How Do I Read This Water Quality Table?
It’s easy! Our water is tested to assure that it is safe and healthy. The column marked Detected Level shows the highest test results during the year. The column marked Major Sources in Drinking Water shows where substances usually originate. Footnotes explain important details. Abbreviations and definitions of key terms are shown in the table below:
Abbreviations and Definitions used in the Water Quality Table
AL |
Action Level: The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow. |
MCL |
Maximum Contaminant Level: The highest level of a contaminant that is allowed in drinking water. MCLs are set as close to the MCLGs as feasible using the best available treatment technology. |
MCLG |
Maximum Contaminant Level Goal: The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety. |
MRDL |
Maximum Residual Disinfectant Level: The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants. |
MRDLG |
Maximum Residual Disinfectant Level Goal: The level of a 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 contaminants. |
mrem |
Millirems: a measure of radiation absorbed by the body. |
N/A |
Not Applicable. |
ND |
Not Detectable: Not detectable at testing limits. |
NTU |
Nephelometric Turbidity Units: a measure of very small particulate matter in drinking water. |
pCi/l |
Picocuries per liter: a measure of radioactivity. |
ppb |
parts per billion, or micrograms per liter (µg/l). |
ppm |
parts per million, or milligrams per liter (mg/l). |
ppt |
parts per trillion, or nanograms per liter (nanograms/l) |
TT |
Treatment Technique: A required process intended to reduce the level of a contaminant in drinking water. |
2008 WATER QUALITY TABLE * |
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DETECTED CONTAMINANTS |
YEAR TESTED |
UNIT |
MCL / MRDL |
MCLG / MRDLG |
DETECTED LEVEL (FOR COMPLIANCE) |
DETECTEDRANGE |
MAJOR SOURCES IN DRINKING WATER |
VIOLA-TION |
Microorganisms |
MCL |
MCLG |
|
|
|
|
||
Total Coliform Bacteria (1) |
2008 |
% of Positive Samples |
5% |
0 |
2.4% |
N/A |
Naturally present in the environment. |
NO |
Total Organic Carbon (2) |
2008 |
Removal ratio |
TT |
N/A |
1.09 |
0.73 – 1.43 |
Naturally present in the environment. |
NO |
Turbidity (2) (8) |
2008 |
NTU |
TT = 1.0 |
N/A |
0.39 |
N/A |
Soil runoff. |
NO |
| TT = 95% of monthly samples < 0.3 | 99.35% < 0.3 |
|||||||
Radioactive Contaminants |
|
|
|
|
|
|
|
|
Combined Radium |
2008 |
pCi/L |
5 |
0 |
2.00 |
ND – 2.00 |
Erosion of Natural Deposits |
NO |
|
Disinfection Byproducts |
|
MCL |
MCLG |
|
|
|
|
|
Chlorite (2) |
2008 |
ppm |
1.0 |
0.8 |
0.530 |
0.230 – 0.550 |
By-product of drinking water chlorination. |
NO |
Haloacetic Acids (HAA5s) |
2008 |
ppb |
60 |
N/A |
18.8 |
9.5 – 29.3 |
By-product of drinking water chlorination. |
NO |
Total Trihalomethanes (TTHMs) (7) |
2008 |
ppb |
80 |
N/A |
85.7 |
35.4 – 170 |
By-product of drinking water chlorination. |
NO (7) |
Disinfectants |
|
MRDL |
MRDLG |
|
|
|
|
|
Chlorine |
2008 |
ppm |
4 |
4 |
0.49 |
0.03 – 1.80 |
Water additive used to control microbes. |
NO |
Chlorine Dioxide (2) |
2008 |
ppb |
800 |
800 |
750 |
50 – 750 |
Water additive used to control microbes. |
NO |
Inorganic Chemicals |
|
MCL |
MCLG |
|
|
|
|
|
Antimony (3) |
2008 |
ppb |
6 |
6 |
1 |
ND – 1 |
Fire retardants; ceramics; electronics; solder |
NO |
Arsenic (3) |
2008 |
ppb |
10 |
0 |
2 |
ND – 2 |
Erosion from natural deposits; runoff from orchards; Runoff from glass and electronics production wastes. |
NO |
Barium (3) |
2008 |
ppm |
2 |
2 |
0.009 |
0.005 – 0.009 |
Erosion of natural deposits; discharge of drilling wastes. |
NO |
Copper (4) |
2008 |
ppm |
AL = 1.3 |
1.3 |
0.046 |
N/A |
Corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives. |
NO |
Fluoride (2) (5) |
2008 |
ppm |
4 |
4 |
1.55 |
0.09 – 1.55 |
Water additive, which promotes strong teeth. |
NO |
Lead (6) |
2008 |
ppb |
AL = 15 |
0 |
<5 |
N/A |
Corrosion of household plumbing systems; erosion of natural deposits. |
NO |
Nitrate (3) |
2008 |
ppm |
10 |
10 |
0.50 |
ND – 0.50 |
Runoff from fertilizer use; leaching from septic tanks, sewerage; erosion of natural deposits. |
NO |
Synthetic Organic Chemicals including Pesticides and Herbicides |
|
MCL |
MCLG |
|
|
|
|
|
Di(2-ethylhexyl) phthalate (3) |
2008 |
ppb |
6 |
0 |
4.5 |
ND – 4.5 |
Discharge from rubber and chemical factories. PVC and other polymers including rubber. |
NO |
Unregulated Chemicals |
|
MCL |
MCLG |
|
|
|
|
|
Sodium (2) |
2008 |
ppm |
100 ** |
N/A |
17.6 |
13.2 – 17.6 |
Erosion of natural deposits; road-salt runoff; contained in water treatment chemicals. |
N/A |
* The data presented in this table is from the most recent testing done in accordance with regulations. Test results are from the Portsmouth Water and Fire District's distribution system unless otherwise noted by the footnotes.
** Although not regulated by the EPA, we are required by the Rhode Island Department of Health to test for sodium. There is no MCL for sodium, however the Health Advisory Level is 100 ppm.
Water Quality Table Footnotes
(1) In November, one (1) of forty-one (41) routine samples tested positive for Total Coliform Bacteria. Repeat samples taken within 24-hours tested negative for Total Coliform Bacteria. The drinking water was in compliance with EPA and Department of Health standards. All of the 500 other bacteria samples taken during the year tested negative for Total Coliform Bacteria.
(2) Measured after treatment at the Newport Water Department Lawton Valley Water Treatment Plant.
(3) Measured in the Newport Water Department raw water reservoirs prior to treatment.
(4) The detected copper level indicates the 90th percentile value of the 30 samples obtained at 30 high-risk homes in June. None of the 30 samples exceeded the Action Level for copper.
(5) Fluoride is added to the water at a rate of 1.0 ppm to help prevent tooth decay in children.
(6) The detected lead level indicates the 90th percentile value of the 30 samples obtained from 30 high-risk homes in June. None of the 30 samples exceeded the Action Level for lead. Infants and children who drink water containing lead in excess of the action level could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink this water over many years could develop kidney problems or high blood pressure.
(7) Some people who drink water containing TTHM’s in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous systems, and may have an increased risk of getting cancer. The detected level indicates the highest four-quarter, running annual average. Because the District is not routinely adding chlorine to the already chlorinated water it purchases from Newport Water, the RI Department of Health is not regulating TTHMs in the District’s system. Therefore, the District is not in violation of the standard even though its TTHM level exceeded the MCL. Please refer to Concerning TTHMs in Our Water elsewhere in this report.
(8) Turbidity is a measure of the cloudiness of the water. It is monitored because it is a good indicator of the effectiveness of the filtration system.