What is the purpose of a main shut-off valve?

Author: Dr. Arnaldo Senger DVM  |  Last update: Friday, December 8, 2023

A water shut-off is a primary control that turns off the water supply to your bathroom and kitchen plumbing. For example, it prevents flooding when you are planning to repair a fixture such as a faucet or toilet or when you are faced with a plumbing emergency, like a leak from a water heater or supply line.

Is it OK to shut off the main water valve?

It is perfectly safe to turn it off by either turning the wheel clockwise or closing the lever. If you don't know where to locate the valve, you may find it: In the basement. In the crawl space.

Why are there two main water shut off valves?

Main Water Shut-Off Valve Basics and Importance

Most homes actually have two such valves: One for outside water sources, which is generally controlled by the city you live in, plus one for your indoor plumbing and water areas.

What is the main water shut-off valve called?

Gate Valve:

Gate valves are one of the most common valves used as a main shut off valve. They are reliable and long-lasting. Gate valves have a twist-type handle and should only be used to fully open water supply or completely shut off water supply.

How long do main water shut off valves last?

Generally speaking, most water shut-off valves last between 10 to 20 years. However, they can last longer, depending on the material you choose. For example, brass valves can last about eight to 10 years, while stainless steel can last over 30 years.

Shutoff valve basics

How long should water run after turning off main valve?

After all faucets are open, let the COLD WATER run for at least 30 minutes. During this time, also flush each toilet in your home 2 or 3 times.

Why won't my main water shut-off valve turn off water?

Fixing a Stuck Water Shut Off Valve

We recommend putting a cloth over the handle and using your hand to slowly rock the stuck valve back and forth to loosen it. Keep doing this until the valve can be completely opened and closed. If the valve won't turn after trying this, grab a pair of Channellock pliers.

Should my main water valve be fully open?

A rotary gate valve should be opened to the stop and then closed just a little. By leaving the valve just a bit closed, the stem packing is not compressed. This extends the life of the valve, and makes it easier to operate when it needs to be closed fully. A quarter-turn ball valve can be left fully open.

How many main water valves does a house have?

Every home has two main water shutoff valves: one inside the house and the other by where your property meets the street. The simplest way to shut off all water running through your house is to know where the main valve is located inside your house.

Does shutting off main water affect water heater?

There are many circumstances in which the main water supply is turned off. When this happens, many homeowners wonder if it's safe to keep the water heater on of it should be shut down too. In most cases, it may not be necessary to turn off the water heater, but it also won't hurt, either.

Should I turn off main water valve before vacation?

To prevent damage to your home, it is advisable to turn off the main shut-off valve before going on a vacation. You can find the main valve in the basement, crawlspaces, concrete slab, or the attic.

When should I replace my main shut-off valve?

It's important for every homeowner to know that most homes come with compression valves which are not designed to last. The compression aspect of the valve usually fails to work after about 8-10 years. This usually fails either with wear and tear or simply because it's old and has been in the home for a long time.

What does the outside water shut-off valve look like?

The gate shutoff valve is round and shaped like a wheel. To close, turn the shut-off valve clockwise until it's firmly closed. The ball valve has a lever handle, and to close it, you turn the handle one-quarter clockwise until it's tightly closed.

Why does water valve leak when turned off?

Loose packing nuts on the water shut-off valve are known to cause the leaking and in certain circumstances, the washers might malfunction due to an accumulation of mineral deposits on them.

Does shut-off valve affect water pressure?

Replacement may be necessary if the valve has failed or broken. 2. Check the main shut-off valve. This valve can influence water pressure, even if it has been turned slightly.

How often should water main valves be exercised?

Valves affecting hospitals, schools, and valves on water mains of diameter 16-inches or greater should be given priority, and should be exercised/assessed once per year.

Will shutting off water keep pipes from freezing?

To prevent pipes from freezing, the best thing to do is turn your water off if you can locate your valve. If not, leaving your faucets on with a slight trickle - not a drip - to prevent broken pipes, he says.

Why is water dirty after shut off?

Discolored water and trapped air are common occurrences after a water main break or other water system maintenance work. Discolored water is caused by sediment and mineral deposits in the pipes that can be stirred up when the water is turned off and then back on following work on WSSC Water's water system.

How many turns does it take to turn off water main?

How to close the main valve (Shut-off/Turn-off) Round “wheel” handle valves will turn off by turning the handle clockwise. It may take two or more full revolutions.

Can a shut-off valve burst?

Some older homes will have a gate valve, which will have a small metal wheel, also usually red, which you turn to close the valve. If your home has a gate valve as the main shut off, be careful, as these can break easily. It's best to have it replaced with a modern ball valve as soon as possible.

How long does it take to replace main water valve?

If the valve is easy to access, then it typically takes an hour or two to replace. However, if it's tucked behind cabinetry or other barriers, it can take several hours since the barriers will first need to be removed then reinstalled after replacing the valve.

Previous article
What color white should I use on my ceiling?
Next article
Is brushed nickel good quality?