I have to replace about 20 feet of 1-inch black poly pipe between the
house and the five-zone manifold. About six feet of the pipe passes
under a paver brick walkway, which I don't want to disturb. The pipe is
about 6-8" below the soil, in Central New Jersey.

The first sprinkler company I called said the walkway must be disturbed,
and it would be up to me to make arrangements to remove and restore the
pavers. If I tackled that job myself, then I could easily replace the
pipe as well.

The second company said he would simply pass a 3/4" section of pipe
through the existing 1" pipe under the walkway, then use adapters to
transition back to 1 inch. (I don't know if meant to make the entire run
3/4" or just the part passing under the walkway. He's looking over the
job tomorrow.)

I asked about the reduced flow available through the 3/4" pipe. He said
that as long as I don't have more than five sprinkler heads on a zone, I
would be okay. My heads are all pop-ups, mostly rotaries by Hunter, but
a few non-rotaries, and there are only five per zone, so it sounds okay.
One site says that typical head delivers 1/2 gal/minute, so with five
per zone, that's 2.5 gpm, well below what a 3/4" pipe can deliver (about
23 gpm).

Any comments on using 3/4" pipe, or other suggestions for not disturbing
the walkway? One website suggested blasting a hole using full-force
water through a garden hose. Other suggestions are he
http://forums2.gardenweb.com/forums/...341731539.html

Thanks,

Ray