2008 Water Quality Table for Dominguez

Primary Drinking Water Standards

Groundwater

Purchased
Surface Water

Distribution
System-Wide

Radiological

Year Tested

Unit

MCL

PHG (MCLG)

Exceeded Standard?

Range

Average

Range

Average

Range

Average

Source of Substance

Gross alpha particle activity

2005–2008

pCi/L

(0)

ND–11

ND–7.6

4.3

n/a

Erosion of natural deposits

Radium 228

2005–2008

pCi/L

0.019 (0)

ND–2.3

0.27

n/a

Erosion of natural deposits

Uranium

2005–2008

pCi/L

0.43

n/a

1.6–3.4

2.4

n/a

Erosion of natural deposits

Inorganic Chemicals

Year Tested

Unit

MCL (SMCL)

PHG (MCLG)

Exceeded Standard?

Range

Average

Range

Average

Range

Average

Source of Substance

Aluminum

2006–2008

ppm

1 (0.2)

0.6

n/a

0.06–0.25

0.12

n/a

Erosion of natural deposits; residue from some surface water treatment processes

Arsenic

2006–2008

ppb

0.00

ND–2.7

0.3

ND–2.8

2.4

n/a

Erosion of natural deposits; runoff from orchards; glass and electronics production wastes

Barium

2006–2008

ppm

ND–0.17

0.02

ND–0.13

0.06

n/a

Discharges of oil-drilling waste and from metal refineries; erosion of natural deposits

Fluoride (naturally occurring)

2006–2008

ppm

0.16–0.43

0.3

n/a

0.2–1.0

0.6

Erosion of natural deposits; water additive that promotes strong teeth; discharge from fertilizer and aluminum factories

Fluoride (treatment)1

2008

ppm

n/a

0.2–1.0

n/a

Water additive for dental health

Nitrate (as nitrogen)

2008

ppm

n/a

ND–0.9

0.6

n/a

Runoff and leaching from fertilizer use; leaching from septic tanks and sewage; erosion of natural deposits

Selenium

2006–2008

ppb

(50)

ND–9.5

1.8

n/a

Discharge from petroleum, glass, and metal refineries; erosion of natural deposits; discharge from mines and chemical manufacturers; runoff from livestock lots (feed additive)

Year Tested

Unit

MCL

PHG (MCLG)

Exceeded Standard?

Highest Level

Lowest Monthly Percent

Highest Level

Lowest Monthly Percent

Highest Level

Lowest Monthly Percent

Source of Substance

Turbidity (surface water requiring filtration)2

2008

NTU

n/a

0.06

100%

n/a

Soil runoff

Distribution System Monitoring

Year Tested

Unit

MCL

PHG (MCLG)

Exceeded Standard?

Range

Highest Running Annual Average

Range

Highest Running Annual Average

Range

Highest Running Annual Average

Source of Substance

Bromate3

2008

ppb

(0)

n/a

4.4–10

7.8

n/a

Byproduct of drinking water disinfection

Total haloacetic acids

2008

ppb

n/a

7.0–38.8

21.4

Drinking water disinfectant added for treatment

Total trihalomethanes

2008

ppb

n/a

26.9–114.5

50.5

Drinking water disinfectant added for treatment

Total chlorine residual

2008

ppm

n/a

0.02–2.69

1.89

Drinking water disinfectant added for treatment

Total organic carbon4

2008

ppm

n/a

0.24–1.7

1.0

2.0–3.1

2.7

n/a

Various natural and manmade sources

Microbiological

Year Tested

Unit

MCL

(MCLG)

Exceeded Standard?

Highest Monthly

Source of Substance

Total coliform (systems
with >40 samples/month)

2008

positive samples

(0)

n/a

1.89%

Internal corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives

Other Regulated Substances

Metals

Year Tested

Unit

PHG

Exceeded Standard?

