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.

 

 

  

WATER QUALITY TABLE *

CONTAMINANT

(footnote)

YEAR TESTED

UNIT

MCL / MRDL

MCLG / MRDLG

DETECTED

LEVEL

RANGE

MAJOR SOURCES IN DRINKING WATER

VIOLA-TION

Microorganisms

 

MCL

MCLG

 

 

 

 

Total organic carbon (1)

2004

Removal ratio

TT

N/A

1.47

0.73 – 1.47

Naturally present in environment.

NO

Turbidity (1) (7)

2004

NTU

TT = 1.0

N/A

0.64

N/A

Soil runoff.

NO

TT = 95% of monthly samples < 0.3

96.53% < 0.3

Disinfection Byproducts

 

MCL

MCLG

 

 

 

 

Chlorite (1)

2004

ppm

1.0

0.8

0.434

0.058 – 0.692

By-product of drinking water chlorination.

NO

Haloacetic acids (HAA5s)

2004

ppb

60

N/A

28.3

6.3 – 60.4

By-product of drinking water chlorination.

NO

Total Trihalomethanes (TTHMs) (6)

2004

ppb

80

N/A

67.7

38.1 – 103

By-product of drinking water chlorination.

NO

Disinfectants

 

MRDL

MRDLG

 

 

 

 

Chlorine

2004

ppm

4

4

0.52

0.03 – 1.86

Water additive used to control microbes.

NO

Chlorine dioxide (1)

2004

ppb

800

800

780

30 – 780

Water additive used to control microbes.

NO

Inorganic Chemicals

 

MCL

MCLG

 

 

 

 

Copper (3)

2004

ppm

AL = 1.3

1.3

0.04

N/A

Corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives.

NO

Fluoride (1) (4)

2004

ppm

4

4

1.32

0.08 – 1.32

Water additive, which promotes strong teeth.

NO

Lead (5)

2004

ppb

AL = 15

0

9

N/A

Corrosion of household plumbing systems; erosion of natural deposits.

NO

Nitrate (2)

2004

ppm

10

10

1.42

0.11 – 1.42

Runoff from fertilizer use; leaching from septic tanks, sewerage; erosion of natural deposits.

NO

Synthetic Organic Chemicals including Pesticides and Herbicides

 

MCL

MCLG

 

 

 

 

Simazine (2)

2004

ppb

4

4

0.12

ND – 0.12

Herbicide runoff.

NO

Radionuclides

 

MCL

MCLG

 

 

 

 

Beta/photon emitters (2)

2001

pCI/L

50 **

0

3.69

1.85 – 3.69

Decay of natural and man-made deposits.

NO

Combined radium (2)

2001

pCI/L

5

0

2.18

ND – 2.18

Erosion of natural deposits.

NO

Unregulated Chemicals

 

MCL

MCLG

 

 

 

 

Sodium (1)

2004

ppm

100 ***

N/A

20.2

16.5 – 20.2

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.

       ** The MCL for beta particles is 4 mrem/year. EPA considers 50 pCi/l to be the level of concern for beta particles.

     *** 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.                                                                                                                                          

NOTE: The state allows us to monitor for some contaminants less than once per year because the concentrations of these contaminants do not change frequently. Some of our data, though representative, are more than one year old.

 

 

 

Water Quality Table Footnotes

 

(1) Measured after treatment at the Newport Water Department Lawton Valley Water Treatment Plant.

(2) Measured in the Newport Water Department raw water reservoirs prior to treatment.

(3) 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.

(4) Fluoride is added to the water at a rate of 1.0 ppm to help prevent tooth decay in children.

(5) The detected lead level indicates the 90th percentile value of the 30 samples obtained from 30 high-risk homes in June. Two of the 30 samples exceeded the Action Level. 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 water this water over many years could develop kidney problems or high blood pressure.

(6) 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 average.

(7)  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.


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