Voltage Coffee Supply recommends caution when using sodium and hydrogen based ion exchange water softeners. Suggested pressure and flow rate from water mains: 45 to 80 psi (3 or 5 bar) and 8 liter per minute.
| value | units | min | max |
| T.D.S | ppm | 90 | 150 |
| Total Hardness | ppm | 70 | 100 |
| Total Iron | ppm | 0.0 | 0.02 |
| Free Chlorine | ppm | 0.0 | 0.05 |
| Total Chlorine | ppm | 0.0 | 0.1 |
| pH | 6.5 | 8 | |
| Alkalinity | ppm | 40 | 80 |
| Chloride | ppm | 0.0 | 30 |