First, you can clean the ...

First, you can clean the lines by running warm citric acid through the piping it will work on almost any type of material that has scaling.  Jumper in back as far as you can to pump this through your system if you are looking to clean up the scale/color.  Citric will probably work on your hard surfaces too, but something like hydrochloric (muriatic) acid will take up concrete and etch it.  Citric will not do that, but may take a little longer as it is a weak acid.

I cannot direct you on the laws for making potable water in your area, but you are almost certain to meet all criteria, if you install a small RO system.  There is not much to it, but if you are on a budget, then that may be a problem.  Unfortunately, sodium is difficult to remove in any other way.  The rest is going to be iron and other minerals fouling your RO membranes.  You might consult the manufacturer about cleaners to use periodically if your pressure gets too high due to fouling.

Good luck,

Sean L. Roop - Principal and Senior Consultant - Industrial and Engineering Consultants, LLC