13 Jul. 18

Soft Water – It’s Not For Drinking

Metropolitan Government of Nashville and Davidson County prepared this
information. It also is available on their website at http://www.nashville.gov/water/soft_h2o.htm

Soft water
is neither healthy nor desirable for drinking! If you were a
steam iron or a washing machine it would be great, but we are neither! There
are good reasons you should not be drinking soft water!

Water is a universal solvent. Most materials, especially metals, are
partially soluble in water. If that water is heated or softened it becomes
much more aggressive at leaching metals from water lines. Lead in soldered
joints and copper in pipe are particularly vulnerable and these are two of the
heavy metals which shouldn’t be present in significant amounts in your
drinking water.

Calcium and
magnesium are two minerals which make water “hard.” Both of these minerals are
classed as “contaminants,” but that’s a poor choice in terminology, for
calcium is essential in our diet! A softener merely exchanges one group of
non-toxic elements for another group of non-toxic elements. Water hardness is
measured either in grains per gallon (GPG) or as calcium hardness in
milligrams per liter (mg/l) or parts per million (ppm). GPG is based on
calcium hardness. To convert from calcium hardness ppm, just divide by a
factor of 17.2 and this gives you hardness in GPG. A soft or slightly hard
water has up to 3.5 GPG; moderately hard water runs from 3.5 to 10.5 GPG; and
very hard water is greater than 10.5 GPG. If your water is over 7 GPG, you
might want to consider a softener just for the laundry.

Metro water is on the low side of moderately hard at 4.1 GPG (that is 70
mg/l of calcium hardness. This is an excellent value and highly desirable!
Cities which have soft water are having difficulty meeting the new lead
standards in tap water. Metro has had none of these difficulties in meeting
the new standards!

A soft water is
aggressive at leaching metals (like lead) from your lines and faucets. Most
faucets are solid brass (with a relatively high lead content) and are chrome
plated. This means that if you have soft water, there is a great chance that
your initial drawing of cold water will have a higher lead content than
normal. Hot or warm water from the tap should never be used for cooking,
shortcuts, drinking water, beverages, or infant formula as it could be higher
in heavy metals like lead!

making the water more corrosive and aggressive at leaching metals from your
lines and fixtures, the zeolite beads from water softening systems may
back-siphon into your toilet tanks, and the soft water may attack vital
plumbing parts. While supposedly solving one set of problems, the softener
could possibly introduce other problems which you may or may not be aware of!
A water softener, besides leaching lead and other metals from your plumbing,
can increase your sodium intake. In a water softening device hard water flows
through synthetic resin beads. Sodium ions (salt) are loosely attached to each bead
and the water exchanges hardness ions (calcium and magnesium) for the soft
sodium ions. These devices can also be costly to run since they can waste up
to 120 gallons for every 1,000 delivered.

A water softener is not designed (nor is it effective) to remove lead and
other metals, chlorine, taste/odor compounds, nor chlorine by-products. Its
purpose is only to make a hard water soft. Water treated to remove chlorine
may encourage the formation of black rings in toilet bowls!

Soft water
is great for laundry, bathing, steam irons, and auto batteries, but definitely
not for anything else. If you are contemplating installing a softener, there
are serious questions you should ask: who will test the effectiveness of the
softener, how often will these tests be run, and how will my drinking water
quality be affected?

Metro Water Services does not test any home water treatment device,
including softeners, and does not recommend the use of particular devices!