I need to replace the pipes to outdoor faucets in my yard. I have
metal pipe running from meter to house. I have a T already in place in
this pipe. I want to:

1) Put a valve at the T so I can shut off all the water to the yard if
necessary.
2) Put a plastic cover over this - one of those green plastic
sprinkler valve covers, so I can have access to the valve whenever
necessary.
3) From the valve, use PVC schedule 40 to run to the faucets in the
back yard Maybe 100 feet total.
4) When I want a riser with a faucet, use maybe 2-3 feet of metal, and
have the riser tee off from the middle of this three foot run of
metal. That way you can kick and hit the riser, etc., and it won't
break. Then back to PVC until we get to the next riser.

Any problems with this? I've ran hundreds of feet of PVC sch 40 and
never once had a break - except for when I hit the risers. I'm
thinking PVC is OK for the straight runs, and then metal for the
risers so they don't break.

The line from meter to house is 100% metal. The PVC comes off of the
valve at the T, so if the PVC leaks or breaks, I can shut it off
immediately without effecting house water.