Is this my main shutoff valve?

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Grebus

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Attached are pics of a copper water line (it was painted white) in my basement. It is on a wall that is directly across from the outside water meter at the street. I'm trying to figure out if this is the main shutoff valve for the house or if it is just on a line that feeds an outside spigot (is that a drain underneath the valve?). I don't really want to try the valve as it is old and will probably leak. The last picture is where the pipe comes through the other side of the wall, and then goes into a exterior wall under where my kitchen is on the upper floor. Thanks.
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Terry

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Does your home have oil heat? The pipe and fittings below look to be for oil.
The shutoff with the small drain may be a main valve if it's 3/4".
You can shut it off and find out very quickly. Regardless, the only way to know for sure is to try it.
 
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A stem valve has two states:

1. When it is closed, the rubber bibb washer sits against the seat. If either washer or seat is corroded, you'll never be able to truely shut off your water supply, a trickle will always flow thru it. You will never see this leak externally.
2. When it is opened, the stem packing wraps around the stem. If this material has gone bad, you will see it leak externally.
 
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Grebus

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Yes, the house used to have oil heat, but was at some point converted to gas and the oil tank was abandoned.

The outside diameter of the copper pipe is about 7/8". The other thing I noticed is I can hear water running through the pipe in the last picture when someone is showering or flushes a toilet on the opposite side of the house. Would that indicate that this is likely the main supply pipe rather than a branch off to the kitchen?

If I try the valve and it ends up leaking, do I tighten the packing nut to try and stop it? Thanks again.
 

Terry

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"If I try the valve and it ends up leaking, do I tighten the packing nut to try and stop it? Thanks again."

Yes, normally just snugging the bonnet is all you do.
When we open valves, it's all the way open, and then back it down a bit. That way the next person can rock the valve back and forth and decide which way to turn the valve.
A fully closed valve, I've seen people almost tear it off the wall going the wrong direction.
It is most likely the main.
 

Smooky

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My guess is that it is a water line. Normally a ground is not attached to a gas or oil line. The shut off valve could just be for an outside faucet or it could be for the whole house. The little round knurled nut on the bottom of the valve is a drain. That type of valve is normally only in a water line so you can shut it off and drain the line to prevent it from freezing. You could shut the valve off and see what is affected. The smaller pipe below the valve that is attached to a larger pipe could be a gas line or not.
 

Grebus

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OK, thanks for the advice.

On another note, since being on this forum I discovered the ice maker line I hooked up 2 years ago, a Watts floodsafe, is a potential "un-safe" flood. Guess what was replaced today? Thanks again.
 
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