Dishwashers and water hardness

When installing a new dishwasher the instruction manual may recommend settings based on the hardness of the water used by the machine.

Canberra’s water is soft, with a typical hardness value of about 40 mg/L as CaCO3.

In Australia the standard way to measure water hardness is in milligrams per litre as calcium carbonate (CaCO3). Many dishwasher manuals use different scales for water hardness.

The table below outlines some of the more common measurements which may help you in setting up your dishwasher.

Scale

Typical value for
Canberra water

Units

Note: These values are based on water supplied in 2005-06.

Milligrams per litre

40

mg/L as CaCO3

Millimol per litre

0.4

mmol/L

Millival per litre

0.8

mval/L

German degrees

2.2

°dH

French degrees

4

°TH

Parts per million

40

ppm