The video’s subject is a handyman who was working underneath an apartment’s bathroom sink to repair a small leak. He did not shut off the water first, though, because doing so would involve shutting down the whole apartment building.
Unfortunately, something went wrong with the attempted repair. 90 PSI of hot water began shooting ferociously out from under the cabinet! The main water shut-off valve was under lock and key, so the 14 minute video chronicles many frantic and futile attempts at stopping the leak live while the entire apartment gets flooded.
This nightmarish plumbing incident caught on camera vividly highlights the importance of having working, accessible shut-off valves in one’s plumbing system and knowing how to use them properly.
We’ve created a couple of YouTube videos on how to shut off the water at the home’s water meter and at the home’s primary valve box. While this is a good place to start, there are a few more crucial questions that must be answered in order to be well-equipped as a homeowner.
In this article, we’ll go over all of the important details about shut off valve location and use.
Shut off valve location is partly dictated by plumbing code and partly by whatever construction practices are conventional in your area. In the North Dallas cities where we work (like Frisco, Plano, Mckinney, Allen, etc…) the majority of houses were built between the mid 1970s and the early 2000s. Although construction practices certainly evolved over that time, plumbing valve location has remained largely consistent.
There will actually be two main shut off valves at the typical suburban residence. One valve will be at the city water meter (usually located in a buried box near the street). This city valve is usually under a locked lid, but with commonly available tools it can be accessed and shut off in the event of an emergency.
This will shut off the water to the entire property – including any yard sprinkler system and fire suppression system. Although, some larger properties have a separate meter for the irrigation system.
By plumbing code, a main shut off valve is also required near where the main water supply comes into the house. This is the valve designed for the homeowner to use and have easy access to. By shutting off this valve, just the house water system will be turned off – not the separate irrigation system or conventional fire suppression system.
Most commonly in our area, this valve is located in the front flower bed where the water supply pipe (which is buried in the yard) goes underneath the slab foundation to the first “manifold”. Or, in newer homes, the main shut off valve may be located behind a wall panel in the garage or in a utility room.
In areas with higher pressure, a special valve called PRV (Pressure Reducing Valve) is installed next to the main shut off valve.
Know where this valve is, make sure it is in good working condition, and have all occupants of the home practice shutting off the water in the event of a plumbing emergency to prevent damage to the home. This valve will either be a lever-handle ball valve or a round-handle gate valve (more on these later).
A shut off valve is required, by plumbing code, to be installed on the cold water supply pipe to the water heater (the top right-hand side when facing the water heater). Since this valve supplies water to the water heater, by shutting it off you will also be shutting off the water to all of the hot water pipes throughout the rest of the home.
This valve will also either be a ball valve or a gate valve. Typical practice in our area is for this valve to connect to a flexible supply pipe that attaches to the inlet pipe on top of the water heater.
Because the typical water heater has an average life-expectancy of about 10-12 years in our area, many people opt to install some sort of automatic shut off valve as well. This valve has a sensor which detects water if there is a leak and automatically turns the water off.
Another type of shut off valve that it is important to be aware of is the PEX manifold system.
Most newer homes (2010+) are plumbed with a type of flexible plastic pipe called PEX. One of the ways this piping is installed is by running a bunch of smaller pipes to the fixtures throughout the home from a single point called a manifold. Think about it like an electrical breaker panel for your water system. At this one central point there are a bunch of smaller shut off valves that you can operate to shut off the water to every bathroom/fixture in the house.
These can be a little touchy when they haven’t been used for a long time. Their all-plastic and o-ring construction doesn’t corrode, but o-rings have a tendency to become stiff and leaky over time. If these individual valves start to leak, they can often be rebuilt with new replacement parts from the manufacturer. The most common one in use around here is manufactured by Viega.
For typical residential toilets, there will just be one shut off valve for the cold water pipe supplying the toilet with water.
Typical practice for the “rough-in” dimensions is to locate this valve about 6” to the left of the centerline of the toilet (when facing the wall). It will come out of the wall about 6”-8” inches off of the floor.
This valve will either be a quarter-turn “stop” or a multi-turn “stop”. More about the differences between these two valve styles later.
Every bathroom sink will have two shut off valves – one for the hot water, one for the cold. You’ll see these small shut off valves right where the water pipes come out of the wall inside the sink cabinets.
These valves will connect to the underside of the faucet with flexible supply lines. These days, the supply lines are made out of rubber with a braided steel reinforcing sheath. Older valves often used ⅜” soft copper as the supply lines. These copper tubes were connected to the valves either with a compression nut and ferrule or soldered directly to the valves.
The “rough-in” dimensions vary quite a bit from one faucet to the next. But as a general rule, the hot valve will be 4”-6” to the left of the drain pipe, and the cold valve will be 4”-6” to the right of the drain pipe when facing the wall. Both of these valves will be slightly above or slightly below the drain pipe.
Under kitchen sinks, there will typically be three shut off valves. The two uppermost valves will be the hot and cold valves for the sink faucet. The lower valve is for the dishwasher.
Conventionally, these valves would connect to the faucet in the same way as bathroom valves/faucets with replaceable supply lines. Many newer kitchen faucets now come with integrated supply lines that connect directly to the ⅜” outlet of the valves.
In larger, newer homes, you may find an additional valve designed to feed an under-sink water filter or instant hot water tap.
The common rough-in dimensions are very similar to bathroom faucets with the hot valve ideally being on the left side of the drain pipe when facing the wall and the cold valve being on the right side. Of course, there is usually much more space under the kitchen sink, so you will often see these valves in various places.
The third and lowest valve under the kitchen sink is typically a hot water valve for the dishwasher located to either the right or left hand side of the kitchen cabinet.
You will frequently find this valve directly below the hot valve for the kitchen sink faucet. The supply line that connects to it (either ⅜” soft copper or braided steel sheathed rubber) will run horizontally along the bottom of the cabinet and go behind the dishwasher through a hole in the side of the cabinet.
If your refrigerator has an ice maker or filtered water spigot, then it will typically be supplied by a cold water shut off valve behind the refrigerator. This valve is traditionally located in a recessed, open-front plastic box.
When the valves have to be replaced, sometimes it can be done inside the box itself. Other times, some of the drywall directly below the valve has to be removed to access the pipe lower down.
In some larger homes with built-in refrigerators (like some of the Sub-Zero models), the shut off valve may be located in an adjacent cabinet or underneath the kitchen sink due to the refrigerator being too large to readily move by hand.
The clothes washing machine hot and cold water supply valves are typically located in a recessed box directly behind the washer. This box, commonly called a “washer box” also contains the indirect waste drain pipe for the washer’s wastewater discharge hose.
Some of these valves screw into threaded adapters that are located in the box itself. This means that the valves can be replaced without having to remove any sheetrock. Many of the newer boxes have valves that connect to the pipe below the box. This means that replacement required the removal of some sheetrock below the box.
The older style valves were multi-turn angle valves that shut off with a rubber washer. Newer style valves have a little lever handle that operates a ball-style valve instead.
Outdoor hose faucets typically won’t have a separate shut off valve just for them. They are screwed directly into a threaded fitting that is attached to the pipe in the wall. This means the water must be shut off to the house in order to make repairs or replace these faucets.
Newer hose faucets are called “frostproof faucets” because they are long in design and shut off back inside the wall where it is less likely to freeze. Older hose faucets would almost be identical to washing machine multi-turn valves and would operate with an internal rubber washer.
There is one interesting quirk/feature about common construction practices in this area. If there is a hose faucet located close to the main water shut off valve in the front flower bed, there may be a separate, smaller valve in the “water box” that controls just this hose faucet.
Like outdoor hose faucets, shower and tub valves generally have all of the plumbing hidden inside the wall.
Unless there is an access panel in the wall, there is typically no way to shut off the water for just these fixtures. In order to perform repairs like replacing the cartridge, the water will need to be shut off for the entire house. There is an exception to this, though.
Many of the newer shower valve designs do have built-in shut off valves for service. You can check for these by removing the handle and decorative trim plate to expose the valve body in the wall. If there are integral “stops”, then they will look like small slots on either side of the valve that can be turned with a flat-bladed screwdriver.
Going through this list of where different shut off valves are located reveals that there are a handful of different valve designs common in the typical residential home. They all operate differently and are prone to different problems, so it is important to be able to tell them apart.
We’re going to go over ball valves, gate valves, and different types of fixture shut off valves or “angle stops”.
