One factor would depend on if you live in a cold climate. If you do, and you shut off the main valve, and you don’t completely drain out the system, it can freeze up if your heating fails. Some people actually let a faucet or tub valve drip while away in order to prevent the likelyhood of this happening.
Also, of course, if your home is heated by a boiler, obviously shutting off the main will also cause the boiler to dysfunction….and could cause a hazardous low water problem with it if you don’t have a cut-off sensor plumbed in.
If you do decide to do this, you will also need to consider all other appliances in your home that use/depend on water supply, such as water heater, etc. These must be cut off at the energy source (gas cock or breaker depending on if electric or gas, reason I say this is depending on the appliance, a dangerous situation may be possible if water source is cut but energy source is not) and preferably drained out (to prevent freezing if applicable as well as for sanitary reasons).
Once you have considered all factors involved and have taken measures to satisfy them and you are comfortable with then shutting the main off it’s up to you, but ordinarily, unless it’s for an extreme period of time, I’d recommend against it really. Ask a friend or co-worker to simply check in on your home from time to time instead.
» This message has been edited by AKPlumber on 08 January 2005