Here’s instructions on making a home-made meter, which tests for Total Dissolved Solids (TDS), EC (electrical conductivity), PPM (parts per million).
If you want to go with a store-bought item, here’s a $65 item that works quite well. According to the article, the ideal drinking water range is 0-50. The EPA Secondary Regulations advise a maximum contamination level (MCL) of 500mg/liter (500 parts per million (ppm) for Total Dissolved Solids (TDS). That’s 10X higher than the “50″ in the recommended drinking water range of 0-50.
“A high level of TDS is an indicator of potential concerns, and warrants further investigation… most often, high levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water.” – EPA