Plumbers in different parts of the country often have different jargon for various parts of the house’s plumbing systems, but in the North Texas area, the individual fixture shut off valves are often called “angle stops” because they usually direct the water in a 90 degree angle as it passes through the valve. There are variations of these designs that allow water to pass straight through. These are called “straight stops”.
Full-port ball valves are the preferred standard these days in residential construction when it comes to main line shut off valves or water heater valves. These larger ball valves operate in much the same way as the smaller fixture shut off valve variety. By turning the handle clockwise 90 degrees, it turns the orientation of the internal ball and cuts off the water.
Although very reliable, these valves are not without problems. If the valves are made from a cheap brass alloy that has a high zinc content, a type of corrosion called ‘dezincification’ can occur. This allows water to slowly weep through the brass itself and you will notice crusty/powdery white buildup all over the valve.
Sometimes, water can leak through the seal of the stem that connects the handle of the valve to the internal ball. When this happens, you’ll notice drips of water coming from right underneath the handle. Sometimes this can be resolved by removing the handle and tightening down the “packing nut” underneath. This will tighten up the seal around the stem.
If the handle part itself has rusted off, you can attempt to grab the stem with a pair of pliers and turn it that way, being careful not to use excessive force. Just be aware that the handle of a ball valve usually has a protrusion that stops the ball at the right orientation. Without the handle, it is possible to turn the ball valve too far and actually open the valve back up again. Make sure that you are only turning the stem 90 degrees.
Before ball valves became dominant, plumbers used full-port gate valves instead. These were used for the main house shut off valves and for water heater supply valves.
Similar to the multi-turn angle stops, these gate valve handles must be turned clockwise many times before the water shuts off. They don’t use a rubber washer, though. Instead, turning the handle lowers a “gate” down into the path of the water – eventually sealing it off completely.
The problem with these older gate valves is that they tend to be very unreliable after not being used for a long time. Corrosion and sediment builds up in the path of the gate, and it can easily get stuck. Also, the brass stems that operate the gates tend to deteriorate over time and break off when you’re trying to operate the valve.
Bottom line, if you have an old gate valve that hasn’t been operated in a long time, it is best to not try operating it unless you’re prepared to replace it right away if it starts leaking or gets stuck in the off position. A safer bet would be to shut the water off to the entire property at the municipal water meter.
If you do attempt to operate an older gate valve for any reason, be sure to turn the handle slowly and gently. Avoid excessive force. If the handle starts to get hard to turn, back it all the way off in the reverse direction and try again. You may have to do this several times as the corrosion and deposits break off inside the valve and clear the way for the gate.
Now we come to small fixture supply shut off valves (or “stops”). The older, traditional design of these shut off valves uses a rubber washer that is twisted down inside the valve to shut the water off. We call these “multi-turn” style valves because the handle has to be twisted clockwise several times before the water fully shuts off.
When you turn the handle of an older style valve, it doesn’t have a hard stop at 90 degrees. After rotating several times, there is an increasing resistance for the last half-turn as the rubber washer squeezes shut.
If you are trying to operate an older multiturn style shut off valve under a sink or behind a toilet, there are several common things that can go wrong. The first is a leak developing at the stem. There is a seal that keeps water from leaking out around the round handle stem. If the valve is operated after a long period of inactivity, sometimes a drip develops where that seal is. If this happens, it can often be resolved by tightening the “packing nut” directly behind the handle.
Another thing that can go wrong is that the rubber washer may be too deteriorated to function properly. Some older washers get very brittle with age. As a result, when they are squeezed to shut off the water, they actually fracture and break up into little pieces.
When the water is turned back on again, the little chunks of rubber can travel up the supply pipes and clog up the faucet. If you suddenly notice a drop in pressure at your faucet after operating one of these valves, this is probably why. The aerator or other components of the faucet will need to be taken apart and cleaned to restore full flow out of that faucet.
When in doubt, it is often best to leave these valves untouched until they can be replaced. Unfortunately, many of them also come with corrugated, integrated supply lines that cannot be replaced. If this is the case, it is highly recommended to replace these valves when you are replacing the faucet.
Most newer style shut off valves are ball valves or “quarter turn” valves. Instead of a rubber washer that stops the water inside the valve, there is a polished, smooth metal ball that spins inside of a plastic shell.
When the ball is oriented in one way, water flows through smoothly. When the ball is turned 90 degrees, it stops the water completely. Although sometimes the hands can look similar, there is a clear difference when operating the valve. When you turn the handle of a ball style valve, the resistance remains about the same until it stops completely.
