How clean is your drinking water? We first test our tap water, then our RO (Reverse Osmosis) filtered water and finally the RO water filtered through another standard "Brita" filter.
The instrument used is fairly inexpensive and very simple to operate.
It will measure TDS (Total Dissolved Solids), Electrical Conductivity (which will show how much metal is in your water) and Temperature in degrees C and F.
You can get one from 2Ground.com at this link:
or in this "Collection" should the direct product link change: