Thanks, Mike. Regrettably neither of those devices are in the sytem. I almost wish there was a primary suspect - but this is a simple small residence - faucets, tub, toilets, a shower, standard 30 gal water heater, a washing machine. Really has me stumped. Thanks again. Charlie SwartzI'm not a pro plumber, but my best guess is that you're getting air into your supply lines from a failing air bladder on a water heater expansion tank or a water pressure booster pump tank, if you have either of those.
If you do, it would be faster and simpler just to replace the bladder tank to solve your problem.