While more reliable than the multi turn valves, these valves can still fail, especially when they are not used frequently and the water is very hard (like in the North DFW area). The most common failure is that the “ball” will get stuck and break free from the stem. You will be able to turn the handle back and forth, but the valve will not operate.
In this area, there were many newer tract homes built with a novel type of push/pull shut off valve with all-plastic construction. Most of these are made by a company called Accor Technologies.
These are push-to-connect valves, which means that they are installed without any tools. An O-ring is what seals the valve to the pipe, and stainless steel grip rings are what hold the valve onto the pipe. In these ways, they are very similar to other push-to-connect fittings like those made by SharkBite.
Unlike SharkBite fittings, however, they are cheaper to purchase in bulk due to the all-plastic construction. They either have plastic ⅜” threads for connecting traditional supply lines, or they have integrated supply lines that cannot be replaced.
They also turn on and off in a unique manner. Instead of rotating a knob or lever, they have a round push/pull knob. The knob is pulled out to shut the water off and it is pushed in to turn the water back on. This is a very short movement, and the handle pops into place when it is either on or off.
Because of the novel mechanism, these valves can sometimes turn off on their own if there is high water pressure or water hammer present. They can also leak from the seam where the integral supply line connects or from the connection point to the pipe. We recommend replacing these valves when changing out the faucet.
Another more recent and novel type of shut off valve you will see in north Texas homes is a ball valve that comes in a recessed plastic box. This is often called a “pull stop“.
The box comes with a couple of pieces of plastic trim. In the center, there is a hole for the supply line to go through. Next to this hole there is a little plastic knob that attaches to the handle of the valve. This knob is pulled out to shut the valve off and pushed in to turn the valve back on.
The trim has to be removed to replace the supply line. If it stops working, the valve itself can be replaced. It must be that specific brand, though, or the entire plastic box will need to be replaced.
Outside of these differences, everything said about standard quarter turn fixture valves applies to these as well.
After finding and learning about all of the different valves in your house, there are a few maintenance tips and principles that will help you be prepared.
Plumbing doesn’t like to NOT be used for a long time; valves are no exception. When valves are left dormant for years and years, calcium deposits build up inside of the valve body and prevent it from working properly.
If your valves are in good condition, get into a habit of shutting them off and turning them back on once or twice a year. This will help break up any calcium that is developing and also allow you to inspect them for external signs of corrosion.
When you’re “exercising” your valves, it’s a good time to test them too. Open up a faucet(s) that is downstream of the valve and let all the pressure bleed down. After the faucet stops dripping, watch it for a couple of minutes to make sure the water has stopped completely.
The last thing you want is to find out your shut off valves don’t shut off all the way when mere minutes of a catastrophic water leak can cause thousands of dollars in damage to your home.
If you have an older home full of valves that have been untouched in years, then you may think twice about testing or exercising those valves unless you are ready to replace them right away if they fail.
Make sure you have some way of shutting off the water to your home (like at the main house valve), and regularly check the old valves for leaking or visible signs of corrosion. If you see these, plan on having the valve replaced ASAP.
If there are no visible issues, you can either have the shut off valves replaced individually when you have faucets/toilets replaced. Or you can plan a time to have them all changed out proactively.
If your main house valve is buried/inaccessible or is an old gate valve, we recommend prioritizing that and replacing it proactively with a newly rebuilt water box and ball valve. This way, any resident of the home can quickly access it and easily shut the water off to the home without any tools in the event of a plumbing emergency.
While water alarms and water-detecting valves (like FloodStop) have been around for quite some time, many new products are coming into the market that use smart technology to detect leaks in the home. Some of the leaders in this industry are Flo by Moen and Phyn.
Whether you choose a “smart” solution or just go with old-school water alarms, it is wise to invest in some sort of protection for any high risk areas of the home.
One of these locations is typically the water heater. Due to all of the water connections and their oft-hidden locations, water heaters are a leading cause of water damage in this area.
Another common location is under the kitchen sink and dishwasher. There are many drain and water connections here – especially if an accessory like an RO water filter or instant-hot tap is present.
If you have questions about any of your shut off valves or need them to be replaced, we would be happy to help! Our plumbers replace all different kinds of valves daily throughout the North DFW metroplex and have seen every possible type and challenging installation scenario.
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