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Drinking
Water Evaluation
What to Test on a Group B/Private
Drinking Water System
Now that you have an idea of the problems
that could occur, what should you test for? Substances found in
drinking water can be classified as:
- microbiological
- chemical
- physical
- radiological
Microbiological Tests detect "bugs," or microbes, that are too
small to be seen by the naked eye, such as bacteria or protozoans.
Many labs test for coliform bacteria, which originate from the same
source (feces) as many disease-causing microbes.
Chemical Tests are classified as inorganic or organic. Inorganic
chemicals are often associated with rocks, clay, sand, and other
earthy materials. Many organic chemicals are of plant or animal
origin.
Physical Tests examine characteristics of water including turbidity,
color, taste and odor, and temperature.
Radiological Tests study characteristics of water including the presence
of radium, uranium, and radon.
If
your water comes from a Group B public water system or if you have
a private well, you'll want to take the following approach on your
tests:
Initial
Tests:
A good set
of initial tests includes alkalinity, pH, and conductivity. If
your well draws from sandy materials or granite bedrock, test
once for corrosivity.
Annual
Tests:
If you live
in a rural area test annually for fecal or total coliform bacteria
and nitrate. If you suspect that septic systems, feedlots or fertilizer
applications have affected your groundwater, test more often.
The following table offers some guidelines.
| Problem |
Test
to Run |
| Feedlot |
Total
coliform, Giardia lamblia |
| Septic
system |
Total
coliform |
| Fertilizer
overuse |
Nitrate |
| Pesticide
spill or overuse |
Find
out which pesticide, and test for it. |
| Oil
spills |
Volatile
organics |
Other Problems:
Objectionable
taste and odor or discoloration of laundry and fixtures, suggests
you test for iron and manganese. If you suspect or know of pesticide
spills, oil spills, or leakage from waste storage areas, the expense
of special screening for metals, inorganic chemicals, volatile
organic chemicals, or herbicides/pesticides may be justified.
Use the following table as a guideline, and consult with your
local health department or county extension office to narrow down
the number of tests you need run.
| Problem |
Test
to Run |
| Odor and Taste |
Chloride, copper,
corrosivity, foaming agents, iron
manganese, odor, pH, sulfate, zinc |
| Staining |
Copper, corrosivity,
iron, manganese, |
| Discoloration
of water |
Aluminum, color |
| Hardness or deposits |
pH, total dissolved
solids (TDS) |
How
to Test
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