valve unless it's in an emergency such as a burst incoming water pipe inside the building which the leak is before the indoor main water shutoff valve (the piping to the left of the red handled valve in our above photo of an indoor municipal water shutoff valve).
Your municipal water company employees will have and use a special T-wrench to turn this outdoor valve in order to open or shut the outdoor water main buried below.
Details about turning off water when the source is a private well and pump system are at WATER SHUTOFF VALVE, WELL PUMP. An excerpt is below.
Usually the main water valve is between the water tank and the rest of the building. So even if things freeze or a pipe breaks in the building, only the actual water in the pipes would leak - a minimal quantity.
Our photo (left) shows the main building water shutoff valve at a property served by a private well and water pressure tank.
For lever-type valves, when the valve handle is parallel to the piping the water is ON. When the valve handle is turned to a right angle to the piping the water supply is OFF.
For round handled water shutoff valves, turning the valve "in" or clockwise turns the water OFF and turning the valve "out" or counterclockwise turns the water ON.
Before moving on to the other Heat-On winterizing Steps (Winterize Water Softener & Treatment Equip. and Find & Fix Water Pipe Freeze-Up Points and Heat tapes, Heat, Insulation prevent Freeze-Up and Freeze Protect Drains) here are a few basic suggestions:
At FREEZE-PROOF A BUILDING we discussed property management basics like turning off and unplugging electrical items, notifying neighbors and insurance company, etc. You should also:
These and similar individual water supply valve turn-offs that you may identify reduce the chances of a flood in an unattended building should an individual fixture or pipe break during the winter.
Of course if you are turning the heat off for the winter, a different set of drain-down and other steps are needed, and are discussed beginning at Winterize- Heat Off Procedure.
This sketch of a gas-fired water heater and its control valves is provided courtesy of Carson Dunlop Associates.
Some building managers also open each plumbing fixture to remove pressure from the piping system. We don't go beyond this step in winterizing a building unless the building heat is to be left off. If heat is to be turned off and the building completely winterized, see the procedure at: Winterize- Heat Off.
We have a problem with our outside water main ball shut-off valve, it does not turn off the water in the house. Since the home lies approximately 20 degrees below the water company's main water valve, it might be that we have a similar problem our former owners had experienced. We would appreciate your opinion if it is possible that the pressure regulator valve, which the water company replaced in 2006 after a problem occurred, can cause the home's water main ball shut-off valve to fail/get damaged.
Today we saw that a truck from the water company up there next to our drive way released for 10 minutes a very high strong stream of water, which certainly looked like they tried to relieve water pressure in our neighborhood. In all of our six years living here we never had seen the water company do that, but when I asked the man doing it, he answered that they are just doing regular maintenance of flushing the pipes.
If there is the possibility that water pressure from above/the street can damage our water pressure regulator valve, which was replaced in 2006, and, maybe also our main water ball shut-off valve, we would like to know that in order to take appropriate steps of prevention for the future.
We appreciate in advance your expert response. - Seniors Chris and Noel
Your water truck driver's answer makes sense. Municipalities do flush water mains on occasion for various reasons such as having done work on the line and the need to flush out debris, or on occasion to assure that a water quality test is properly performed.
Flushing the line wouldn't change the delivery pressure in the municipal water system except during the brief interval that the line is being flushed. As soon as the municipal water line flushing operation stops, the water pressure in the water mains will return to its usual pressure. So flushing the water main also won't fix your balky or broken municipal water shutoff valve. It may need replacement.
May I please request your opinion about a problem we discovered a few days ago with our attempt to turn the water main ball valve outside our home off, because we wanted to repair something inside the house - a toilet.
The water did NOT turn off. Six years ago there was a problem with too high pressure outside this house and the water pressure valve was finally replaced by the water company.
Is it possible that the water main ball valve got damaged because the water pressure valve failed again?
Our home sits approximately 20 degrees below the water company’s water meter/main valve; there is quite a steep drive way before reaching our house main water shut-off ball valve.
I'm just speculating because we don't know the details of your installation. But if your water shutoff valve looks like the blue disc in our photo above (and discussed earlier on this page) then your municipal water shutoff valve is buried.
A steel shaft connects the ground level control to the buried valve. On occasion the shaft or its tip are damaged or disconnected. Unfortunately if turning the valve at ground level doesn't work, it will be necessary to excavate to find, diagnose, and fix the problem.
If your water shutoff valve is at ground level under a cover such as we show at left, you live in a climate where freezing is not a concern and the main water shutoff is at ground level too.
If this valve won't shut off the water:
You still need to have the broken main water shutoff fixed, but it will be less of an emergency if your toilet repair can go ahead.
You are getting a bit higher water pressure if your home is downhill from the main water supply line but that should not be the cause of a failed valve. If the valve was replaced recently and it's failed again, the replacement part (or its installation) could have been faulty.
When a recent repair part appears to have failed, when making the repair a second time we try to make sure that the new repair part is from a different source, brand, or manufacturing date in order to avoid the chances of getting a second defective part from the same manufacturing run.
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