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I'm a little OCD when it comes to traveling. I have learned from experience that when I am away, I constantly have visions that a pipe in the wall had burst and that the water is slowly filling the house. Having been through this enough times, I am tempted to put my worries to rest by simply turning off the main water line (in the garage) before we leave. My new fear with doing this, of course, is that I will cause something else bad to happen.

So I am curious, is it bad to turn off the water and drain the pipes prior to leaving for a week? In addition, what other precautions should I take aside from turning down the water heater? A few details - our house is two story, copper pipes, and we would be traveling in the spring time so temperatures in the house would stay at around 70 F.

T James
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12 Answers12

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Nothing bad should happen and it's not an irrational thing to do.

Turn the main valve slowly (both when turning off and on) to avoid possible water hammer effect that could stress pipe connections.

For the same reason, turn taps in the house on slowly when bleeding air after you turn the main supply back on. Start from the taps lowest down and closest to the main valve and work your way away and up.

IP cameras are a cheap way to keep an eye on your house while you're away for extended periods. I use old android phones with an app that sends alerts for sound and movement, it really helps with peace of mind and enjoying vacations.

bobs12
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You need to turn off the hot water heater if you shut off the water. The reason is the heat will keep the system mildly pressurized. If you have a leak it can slowly push all the water out, and then your water heater is running dry - bad!

Do feel free to shut off your water. That is fine, and the system will stay pressurized unless you have a faucet drip somewhere. I have seen houses hold pressure for months. If a faucet is opened or a leak happens, this pressure will drive out only a tiny amount of water - probably a few tablespoons, no more than a few quarts if a pipe drains.

In fact, closing the main valve from time to time will actually help you keep that valve in working order. If it is never shut off for 20 years, it will scale up and will not shut off fully, drippity-dripping water into the system when you're trying to solder a pipe. Very annoying. In the event of a pipe leak, that drippity-drip could let gallons (though not thousands of gallons). You test for this by closing the main valve, opening a faucet to release pressure from the system, and after the initial burst, see if it starts dripping again.

I would not worry about depressurizing a system damaging the pipes. That is a concern for high pressure boilers, in fact they tried to slow the cooling on Fukushima unit 1 by turning the passive cooling system on and off. When the batteries failed, they thought it was "on" and did not send a man to hike up to the roof to check the valve position. So the unit failed much sooner than expected, destroying their ability to save the other units. But for a nail... But I digress. If your pipes are so fragile that they're damaged by depressurization, they would have already failed from the pressure pulses of ordinary use.

Harper - Reinstate Monica
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By all means turn off the water, but try it first a week before you leave. If the old valve hasn't been turned in a while, it could fail in ways you don't want to deal with when you're catching a flight.

Gas water heaters (in my experience) have a "pilot" setting. Saves gas, makes it easy to turn back on without having to relight the pilot.

But double check: will anyone be in the place while you're away? House-sitter? Cat-sitter? Plant-sitter? Will they need to draw water? Flush a toilet?

CCTO
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Turing off the water is a good plan just in case and will not harm the plumbing system. Though as another member states, starting up again requires a little gentle patience.

However, if you do so I recommend you also remember to turn off your water heater and water softener if you have one. Actually, you should do this ANYWAY, just in case the city has to turn off your water to repair a main or some such.

If the water does drain out, maybe washer hose blows, you do NOT want the heater turning on.

The water softener needs water pressure to work properly and can become clogged with salt or sediment if it tries to cycle without a fresh supply of pressurized water.

BTW: You also want to go round and unplug electrical things. Most modern devices, like your TV for instance, are never REALLY off unless you physically disconnected from the mains, either by switch or pulling the plug.

It's a good plan to make up a written checklist that reminds you of what to turn off and in what order with a reciprocal checklist to power back up again. Also familiarize your significant other with the procedure and where all the taps, plugs and switches are and how to use them... just in case, god forbid, you are not there when they return...

Trevor_G
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There are arguments both ways, and a lot depends in your confidence re the integrity of the pipes, the likelihood of a power outage, etc.

But what I have done on a couple of occasions (when I knew there was some questionable plumbing in place) is turn the water ALMOST all the way off, such that opening a faucet would result in a slow trickle. This reduces (but does not eliminate) the hazards from a burst pipe, etc, while avoiding most of the other negatives of turning the water all the way off.

Hot Licks
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If you're turning off the main valve, I'd leave at least one tap open. This way, if pressure rises or falls in the pipes owing to temperature changes, the system is open to the atmosphere. Normally (in standard US/Canada plumbing) the system can "push back" on the water main pressure, but if you close that valve, it can't.

(Some cities use a strategy of high-pressure mains, and install regulators at each home. These are effectively backflow preventers, and in such homes, an expansion tank may need to be installed, to handle normal pressure fluctuations within the house. If you've got one of those, ignore my advice.)

Whatever tap you leave open, make sure it's one that cannot siphon water back into the system. This is really only a risk if you've got a hose or extender on it that could fall into standing water; any tap that's well above the rim level of its sink is fine. Don't choose an outdoor tap to leave open, as debris or bugs could enter the system.

CCTO
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Turn off the water; don't bother draining the pipes. Turn down the water heater if you feel like it. Nothing bad will come of it, and you'll feel better.

You didn't ask, but I'll mention that washing machine hoses are frequent offenders with respect to flooding. Most people suggest you change them every 5 years or so.

Aloysius Defenestrate
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Even if you don't turn off the main valve, you should shut off the water to the washing machine (and dishwasher, if you have one). Those are connected with [rubber] hoses, which are far more likely to fail than the copper or PVC pipes used for the rest of the plumbing.

AndyB
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You can still have massive flooding even if you turn the main water off. How you ask? We left our air conditioner set to 80 while away one week in the summer (We live in Texas). Unfortunately, a blockage of mold/mildew built up in the condensation drain line, which then overflowed into the sink that the condensation line drains into. The sink overflowed onto the floor in the upstairs bathroom and much damage ensued. Poor bleach down the drain/vent tubing as recommended to prevent this, and perhaps again before leaving for vacation to minimize this risk, or suffer our fate you might!

gyeamans
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Would a water pressure regulator between the water main and your house be a solution or at least help your peace of mind? My office has been known to infrequently flood, usually on the weekends due to pressure increases on the weekend. After I had one installed, the problem has not reoccured.

anomieman
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My sister and her husband left their second/vacation home 2 years ago and the toilet continued to run. It resulted in a $600.00 water bill. They always turn the water off at the main now and have not had further problems.

Barb
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Do you have an automated sprinkler system?

To add to the answers already, yes turn off the water, but keep in mind what things require water in the meantime and plan accordingly. If you have a sprinkler system that waters your lawn, it will not get water. Think about whether that will be acceptable for the length of time you are gone.

imagineerThat
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