hi shelly,
not being a plumber, but employing many over the years, I understand you predicament.
Maybe you husband could at least have a look at the cold water line into the house and possibly blow through the pipes (air pressure or plunger), or if necessary replace with new copper. The cost, on average , is normally $800 or so but if your hubby does it then all the cheaper.
It sounds like you would have to do it when the tenants move out anyway (for sale)
hope it helps
brenan