I don't visit this site much, but whole house filters,with silver in the charcoal and a prefilter, both 4x10 in cannisters, will take metals and the nasties and most chemicals out of the water. On line like the water store has many filters as do other sites down to .5 micron carbon block. Usually only one filter here in most places in the states except RV parks using wells with a lot of sediment.
A prefilter of .25 filter carbon block will get most things before it eve gets to the primary filter. May have to change pre filter more often than the primary.
filter. It's no joke about the water south of the border