A water specification sheet tells you how pure the water is. Here is what each number means, and how to check the water you receive against it.
Conductivity
Pure water conducts electricity very poorly; dissolved salts make it conduct. Conductivity, usually shown in microsiemens per centimetre (µS/cm), is the quickest single measure of how much is dissolved in the water. Lower is purer.
Total dissolved solids (TDS)
TDS estimates the total amount of dissolved minerals, usually in milligrams per litre (mg/L) or parts per million. Handheld TDS meters calculate it from conductivity, so the two numbers move together.
pH
Very pure water absorbs carbon dioxide from the air as soon as it is exposed, which makes it slightly acidic. A pH a little below 7 on high-purity water is normal and is not a sign of contamination.
Standard or lab grade?
Our spec sheet lists both a standard and a lab-grade specification. Batteries, coolant mixing and washing suit standard grade. If your method or equipment sets a conductivity or TDS limit, compare it with the lab-grade figures, or call us with the limit and we will tell you which suits.
Checking a delivery
- Check seals and caps are intact and the label matches your order.
- Take a sample in a clean container and read it with a calibrated conductivity or TDS meter.
- Compare the reading with the spec sheet and call us if it looks wrong.
- Keep containers sealed: open water picks up carbon dioxide and dust.
See demineralised water prices and sizes, IBC and bulk supply or the spec sheet.