HARD FREEZE PREP: Should i shut off the main in a vacant rental house?

[DoctorBuzz]

I'm sure the answer is yes... but after blowing out all the water from within the lines, right?

I had both hot and cold water dripping very slowly when it dropped below 30 a few weeks ago.. in the kitchen and bathroom, as I'm not 100% as to which is father from the main.

As for this hard freeze that's going to last a week, i turned all 3 faucets (adding tub faucet this time) to a steady stream, PLUS plugged the hot water heater in, but the central heat is still off. I still forgot to let the outside faucets drip, however... Which could've been a mistake.

But how bad could it've gotten if i just turned the main off and turned all faucets (including outside ones) wide open? .. without using a compressor to empty it, obviously? Really don't like the idea of hand the house winning water for a week at these temps!!

 

[DoctorBuzz]

OK... no responses yet?? Let's try this another way....

Let's say there *is* water in the line. I shut off the main, and I leave all the faucets closed (or off, whatever)! As the water freezes, there will be pressure that could bust a weak connection in the pipes, no? This is like a closed Coke can in the freezer.... it's going to explode!!

But what if, instead, the only difference was that I opened ALL the faucets...so that the water freezes in the pipes. Since there's no pressure... no explosion, right?? This would be like a full, but open coke can.... just ice but no explosion.

Am I thinking about this the right way??

EDIT: Found this --> http://disastersafety.org/wp-content/uploads/Freezing-Bursting-Pipes_IBHS.pdf

Doesn't answer my question directly... but makes a valid point that pressure could build up between some "ice blockage" and ANY closed valve, which would be the main in my case. Soo... same problem, just in reverse of normal.

 

[CT-18]

I am not sure this is a direct answer. Some pipes freeze and don't split and some don't freeze at all.

 

[voletl]

The answer is yes blow out the lines with an air compressor you'd be surprised how much water is still in your pipes even if you leave the faucets open the water will still freeze and the water will still expand and it will still burst your pipes