Wow, thanks John! I plan at this point to do most of the work myself. Luckily the flow seems really good out of all of the faucets (like "stand back!") and static pressure is right at 70 psi. Tested the water last night and it looks quite good, fairly soft, slightly basic, fairly high alkalinity, no iron, copper,nitrates or chlorine. It appears that the problems we are having are related almost entirely to rust bacteria.
I didn't know about using 6" brass pipe as a sub for the dielectric union, that's a great help. I really didn't want to hassle with replacing galvanized pipe with galvanized pipe, but I'm concerned that some of our our old wiring might be grounded to the plumbing and I'd like to play it safe in terms of electrical bonding. We have neat old textured plaster over lath walls in the house and really don't want to tear them up to replace all of the pipes. But I can certainly redo all the exposed piping from the cold water inlet to the heater and out of the heater with copper. My neighbor who owns the water company we are supplied by reconnected us from our crappy well to his water supply 30 years ago. Left the pressure tank in the system ( I suspect that and the old heater are a veritable metropolis of rust bacteria), failed to bond the galvanized inlet pipes on either side of a plastic union, left unsupported runs of over 10 feet long, water filter hanging sideways, etc, etc. Now that I have studied the code I can say that I wish he had too!
As an aside I just installed one of those dual flush thingies in one of our toilets. Interesting gadget, one button flushes only part way for #1 and there is a second button for launching #2 with added vigor. The #1 setting is a little hit and miss, but it does seem like it should save water. Also took the straightforward approach to conservation and put a 1 gal jug of water in the tank.
