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Water Quality Charts
Understanding the Charts
The following list explains the terms used in the charts:
Action Level (AL): The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.
Maximum Contaminant Level Goal
(MCLG): The level of a contaminant in drinking
water below which there is no known or expected risk to
health. MCLGs allow for margin of safety.
Maximum Contaminant Level (MCL): The highest permissible level of a contaminant in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology.
Maximum Residual Disinfectant Level (MRDL): The highest level of disinfectant allowed in drinking water. There is convincing evidence that the addition of a disinfectant is necessary for control of microbial contaminants.
Maximum Residual Disinfectant Level Goal (MRDLG): The level of drinking water disinfectant below which there is no known or expected
risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contamination.
Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.
MFL: million fibers per liter (a measure of asbestos)
N/A: Not applicable
ND: Not detected
Not Regulated: The contaminant
is not currently regulated by the Environmental Protection
Agency.
NTU: Nephelometric Turbidity Units
pCi/l: Picocuries
per liter. A
measure of radioactivity
in water.
Points-of-entry: Entry
point to the distribution system which
is representative of each well after
disinfection.
ppb: Parts per billion.
One part per billion is equal to one
teaspoon in 1,302,000 gallons - enough to fill a typical bathtub
more than 40,000
times.
ppm: Parts per million.
One part per million equals one teaspoon
in 1,302 gallons, which is enough water
to fill a typical bathtub more than
40 times.
Remember
that these substances are shown in
parts per million or parts per billion.
As you will see in these charts,
water delivered by SAWS is of excellent
quality.
|
Inorganic Contaminants (2002-2007) |
|
Substance |
Concentration Range found in Water |
Average Concentration Found in Water |
MCL |
MCLG |
Possible Source |
|
Nitrate (ppm) |
0 – 2.41 |
1.66 |
10 |
10 |
Erosion of natural deposits; Runoff from fertilizer
use; Leaching from septic tanks, sewage. |
|
Barium (ppm) |
0.024 – 0.112 |
0.05 |
2 |
2 |
Erosion of natural deposits; Discharge of drilling wastes; Discharge from metal refineries. |
|
Fluoride (ppm) |
0.19 – 2.02 |
0.7 |
4 |
4 |
Erosion of natural deposits; Discharge from
fertilizer and aluminum factories.
Added for dental health. |
|
Combined Radium 226 & 228 (pCi/L) |
0 – 0.7 |
0.02 |
5 |
0 |
Erosion of natural deposits |
| Gross
alpha
adjusted
(pCi/l) |
0 – 2.7 |
0.46 |
15 |
0 |
Erosion
of natural
deposits |
|
Chromium (ppb) |
0 – 8.4 |
2.4 |
100 |
100 |
Discharge from steel and pulp mills; erosion of natural deposits |
| Gross beta emitters (pCi/L) |
0 – 2.6 |
0.23 |
50 |
0 |
Decay of natural and manmade deposits. |
| Selenium (ppb) |
0 – 5.1 |
0.2 |
50 |
50 |
Discharge from petroleum and metal refineries; erosion of natural deposits; discharge from mines. |
|
|
Organic Contaminant
|
|
Testing waived, not reported or none detected. |
|
Maximum Residual Disinfectant Level |
|
Disinfectant |
Test
Year |
Concentration Range found in Water |
Average Concentration Found in Water |
MCL |
MCLG |
Possible Source |
|
Chlorine Residual, Free (ppm) |
2007 |
0.35 – 1.57 |
0.85 |
4 |
4 |
Disinfectant used to control microbes. |
|
|
Secondary Constituents (2003-2007) |
|
Constituent |
Concentration Range |
Avg. Concentration |
Limit (ppm) |
|
Aluminum (ppb) |
0 – 0.077 |
0.003 |
50 |
|
Bicarbonate (ppm) |
176 - 278 |
218 |
NA |
|
Calcium
(ppm) |
42.5 – 101 |
76.9 |
NA |
|
Chloride
(ppm) |
11 - 23 |
16 |
300 |
|
Copper
(ppm) |
0.001 - 0.037 |
0.01 |
1 |
|
Iron
(ppb) |
0 – 0.139 |
0.009 |
0.3 |
|
Magnesium
(ppm) |
12.1 – 26.7 |
16.5 |
NA |
|
Manganese (ppm) |
0 – 0.0037 |
0.0003 |
0.05 |
|
Nickel (ppb) |
0.002 – 0.003 |
0.002 |
NA |
| pH |
7.3 – 8 |
7.7 |
8.5 units |
|
Sodium
(ppm) |
8 - 20 |
11 |
NA |
|
Sulfate
(ppm) |
14 – 56 |
25 |
300 |
|
Total Alkalinity as Calcium Carbonate |
176 – 278 |
218 |
NA |
|
Total Dissolved Solids |
230 – 343 |
298 |
1,000 |
|
Total Hardness as Calcium Carbonate |
183 – 275 |
233 |
NA |
|
Total Hardness as Calcium/Milligram |
199 - 310 |
260 |
NA |
| Zinc |
0 – 0.141 |
0.02 |
5 |
|
|
What is Turbidity? |
|
Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease-causing organisms. These organisms include bacteria, viruses, and parasites that can cause symptoms such as nausea, cramps, and diarrhea and associated headaches.
