| These water
sources share several characteristics, although
they can be very different.
They utilise water from
local aquifers, similar to underground lakes.
Aquifers are formed where
water which has passed through the soil from
the surface reaches an impermeable layer and
collects.
These underground water
sources tend to be stable and the water can
take months or even years to reach them from
the surface.
 The
stratum, through which the water passes will
determine the final raw water characteristics
Although less susceptible
to seasonal variations these borehole sources
can have their own treatment issues. Water
from aquifers is often high in iron and manganese;
this is due to the lower pH often found in
these waters.
Both iron and manganese have
a distinctive taste noticeable at low concentrations
in water.
Limits for the levels of
both of these metals in private drinking water
are set at 200µg/l iron and 50µg/l
manganese.
Above these levels these
metals can cause discolouration to laundry
and can form deposits in water pipes, increasing
the risk of infection and contamination of
the final water source.
Although the two water
sources share several characteristics well
water sources tend to be more susceptible
to changes in the local environment and microbiological
contamination. The stability of a borehole
water source makes it preferable for use as
a private water supply.
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