Some things in life are worth learning before it’s
too late—like the locations of your water and gas shutoff valves. Now
granted, these shutoff valves are often hidden in some dark, creepy corner of
the house. But if a water pipe springs a leak, knowing where the shutoff valve
is could save you thousands in water damage repairs. What’s more, you
can’t make those major plumbing repairs or improvements unless you first
turn off the water. The same goes for turning off the gas—though with
some strict safety precautions, which we’ll talk about
later.
Home water and gas systems contain two types of shutoff
valves:
main or
master shutoff valves for stopping the flow of
gas or water 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 story contains a lot of
“oftens,” “usuallys” and “almost
always’s.” 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.
Here
are the basics of each system.
Gas Shutoff Valves
Houses with natural gas have a main shutoff valve (Fig. A)
located just before the gas meter. This valve, often called the street-side
valve, is normally a rectangular nub (Photo 1). 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.
The street-side main shutoff valve must be opened and
closed with a wrench, and, truth be told, gas companies don’t want you
operating this valve; they only want their own employees, plumbing and heating
contractors and fire department personnel to use it. They’d rather you
use the
house-side main shutoff valve located
after the meter (Photo 2). This
house-side 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
iron pipe is transporting the gas, it’s often black; this differentiates
it from similar-shaped, gray galvanized water pipe.
FIG. A: Typical Gas System
Click image to enlarge.
If your home is newer and you find a flexible copper pipe
running from the meter into your utility room, you probably have a higher
pressure gas system. In this case, your inside main shutoff valve (Photo 3) 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.
Well, don’t just sit there; get up and locate those
valves! Then tag ’em as we explain in
Fig. B.
In addition to the house-side main shutoff valve,
individual gas appliances should have a service or appliance shutoff valve
(Fig. A) that’s immediately accessible, in the same room and within 6 ft.
of the appliance. These valves allow you to stop the flow of gas to your dryer,
oven, furnace, water heater or gas fireplaces to make repairs or new
installations without cutting off gas to your entire home. Most service valves
are single-lever ball valves; again, handle parallel to the line means gas is
flowing, perpendicular means it’s cut off. On dryers and ranges, this
valve is usually hidden behind them and can only be reached by sliding the
appliance out from the wall. This service valve will usually be 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. When you repair
or replace a gas appliance, use these shutoff valves to stop the flow of gas.
(Most pros replace the flexible connector when they replace the appliance.) If
you discover you have a faulty supply valve, or your system doesn’t have
one, turn off the gas using the houseside main shutoff valve.
For those with propane or liquefied petroleum gas,
there’s 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. Sometimes you
need to use a pliers to free the stuck handle.
Important! Now that you know
where your gas valves are, also 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. If you’re working near the main
or individual gas valve and clearly know the source of the gas leak and that
gas hasn’t been leaking for long, shut off the valve and get out. But if
you’re uncertain of the source or how long the gas has been leaking,
clear yourself and your family out and call the gas company or fire department
from a neighbor’s house (not your own—remember, phones can generate
sparks!). Always err on the side of caution.
Shutoff Tag
FIG. B
Click image to enlarge.
FIG. C: Typical Warm-Weather Water System
Click image to enlarge.
Also note: When you shut off
main or individual gas valves, you’ll be extinguishing the pilot lights
to 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
Almost all water meters have one main shutoff valve
directly before the meter and another directly after (Photo 5). Where the meter is located depends on
the climate in your area.
In cold climates (Fig. D),
the meter and main shutoff valves are located inside, usually in a basement or
other warm area to prevent freezing. In milder climates (Fig. C), the meter and its two shutoff valves
may be attached to an exterior wall or nestled in an underground box with a
removable lid. Between the water main in the street and the meter,
there’s also usually a buried
curb stop
valve (accessible only by city workers wielding special long-handled
wrenches) and a
corporation
stop, where your house water line hooks up to the water main. Your
city absolutely doesn’t want you messing around with these last two
valves. They prefer you turn your water off or on using the main valve on the
house
side of the meter. This valve will normally be a gate-type valve,
with a round knurled handle, requiring several full clockwise rotations to turn
off. In newer homes, it could be a ball valve.
In addition, most houses built today have small, localized
shutoff valves called
fixture
supply stops (Photo 6) installed on the supply lines leading to
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 at toilets if at all. This can lead to great family
discord, since working on a single drippy faucet can require shutting off water
to the entire house at the main valve, leaving everyone showerless, flushless
and waterless. With supply valves, you can turn off the water to a single
fixture while fixing or replacing that faucet. If your plumbing system lacks
supply stops, install them when you shut off the main valve to repair a sink,
toilet or appliance. Eventually
you’ll have supply stops at every fixture, and your family won’t
yell at you every time they see you with a wrench in your hand. Remember,
fixture supply stops must be easily accessible; you can’t drywall or
plaster over them without installing an access panel to reach
them.
Supply Stop Problems
Be aware of these common problems with fixture supply
stops:
Many water supply valves drip when turned off and then
back on again after an extended period of disuse. To fix a drippy supply valve,
try gently tightening the packing nut (Photo 6)
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—which will require shutting off the main
valve.
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. If the water trapped
between the spigot and supply shutoff valve freezes, it can burst that section
of pipe. Since there’s no water flowing through this short damaged
section of pipe, there are no obvious leaks or sign of damage—yet. But
when you turn the supply valve back on in the spring and pressure returns to
that pipe, the burst section of pipe will leak like crazy—and often go
unnoticed for hours or days. One plumber told me he’s made dozens of
repairs dealing with this mistake.
FIG. D: Typical Cold-Weather Water
System
Click image to enlarge.
Finally, many icemakers 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 (Photo 4). 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.
