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.

Discussed here: Where to find the building municipal water shutoff valves. How to turn off water supply from community water systems.

When, where, how, and why to turn off water in a building to avoid freeze damage or simply to shut down a building that is not in use.

What else needs to be turned off, drained, or protected against freezing? How to fix a stuck or faulty main water shutoff valve.

How to turn off water in an emergency if the shutoff valve doesn't work.

Where & How To Turn Off the Building Water Supply

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.

[Click to enlarge any image]

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.

Common Problems with Main Shutoff Valves

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

If your water shutoff valve is not working and you need to install an emergency shutoff

see EMERGENCY WATER SHUTOFF VALVE - methods to stop water flow to permit repairs.

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.

Which Way to Turn the Main House Water Shutoff 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.

Where to Find & How to Turn Off Water in buildings Served by Municipal Water Supply

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).

What if the Main Water Shutoff Valve is Stuck

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.

How to Turn Off the Water in buildings with a Private Well and Water Pump - Which Way to Turn the Water Shutoff Valve

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.

Guide to Turning Off Other Plumbing Fixtures in a Winterized "Heat-On" Building

Before moving on to the other Heat-On winterizing Steps note that we have a series of detailed articles on freeze-proofing - here are just a few of them:

• DRAIN FREEZE PROTECTION
• HEAT SOURCES to AVOID FROZEN PIPES
• PIPE FREEZE-UP POINTS
• WATER SOFTENER / TREATMENT TURN OFF

Below 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:

• Turn off water supply to outside faucets
• Turn off water supply in to the water heater
• Turn off the valves on the washing machine hot and cold water supply hoses
• Turn off water supply to humidifiers, ice makers, or similar equipment

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.

This sketch of a gas-fired water heater and its control valves is provided courtesy of Carson Dunlop Associates, a Toronto home inspection, education & report writing tool company [ carsondunlop.com ].

Additional Optional Steps to Turn Off Building Water to Protect from Freezing

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 suggestions beginning

at WINTERIZE - HEAT OFF PROCEDURE

How to Repair a Stuck or Faulty Main Water Shut-off Valve

Reader Question: Our Main Water Shutoff Has Failed? Flushing the Water Line vs. Relieving Pressure

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

Reply: Flushing a municipal water supply line won't change its normal operating pressure

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.

Reader Question: Our Outside Municipal Water Shutoff Seems Not to Work

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.
- Chris.

Reply: The shutoff valve may need replacement, but first check that the ground-surface control is actually connected to the 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:

• First make sure that you are accessing the correct valve and not your neighbor's valve.
• Second, sorry to say, if the valve handle turns but it's not shutting off water, then the stem or valve internal parts may be broken and the valve will need replacement.
• Before calling a plumber to repair the main water shutoff valve ( a repair that we do recommend), look at your house plumbing system. Chances are that you can find a cold water shutoff valve within the home that will shut off water to the toilet so that you can make that repair.

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.

How to Turn Off Water if the Valve Does Not Work - Emergency Shutoffs

This topic has moved to EMERGENCY WATER SHUTOFF VALVE

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-07-08 - by (mod) -

As my associate Mark Kramer would say, it depends.

You need the main water shut-off valve to be easily and readily accessible so that in an emergency such as a burst pipe you can quickly shut off water supply to the building. So if you live in a freezing climate where the control valve enclosure could fill with water and freeze solid you could have real trouble in an emergency.

Beyond readily accessibility the fact that develop is wet or even underwater is not normally a sanitation Hazard as the water flowing into your home should never be in contact with ground water at the valve or anywhere else.

If the valve is constantly flooded and underwater, condition for which it was not designed, you could have a corrosion problem that could make the valve difficult to operate when needed or even become Vicky. New paragraph. However occasional wedding and flooding would not be considered harmful.

So what's left is having to reach under possibly nasty water to find the valve in an emergency.

On 2020-07-08 by Nadine Morgan

Our water shut off valve in our newly constructed home is located outside & buried underground in a box in a shrub bed. The builder's rep showed it to us just after it had rained. The box was completely filled with water so much so that I couldn't see the valve.

Had to reach arm into the water & feel around for valve. Fact that box filled with water seens to me to be a problem.
Builder says it's not. Says it's typical when it rains. The same thing happens with the city water cut off valve. That box was flooded with water too. Is this a problem that builder should fix for house cut off valve? If so what do I recommend? House is located in St. John's, FL

On 2019-09-11 - by (mod) -

Greg

Thanks for sharing what I agree is a bit aggravating. In my OPINION responding to a weak water pressure complaint by saying that other people's pressure is worse is ... well what should we use to label such a remark? Rather thin?

Often debris stirred up during nearby work on water supply pipes or fixtures or valves can flow into and clog shower heads and faucet strainers. Those are usually cleared by un-screwing, cleaning, and replacing the part.

Other causes for loss of water pressure after new work on piping can be

- some dope pushed too-big a blob of solder into a soldered copper pipe joint or fitting (I've been that dope so I know this happens)

- someone installed a pressure-reducer or other device to deliberately reduce water flow rate and thus water usage as part of a water conservation measure (try installing a new shower head designed for lower flow rate)

Replacing a shower head does not normally require breaking open a wall. Shower heads SCREW on to the very end of a pipe, typically 1/2", that extends out from the wall.

But to be fair to your annoying super, it's always scary to offer to work on any old plumbing: pipes rust, corrode, break, leak, jam, or otherwise give a hell of a problem when they're disturbed after 90 years of sitting there. So the super knows that she may be opening a can of worms.

On 2019-09-11 by Greg

II have been in a 7-story prewar bldg (built in 1930) in NYC for 17+ years, on the second floor. Bathroom was retiled this spring, and water was shut off during the work. None of the faucets or showerhead were removed or replaced.

I always had great water pressure; when the water was turned back on, it was not at same level I'd had the previous 17 years. I asked the super to set it back to previous level; he said a couple of things:

One, that my pressure had been twice as much as anyone else's, and

two, that to fix it would require replacing the showerhead and that would necessitate breaking the wall (i.e., messing up the new work that had been done, which I know is not accurate; the water is weaker from the tub faucet too, plus it just doesn't make sense).

To get to my question: How is the water pressure controlled in a building like mine? Is there a setting at the site of the shut-off valve that needs to be opened more? Where would that be?

Thank you

On 2017-11-24 - by (mod) -

Right, that would indeed math the outside water shutoff

On 2017-11-23 by Dave

There's a shaft that goes over the main water valve that the city uses to turn on and off the water does that shaft come out of the ground d and how

On 2016-03-03 - by (mod) -

Use a pipe locating service to follow the water line from street to house. Look for an in-ground box or cover.

On 2016-03-03 9 by Frederick

Trying to locate under ground main valve

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