After further review, KAR Labs test kits will not be resumed.
Here are some alternatives:
Well known and respected:
http://www.ntllabs.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=NTL&Category_Code=Homeowner
Watercheck 1 &2 has fairly comprehensive lab testing. $119.99
Well-Check adds Coliform and E-coli bacteria testing $159.99
Test kit needs overnight return shipping. Can optionally provide the shipping fee for
an unknown price, or you provide the overnight return shipping. It would be interesting to hear what they charge for shipping. It may be distance based.
Not frequently discussed, but there was a test report posted here recently:
http://envirotestkits.com/drinking-water-test-kits/#
I don't know the kit return shipping situation.
DIY test strip kits: prolabinc.com
http://prolabtestkits.com/product/total-water-quality-kit/ $24.95
http://prolabtestkits.com/product/water-quality-test-kit/ $9.95
DIY test strips are probably a lot less accurate.
For Illinois residents:
https://www.isws.illinois.edu/chem/psl/TestKit.asp
Less expensive but significantly slower than other labs from what I can tell.
I expect other states have useful offerings.
County testing usually is not sufficient for water treatment purposes. It often just checks for bacteria, lead, and maybe health things.
Very incomplete information follows, and I may have missed important stuff.
For water treatment purposes IMO, you should, at a minimum get numbers on hardness, pH, iron, manganese. In some areas, you should get numbers for arsenic , corrosivity.
Of interest are other things that are not things usually treated for, but could be treated for with RO: silica, sulfate, sodium, chloride