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Under
most conditions ground water contains greater amounts of
dissolved minerals than do surface supplies. But as
water percolates through sand, rock, and clay
formations, it loses much of the suspended matter, color
and bacterial contamination it gathers at the surface.
Thus deep
wells are likely to provide water that is clear,
colorless, low in bacteria and high in minerals. There
are exceptions, however. These make generalizations
somewhat difficult.
Springs
also provide ground water. On the whole they contain
significant amounts of dissolved:
Major
considerations in the use of ground waters include
-
The
presence of hardness and other minerals in larger
amounts than in the surface waters of the same
locality as a rule.
-
Iron
and manganese in many well supplies.
-
Hydrogen
sulfide sometimes present.
-
The
costs of pumping well water usually greater than
that for pumping surface water.
-
The
mineral content of several wells may differ widely
even though located close to each other.
-
Some
uncertainties of supply.
-
Limited
possibility of bacterial contamination as compared
to surface waters.
-
Generally
more consistent in temperature, minerals, etc. than
surface waters.
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