TOPIC: Replacing Exterior Irrigation Pipes

A friend of mine has a house up here in Washington that was built in the 20s', has had extensive modifications and fixes by the previous homeowner, many of which are noticeably half-assed. At some point the owner installed an exterior drip irrigation system connected to the house water supply, then as some point the pipes froze and cracked at the valves.

The piping for the irrigation is copper, connected to the cold water supply. The lines are coming from about 3' above the foundation, they never go through the crawlspace. The pipes exit the house, then has a valve and T's in three places to the underground lines to different areas in the yard. All the piping is 1" copper from the wall, through the valve, until the lines go underground. Once underground, the lines are then PVC to the different fixtures in the yard. Since the copper lines above ground have split due to freezing, we want to get those replaced before it freezes.

Here's the question: Would it be best to remove all the copper lines before they exit the siding and replace the lines and valves with PVC (as well as adding a blow-out port so they don't freeze again), or would it be better to move all the lines underground so none of them are exposed? We probably have about 2 weeks before the freeze, so I still have a window, but I'd rather not have to do this twice.

I am not an irrigation specialist.

I would contact one in your area and ask them. Maybe they also provide free consultation.

Now there may be seem HIP members that are specialized to answer your question.

My thoughts are, if you blow out the lines, it doesn't really matter whether the lines are copper or PVC; no water, no freezing.  Putting the lines underground will help if they are deep enough to be below the expected frost line.  Where I live that would be about 4'.  In an area where there would likely be a good snow cover, like a lawn, 2.5' would probably be enough, but under a drive way it may have to be as deep as 5'.  No idea how deep it would need to be where you are.  That doesn't seem like a reasonably solution because the lines have to get close to the surface anyways where ever the fixtures are.  Making a provision to be able to blow out the lines sounds like the best solution.
BTW, Poly pipe would be my choice of material over PVC. 

Thanks Bert!

That's kind of what I thought. We figured the best thing to do for the time being was to just replace the brass valves, as they are also cracked, insulated them, and removed the existing copper to the valves where they go underground. She's not going to need them till spring, so they just get blown out and capped. One of the few situations where procrastination is a good idea.

One solution might be to wrap the exposed pipe with electric pipe heat tape.  It plugs into 120V, and is wrapped around the pipe.  When the temperature drops the thermostats turns on the heat tape thus keeping the pipes from freezing.