Know your shutoff valves and keep your home safe from spills and leaks.
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Some things in life are worth learning before it’s too late—like the locations of your water shutoff valve and your gas shutoff valve. “One of the first things I show homeowners during a plumbing walkthrough is where all their shutoff valves are,” says long-time contractor Randal Fuller. “If a pipe bursts or a faucet won’t stop leaking, you need to be able to shut off the water immediately.”
Granted, these valves are often hidden in dark, creepy corners of the house, or maybe even underneath it, and who wants to go there? But if a water pipe or gas connection springs a leak, knowing where the shutoff valve is could save you thousands in water damage repairs and possibly even prevent a catastrophe.
What’s more, you can’t make major plumbing repairs or improvements unless you first turn off the water. The same goes for the gas, though some strict safety precautions exist. We’ll tell you all you need to know in this post.
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Main Shutoff Valve vs. Individual Ones
Home water and gas systems contain two types of shutoff valves: a main or master shutoff valve that stops gas or water flow to the entire house, and individual or supply shutoff valves for specific appliances and fixtures. We’ll look at both types and tell you how to identify them (since they often look similar), where they are and how to operate them.
You’ll notice this post uses many words like “often,” “usually” and “almost always.” That’s because valves vary greatly in location, shape and number, depending on the age of your house, the local codes and which part of the country you live in.
Gas Shutoff Valves
Street-side gas shutoff valve
Houses with natural gas have a main shutoff valve located just before the gas meter. This valve, often referred to as the street-side valve, is typically a rectangular knob. When the long side of the nub or handle is parallel to the incoming gas line, it’s open, and the gas is flowing. When it’s turned a quarter turn, perpendicular to the incoming pipe, it’s closed.
You need a wrench to open and close the street-side main shutoff valve, and, truth be told, gas companies don’t want you operating it; they only want their own employees, plumbing and heating contractors and fire department personnel to use it. They want homeowners to use the house-side main shutoff valve located after the meter.
House-side gas shutoff valve
The house-side shutoff valve—usually a ball valve—may be located where the pipe first enters the house or farther down the line, but it will always be located before the first appliance. If an iron pipe is transporting the gas, it’s often black, which differentiates it from a similar-shaped, gray galvanized water pipe.
Valve for a higher-pressure natural gas system
If your home is newer and you find a flexible copper pipe running from the meter into your utility room, you probably have a high-pressure gas system. In this case, your inside main shutoff valve is probably near your furnace or water heater, just before it enters a flying saucer–shaped doodad called a pressure regulator. There’s also a chance your home—especially if it’s older—doesn’t have a house-side main shutoff valve.
- Pro tip: Hang the wrench that opens the gas meter supply pipe on a piece of stainless steel wire, then secure the bottom portion. Twist the wire just a few times so it’ll release quickly. This makes the valve easier to find, and you’ll be able to close it quickly in an emergency.
Service valves
In addition to the house-side main shutoff valve, each individual gas appliance should have an easily accessible service or appliance shutoff valve in the same room and within six feet of the appliance. This shutoff valve allows you to stop the flow of gas to the appliance—whether it’s a dryer, oven, furnace, water heater or gas fireplace—to make a repair or a new installation without cutting off gas to your entire home.
Most service valves are single-lever ball valves; again, a handle parallel to the line means gas is flowing, perpendicular means it’s cut off. This valve is usually hidden behind dryers and ranges and can only be reached by sliding the appliance out from the wall.
- Pro tip: Service valves are usually at the end of a fixed pipe and connected to a flexible supply pipe called an appliance connector. Take care not to kink or pinch this flexible pipe.
Propane: If your home uses propane or liquefied petroleum gas, you’ll find a main shutoff valve on the tank itself, and usually a main shutoff valve somewhere before the first appliance.
Some valves (both gas and water) manufactured before 1980 contain a lubricant to help the valve seal better and operate more smoothly. In many cases, this lubricant will have hardened or reacted with the gas to make the valve difficult to turn. Applying gentle heat with a hair dryer and working the valve open and shut in stages will usually free it up again. You may need to use pliers to free the stuck handle.
Figure A: Typical Gas System
This illustration shows how gas is brought into the house from the street. You can find a larger version of this image in the Additional Information.
Figure B: Gas System Inside the House
This illustration shows how gas is delivered in the house. Once you’ve located your main shutoff valves, label them. You can find a larger version of this image in the Additional Information.
Safety Measures
Be careful with gas!
Now that you know where your gas valves are, know this: It’s not always safe for you to turn these valves off in an emergency. When gas reaches a certain concentration in a room or house, the slightest spark can set off a tremendous explosion. A light switch or telephone—even static electricity from your clothes—can produce such a spark.
