Also be sure that a ground is run from the ground bus (not neutral -- unless common) on your breaker panel to each side of your water (hot and cold). Do not do this yourself, but get an electrician to do it.
Also, you didn't mention if you have iron or other pipes. If it is all copper -- that's really weird. If you have iron and copper (and Al), then you have somehow created a galvanic cell (dissimilar metals in contact with each other). Avoid this -- use plastic fittings between metal, or replace the metal. You surely don't want aluminum pipes -- I've never heard of such a thing, but anything is possible.