Water Hardness

I need to know the water hardness in my area in order to determine if I must add salt to the dishwasher.

I contacted the local utilities and they told me that there was 122 mg/l. The user manual has the following definitions on water hardness.

Clarke Degrees - 0-14, 14-36, 36-71, 71 or

dH - 0-10, 18-44, 45-89,89 or

mmol/l - 0-1.7, 1,8-4,4. 4.5-8.9, 8.9

To my dismay, the local utilities staff did not know how to convert the mg/l to mmol/l or dH.

Can you tell me the answer and how to calculate it?

Thanks.

Barb

I need to know the water hardness in my area in order to determine if I must add salt to the dishwasher.

I contacted the local utilities and they told me that there was 122 mg/l. The user manual has the following definitions on water hardness.

Clarke Degrees - 0-14, 14-36, 36-71, 71 or got it? 36-71=45-89=4.5-8.9=121-180 ... all the same.

dH - 0-10, 18-44, 45-89,89 or

mmol/l - 0-1.7, 1,8-4,4. 4.5-8.9, 8.9

To my dismay, the local utilities staff did not know how to convert the mg/l to mmol/l or dH.

Can you tell me the answer and how to calculate it?

Thanks.

Barb

They all use 4 groups of numbers. Thus: Group 1 = Soft, 2nd group = moderately hard etc

Per http://water.usgs.gov/owq/Explanation.html , your water fits HARD @ 122mg/L (ie 3rd group of numbers, in any of the different ways of showing hardness) Got it? 36-71=45-89=4.5-8.9=121-180 ... all the same.


General guidelines for classification of waters are: 0 to 60 mg/L (milligrams per liter) as calcium carbonate is classified as soft; 61 to 120 mg/L as moderately hard; 121 to 180 mg/L as hard; and more than 180 mg/L as very hard.

This is another good read on water hardness and softening of it for washing, bathing etc.

http://ianrpubs.unl.edu/water/g1274.htm