if any of you homeowners wake up to a bathroom or kitchen with a frozen water pipe, shut the water to that area if possible. a frozen pipe can split and will not leak until it thaws. so it is wise to shut the water to that area and to check it periodically.
if something is frozen and you have to leave the house to go to work or to go grocery shopping, shut the main until you come home.
hey, pipes freeze but that doesn't have to be a catistrophic event if you are careful when they thaw..

The problem is that pipes will not THAW if the water is turned off, they will only freeze harder and that can break the lines.

that may be true in phoenix but not on cape ann.
if the area with frozen pipe/s is heated to a much warmer temperature than 32F, why would they not THAW..
anyway, i would rather not risk a possible flood when they do thaw.

If the water system loses pressure, it takes less for the pipes to freeze. The same thing can happen to drinks left in cars.

if the pipes are already frozen, how does it lose pressure by shutting them off?
BTW, an open bottle of gin left in the trunk in the cold weather will freeze faster than unopened one?

They thaw by getting a "trickle of water" to come out of the faucet, then leaving it open as the trickle becomes a drip and then a faster drip, then a stream when the water breaks through the frozen section. If the valve is turned off, you create a closed system and the ice will increase, remember it EXPANDS when water freezes, and have nowhere to go except burst the pipe.



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quote; the pipes are already frozen, how does it lose pressure by shutting them off?

It DOESN'T. The pressure increases as the ice continues to form and expand.

quote: an open bottle of gin left in the trunk in the cold weather will freeze faster than unopened one?

I have no idea. On cold nights, (4F here last night) I let the faucets drip and never leave my gin in the trunk. I can't make martinis with frozen gin.

I even put on a sweater this morning before the sun came up.

Come on down I have Coronas and Pina Colada!

When I lived in Wisconsin a few years ago, when it got below -30 degrees we left the far faucet at just a drip which prevented many a freeze..

Sometimes I have to leave home for a week or two on work projects. Whenever I leave home in the winter, I set the water heater to "vacation", turn off the main valve at the street, open all the faucets and flush the toilet to lower the water pressure in the system. Is there still a danger of bursting pipes?

Yes. If there is water in the pipes at all, and the temperature where they are located stays below freezing for extended periods, then ice can and will form. You won't find out if you have a break until it thaws and you turn the water back on. Pipes don't always break when they freeze though. CPVC and copper are the most prone to breaking. Galvanized and pex are better survivors.

Yes, but not as much and no chance of a flood until you turn it back on.