Re: IMPT Information on Frozen Pipes
From: Gerald Manata (
Date: Sat, 11 Jan 2014 11:26:15 -0800 (PST)

On Saturday, January 11, 2014 10:34 AM, Sharon Villines <sharon [at]> wrote:

Below is an excerpt from a NYTimes article on frozen pipes, why they freeze, 
how they burst, and why leaving a faucet running is important. The reality is 
counter intuitive and I had not a clue. We had a huge flood at Takoma Village 
this week and missed an element that would have helped us slow the water flow 
while we located someone who knew how to turn of the water to that pipe.

The first thing we should have done was to open the faucet outside to release 
water pressure in the pipe.

Since we all have pipes close to exterior walls, and some have pipes leading to 
outside faucets and they may or may not be insulated sufficiently for very 
sub-zero weather I thought is might be helpful to everyone. And it's 
well-written. And I hope worth the length.

Excerpt from the New York Times:

It helps to understand how pipes burst. The way that happens doesn’t follow 
conventional wisdom, which says water turns to ice and pushes outward against 
the wall of the pipe and causes a rupture. The blockage grows along the length 
of the pipe and acts like a piston, causing elevated water pressure when the 
faucet is turned off, and that’s what causes the rupture. So if you can relieve 
the pressure downstream of the blockage by allowing the tiniest little drip at 
the faucet, then the ice blockage can grow and it won’t rupture the pipe.

So when it gets really cold I should turn on every faucet in the house?

You can be strategic about it. If the water is being fed from the center of the 
house and you’re not abandoning your home, those pipes are O.K. But if a pipe 
goes into your crawl space, or if it’s close to an outside wall or especially a 
vent, it’s a real good candidate for bursting in really cold weather.

So if you’re concerned about your pipes possibly bursting and you have a faucet 
with a gearshift lever, when you turn it on so it trickles, make sure it’s warm 
water so you’re getting both the hot and cold. If you run it overnight on a 
cold night and lose a quart of water, nobody will complain.

The trickling-water idea is obviously for when I have good reason to think 
those pipes are in danger. If I insulate those pipes, I can breathe a little 
easier, right?

Yes, but a poor pipe insulation job is worse than no insulation. If you’re 
going to insulate, don’t leave blank spots, especially at elbows and T’s, where 
pipes can be more vulnerable to freezing. And make sure all the fittings are 
insulated as well. There are also thermostat-controlled heating cables you can 
buy at the hardware store.

You want to hear something really juicy?

Nope. Well, O.K. Go.

Ask a plumber whether hot or cold pipes burst more frequently, and they’ll all 
tell you it’s the hot water pipe.

And that’s because . . .

They’ll give you a whole bunch of different answers, but the real answer is the 
toilet. The guts of a standard toilet actually function as a pressure-relief 
device. If the water pressure rises in the pipes, the ball cock allows a drip 
of water to leak out into the tank. Hot water systems don’t have anything like 
that, so they’re more at risk.

What if I forget one faucet in the house and I wake up and no water comes out 
of it when I turn it on, but the pipe hasn’t blown yet?

O.K., here’s an important thing. If that happens, it’s critical not to close 
the faucet. Ice has created a blockage and it’s still growing toward the 
fixture. If you shut the faucet, there’s nowhere for the pressure to go, and it 
can burst. If you leave it open, even slightly, you’re O.K.

And then what? Grab a propane torch and pray I don’t burn down my house while 
I’m warming up the pipes?

I wouldn’t recommend anything stronger than a hair dryer. And the nice thing 
about leaving the faucet open is that you can hear it running once you’ve got 
it going again.

Are there any areas other than crawl spaces and exterior walls where I should 
inspect the pipes more carefully?

The hose bibb.

I’m not sure I know what that is.

The thing you hook up the hose to on the outside of the house. If cold 
weather’s coming, make sure there are no hoses attached, or they can do a real 
number on the house. With the newer style of bibb, if the hose is attached, you 
have water in the cold part of the wall, rather than air. This is much more a 
problem with new frost-protected hose bibbs, because people think 
frost-protected means they can leave the hose attached, and that’s a big 

And be aware of cracks or gaps where cold air might come in and hit a pipe. Get 
a few cans of foam insulation and look for things that are really cold, then 
try to foam every gap or seam in that area so the cold air isn’t leaking on the 

It usually takes more than cold temperatures to freeze a pipe. More typically 
you need really cold temperatures, and cold wind blowing on it. There’s a lot 
of forgiveness in a plumbing system. Just don’t say that to someone whose pipes 

Sharon Villines
Takoma Village Cohousing, Washington DC

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