|
|
Turbidity (2007) |
|
Substance |
Highest Single Measurement |
Lowest Monthly % of Samples Meeting Limits |
Limits |
Source of Contaminant |
|
Turbidity (NTU) |
0.20 |
100 |
0.3 |
Soil runoff |
|
|
What are Coliforms? |
|
Total coliform bacteria are used as indicators of microbial contamination of drinking water because testing for them is easy. While not disease-causing organisms themselves, they are often found in association with other microbes that are capable of causing disease. Coliform bacteria are more hardy than many disease-causing organisms; therefore, their absence from water is a good indication that the water is microbiologically safe for human consumption.
Fecal coliform bacteria and, in particular, E. coli, are members of the coliform bacteria group originating in the intestinal tract of warm-blooded animals and are passed into the environment through feces. The presence of fecal coliform bacteria (E. coli) in drinking water may indicate recent contamination of the drinking water with fecal material. |
|
Microbiological Contaminants Monitoring (2007) |
|
Substance |
MCL |
Amount Found |
Source |
|
Total Coliform Bacteria (presence) |
a |
Highest monthly % of positive samples: 2% |
Naturally present in the environment |
|
Fecal Coliform and E. coli (presence) |
b |
1 |
Human and animal fecal waste |
a presence of coliform bacteria in 5% or more of the monthly samples
b A routine sample and a repeat sample are total coliform positive and one is also fecal coliform or E. coli positive |
|
Lead and Copper Results (2007) |
|
Substance |
90th Percentile |
Action Level |
Number of residences exceeding Action Level |
Possible Source |
|
Lead (ppb) |
7.5 |
15 |
0 |
Corrosion of household plumbing; Erosion of natural deposits. |
|
Copper (ppm) |
0.213 |
1.3 |
0 |
|
|
Distribution Sampling for By-Products of Drinking Water Chlorination (Disinfection) (2007) |
|
Substance |
Concentration Range |
Highest Concentration Found |
MCL |
MCLG |
|
Total Trihalomethanes (THMs) (ppb) |
0 - 110.5 |
43.1 |
80 |
By-product of drinking water disinfection |
|
Haloacetic Acids (HAAs) (ppb) |
0 - 24.7 |
9.5 |
60 |
By-product of drinking water disinfection |
|
|
Unregulated Contaminants (2002-2007) |
|
Substance |
Concentration Range |
Average Level |
Source of Contaminant |
|
Bromoform (ppb) |
0 - 2.7 |
.45 |
By-product of drinking water disinfection |
| Bromodichloromethane (ppb) |
0 - 22.23 |
0.79 |
By-product of drinking water disinfection |
| Chloroform (ppb) |
0 - 19.83 |
0.59 |
By-product of drinking water disinfection |
| Chloromethane (ppb) |
0 - 1.46 |
0.04 |
By-product of drinking water disinfection |
|
Dibromochloromethane (ppb) |
0 - 15.23 |
1 |
By-product of drinking water disinfection |
|
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