Might be able to help.
Wis DnR holds all public water info in a database, a little hunting with give you your specs.
http://prodoasext.dnr.wi.gov/inter1/pws2$.startup
Put in Columbus , Municipal community
Find
Click on Columbus
From there scroll down to
Other (non-bacteriological) Samples (263 Rows)
Click that
Scroll to the most recently dated Inorganics file with a good number of results (your case 26) click on that,
There you go, all you need.
Note: it looks like you have two sources 200 & 4, so you might want to avg them if you only have one town storage tank. Or not
Hope that helps
james