I will probably kick myself when this one is solved. Patio faucet (and all faucets) have always worked fine. Pressure strong. Today, patio faucet gives no water - none. Worked a couple days ago. Possible clues to mystery: 1. There is no isolation valve at another location. 2. Valve at patio faucet definitely works (opens and closes - no broken parts). 3. Every other faucet everywhere works fine. 4. House is pier & beam. No breaks in line. 5. Can't see how a sudden clog could occur in a supply line that is so bad it is capable of instantly reducing good pressure to absolutely no flow. 6. No screen/filter issues because there are none on the faucet. 7. About 10 days ago, pump to well went out. Will replace shortly, but FYI, we are presently hooked up to neighbor's well by chain of garden hoses. Again, though, every other faucet works fine. The mystery faucet also worked fine on several occasions while hooked up to neighbor. 8. There have been no changes of which we are aware between today and 2 or 3 days ago when faucet worked perfectly fine. 9. Kept valve closed for couple hours and then, enough pressure builds to supply a few milliliters. What a mystery!!! Is there such a condition that would cause negative (backward) pressure? Like I said, I'll probably kick myself for missing something obvious. Anyone have any ideas?

I installed an irrigation system with 6 zones around the house. I know it has to be blown out before winter sets in for obvious reasons. I understand that a portable compressor that puts out 50 psi and can maintain 150cfm will be enough to do the job if you run one zone at a time. Any other tips or things to watch out for while doing this job?