Learn how to shut down your vacation home for the winter season to avoid big plumbing problems later. Get step-by-step instructions on how to drain a plumbing system.
LESLIE: Well, if you are lucky enough to own a vacation home , you know it’s a great investment and a wonderful place to get away, that you can actually call your own. But the unique thing about a second home is that it likely remains empty for half of the year or even more, making maintenance and care of it super-important.
TOM: And shutting down the home for the season, especially if it’s the winter season, has to be done just right to avoid big plumbing problems later. With us to talk about that is Richard Trethewey , the plumbing and heating contractor from TV’s This Old House .
RICHARD: Hi, guys.
TOM: Now, most people would think that draining a plumbing system  should be an easy thing to do. But a lot of people get it wrong and keep lots of plumbers very busy come spring.
RICHARD: Well, that’s right. Any water left in that pipe is going to freeze and break the pipe. And it won’t show up until the next spring when you turn the water back on. This, more than almost anything, is a function of how well the plumbing was done initially. Many vacation houses are done well so that you can open up one valve and all the water will just drain right out of all the main pipes, because they’ve been installed perfectly with no traps and no places where water can sit.
TOM: And conversely, many vacation homes were done poorly where they started off as being real bare-bones winter cabins and then plumbing was added to it, electricity was added to it and so on. So it never really had a comprehensive plan. And in those situations, you really have to be very, very careful to get every speck of water out of that.
RICHARD: Absolutely. So it starts by turning that water main  off. And now you’re going to say, “How do I get rid of this water?” So you can open up the draw-off somewhere in the building and drain the water out but that’s not going to guarantee that it all gets out of there. So probably the most effective way is to get an air compressor and to connect it with a double-ended hose to that compressor, again, to that outside sillcock or some faucet.
RICHARD: And then one by one, go along and open up – let that air pressure push all the water that could be trapped in elbows and T-fittings and push it right out. So that’s going to get most of it out but you still have other places where you have to watch out for.
LESLIE: Now, is this a necessity, draining the system, if you keep the house conditioned during the winter season but it’s unoccupied?
RICHARD: People worry about the risk. I’m a believer in leaving the house in the low-temperature state, not completely letting it go to an icebox and freeze. But people still – if they don’t winterize their plumbing , they still live with that fear that one pipe will split and run all the time. So, most people will feel much more comfortable to get that plumbing system drained out. They might leave the heating on low and a lot of times, the heating system might have a little antifreeze in it, as well.
TOM: Now, Richard, you mentioned blowing out the water with the compressor. What about the traps? What about the water that stays in on the drain side? Because the air compressor is only going to affect the supply pipes, correct?
RICHARD: That’s right, on the hot- and cold-water system. On the drain side, it’s a completely separate system. In that case, you have to put propylene glycol – non-toxic antifreeze, often used in the RV world or the marine world – and actually go into every trap and every place where water could sit in the drain system.
RICHARD: There’s some places that are obvious: underneath every sink, every kitchen sink, every lavatory. There’s some traps that are not obvious: underneath the bathtub; people forget that there’s one under there. And also, the toilet itself is a trap; it’s integrally built into the bowl. And putting a little bit of that antifreeze into the toilet tank itself, lifting the cover, is also a good …
TOM: Now, are there any other places we may have missed?
RICHARD: Well, there’s a couple of hidden valves that you – if you have a dishwasher or a washing machine, those valves only open electrically. So, when you have your compressor on, make sure you run the dishwasher or run the washing machine to get the air out. Don’t forget the hoses on the washing machine, as well.
And what I like to do on the dishwasher itself is to actually disconnect that supply to the dishwasher solenoid valve down low in front of the dishwasher. Because if a little water gets in there and splits that solenoid, it’s a very expensive repair.
TOM: Yeah, we don’t want any surprises when we’re ready to start our vacation.
RICHARD: That’s right.
TOM: Good advice. Richard Trethewey, the plumbing and heating contractor from TV’s This Old House, thanks for stopping by The Money Pit.
RICHARD: Great to be here.
LESLIE: Alright. You can catch the current season of This Old House and Ask This Old House on PBS. For local listings and a step-by-step video on how you can drain pipes on your vacation home and other how-to videos, visit ThisOldHouse.com.
TOM: And This Old House is brought to you by State Farm. Like a good neighbor, State Farm is there.