August 16, 2011

The Soft and Hard Side of Your Water

When it comes to CaCO3, otherwise known as limestone, some like it hard and some like it soft.  Water hardness is the amount of soap precipitating minerals in the water. The harder the water, the less effective soap will be.

Since 1948, lime softening has been a part of the treatment process at Des Moines Water Works.  Powdered lime is mixed with water, forming a slurry, or thick liquid.  This mixture is then fed into the four lime softening basins.  As the water passes through the softening process, the lime slurry attaches to excess minerals in the water forming a lime floc.  The limestone floc then settles to the bottom of the basins as by-product.

This process is beneficial for several reasons. First, removing the minerals helps lessen the hardness of the water, which allows detergents and soaps to clean better.  Lime softening also kills harmful germs and bacteria, and causes a thin protective coating to form on the inside of pipes. This coating inhibits leaching of lead from older pipes into the drinking water supply.

DMWW strives to maintain the total hardness of drinking water to less than 150 mg/L.  This equates to 8.76 grains of hardness on a water softener setting.  Individuals who prefer softer water may consider purchasing and installing a water softening unit in their home.  However, excessively soft water is very corrosive to your pipes.

There is no adverse health effect associated with hard or soft water – it’s just a matter of personal preference.  You can get daily water hardness readings from DMWW’s lab reports.

Posted by: Laura Sarcone 2 Comments
Labels: , , , , , , Posted in Water Quality, Water Treatment

2 Responses to “The Soft and Hard Side of Your Water”

  1. April 13, 2014 at 9:28 pm, Oscar Hurtado-Gonzales said:

    Hi There,
    Could you please provide a workable link to the DMWW’s lab reports (the link in this website is not working). I would be interested in checking out a few reports to confirm what you stated about the total hardness of drinking water to be less than 150 ppm.


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