“When it comes to gas,” says Fuller, “I always tell people: if you’re not 100 percent sure, don’t touch it. If you smell gas or suspect a leak, get out of the house and call your utility company or fire department. Even if you’re just trying to disconnect an appliance, like a stove, it’s best to call a licensed professional. Natural gas is nothing to mess around with—it’s flammable, and an incorrect connection can create a dangerous situation.”
- Stay in the know: If you have natural gas in your home, be sure you know the signs of a gas leak and what to do in case of an emergency.
Be prepared for emergencies
It’s a good idea to prepare for gas emergencies before they happen because sometimes projects involving gas lines don’t go as planned. When a gas project goes bad, that’s not the time to search for the right tool to shut the gas off at the meter. A good strategy is to buy an emergency gas meter wrench shutoff tool and secure it to the meter as described above. You can pick one up at a home center for about $12.
- Pro tip: When you shut off the main or individual gas valves, you’ll be extinguishing the pilot lights of certain appliances. Many newer appliances have “pilot light–less” electronic ignition systems, but if you have older appliances, you’ll need to relight the pilot lights. Most appliances have clear relighting directions on a label near the pilot light or in the instruction manual. But some pilots are pretty darn hard to reach. If you’re uncomfortable with relighting the pilot light, hire a plumber or call your local gas service company.
Water Shutoff Valves
Main water supply valve
Almost all water meters have a main shutoff valve just before the meter and another just after. The meter’s location depends on your area’s climate.
In cold climates, the meter and main shutoff valves are located inside to prevent freezing. In milder climates, the meter and its two shutoff valves may be attached to an exterior wall or nestled in an underground box with a removable lid.
Water shutoff valve appearance
The valve on the right in this photo is an older street-side main shutoff, while the one on the left is the house-side main shutoff. In newer homes, these will probably be ball valves.
Each fixture should have a shutoff valve
Most houses built today have small, localized shutoff valves called fixture supply stops installed on the supply lines for toilets, faucets, dishwashers, washing machines, water softeners and water heaters. These supply stops usually have a small round or oval handle that you turn clockwise two to four full turns to shut off the flow of water. Many older homes have them only in the toilets, if at all.
These valves prevent family discord. Without them, you’d have to shut off water to the entire house at the main valve to work on a single drippy faucet. That leaves everyone shower-less, flush-less and waterless. With an individual shutoff valve, you can turn off the water to a single fixture while fixing or replacing it.
If your plumbing system lacks supply stops, a good time to install them is when you shut off the main valve to make a repair. The goal is to have supply stops at every fixture.
- Pro tip: Fixture supply stops must be easily accessible; you can’t drywall or plaster over them without installing an access panel to reach them.
Fixture supply stop problems
Be aware of these common problems with fixture supply stops:
- Dripping: Many water supply valves drip when turned off and then back on again after an extended period of disuse. To fix this, try gently tightening the packing nut with a wrench or opening and shutting the valve several times until the drip stops. If a supply valve simply won’t stop leaking, your only option is to replace it.
- Freezing: In cold climates, most people remember to close the supply shutoffs for their outdoor spigots to prevent freezing, but many then forget to open the outside spigot to drain the remaining water. Water trapped between the spigot and supply shutoff valve can freeze and burst that section of pipe. Since no water is flowing through this short, damaged section of pipe, you won’t see obvious leaks or signs of damage until you turn the supply valve back on in the spring. When pressure returns to that pipe, the burst section will leak like crazy, and that leak may go unnoticed for hours or days.
Saddle valves: Many ice makers and furnace humidifiers are fed by small flexible copper tubes that are connected to larger copper pipes via a very small T-handled device called a saddle valve. These valves essentially bite into the larger pipe to feed the smaller one.
Leaky saddle valves are a major cause of residential water damage and are no longer code-compliant in many areas. If you have saddle valves, replace them with standard supply stops.
Figure C: Typical Warm-Weather Water System
This illustration shows how water comes into the house in warm climates. You can find a larger version of this image in the Additional Information.
Figure D: Typical Cold-Weather Water System
This illustration shows how water comes into the house in cold climates. You can find a larger version of this image in the Additional Information.
Additional Information
- Figure A: Typical Gas System
- Figure B: Gas System Inside the House
- Figure C: Water system for warm climates
- Figure D: Water system for cold climates
FAQ
Should I regularly test or inspect these valves?
Yes, says Fuller. “Every few months, I give each shutoff valve a gentle turn just to make sure it’s not stuck. Valves that sit for years without being touched can seize up or corrode, and when you actually need to use them, they won’t budge.”
Can I turn off the gas to individual appliances?
Codes require every gas appliance to have its own shutoff valve. You can use this to turn off the gas to the appliance. If you have an appliance without a shutoff valve, you have to turn off the gas supply for the entire house before servicing it.
About the Expert
- Randal Fuller is a contractor with more than 40 years of experience. He owns Fuller Services, a full-service HVAC, plumbing and electrical company based in northern Alabama.