90th Percentile

No. of Sites Exceeding AL

90th Percentile

No. of Sites Exceeding AL

90th Percentile

No. of Sites Exceeding AL

Source of Substance

Copper

2006

ppm

1.3

0.3

n/a

0.17

0 of 50

Internal corrosion of household plumbing systems; erosion of natural deposits; leaching from wood preservatives

Lead

2006

ppb

n/a

2.5

0 of 50

Internal corrosion of household plumbing systems; discharge from industrial manufacturers; erosion of natural deposits

Secondary Drinking Water Standards and Unregulated Compounds

Inorganic Chemicals

Year Tested

Unit

SMCL

PHG (MCLG)

Exceeded Standard?

Range

Average

Range

Average

Range

Average

Source of Substance

Boron

2006–2008

ppm

NL=1

n/a

0.79

130–200

165

n/a

Erosion of natural deposits; seawater influence

Calcium

2006–2008

ppm

n/a

16–370

23–74

n/a

Erosion of natural deposits

Chloride

2006–2008

ppm

500

n/a

19–230

111

72–104

n/a

Erosion of natural deposits; seawater influence

Color5

2007–2008

Units

n/a

Yes

ND–40

1–3

n/a

Naturally occurring organic matter

Hardness

2006–2008

ppm

n/a

52–1400

250

108–308

187

n/a

Erosion of natural deposits

Iron

2006–2008

ppb

300

n/a

ND–180

n/a

Leaching from natural deposits; industrial wastes

Magnesium

2006–2008

ppm

n/a

1.6–110

11–29

n/a

Erosion of natural deposits

Manganese

2006–2008

ppb

n/a

ND–70

n/a

Leaching from natural deposits

Odor

2006–2008

Units

n/a

ND–1

0.08

2–3

n/a

Naturally occurring organic matter

2006–2008

Units

n/a

6.8–8.7

7.8

8.0–8.4

8.2

n/a

Inherent characteristic of water

Sodium

2006–2008

ppm

n/a

50–350

106

56–109

n/a

Erosion of natural deposits; seawater influence

Specific conductance

2006–2008

µS/cm

1600

n/a

350–780

504

516–1090

747

n/a

Erosion of natural deposits; seawater influence

Sulfate

2006–2008

ppm

500

n/a

ND–310

47–275

134

n/a

Runoff/leaching from natural deposits; industrial wastes

Total dissolved solids

2006–2008

ppm

1000

n/a

210–540

360

283–678

436

n/a

Runoff/leaching from natural deposits

Vanadium

2006–2008

ppb

NL=50

n/a

3.1–5.1

4.3

n/a

Erosion of natural deposits; manufacturing of alloys and steel

Disinfection Byproducts

Year Tested

Unit

MCL

PHG

Exceeded Standard?

Range

Highest Annual Average

Range

Highest Annual Average

Range

Highest Annual Average

Source of Substance

n-Nitrosodimethylamine

2008

ppt

NL=10

n/a

2.4–7.4

n/a

Byproduct of drinking water chlorination; industrial processes

1Cal Water does not add fluoride to its groundwater supply. However, low levels of fluoride occur naturally. In November 2007, Metropolitan Water District of Southern California (MWD) began fluoridating its treated surface water, which Cal Water purchases. The range of fluoride concentrations indicated under "Purchased Surface Water" is the results of samples collected from the effluent of MWD treatment plants after fluoride was added. Since the system receives a blend of groundwater with naturally occurring fluoride and fluoridated surface water, fluoride levels are checked throughout the distribution system every month. The range and average fluoride concentrations indicated under "Distribution System-Wide" are the results of these samples. The optimal fluoride level for the Dominguez system is 0.8 ppm, with a control range of 0.7–1.3 ppm.

2For surface water systems, the Treatment Technique (TT) dictates that the turbidity level of the filtered water shall be less than or equal to 0.3 NTU in 95% of the measurements taken each month and shall not exceed 1 NTU at any time. Turbidity is a measure of the cloudiness of the water and is an indicator of treatment performance. Turbidity is monitored because it is a good indicator of the effectiveness of the filtration system.

3Some people who drink water containing bromate in excess of the MCL over many years may have an increased risk of getting cancer.

4Total organic carbon (TOC) has no health effects; however, TOC provides a medium for the formation of disinfection byproducts. These byproducts include THMs and HAAs. Drinking water containing these byproducts in excess of the MCL may lead to adverse health effects, liver or kidney problems, or nervous system effects, and may lead to an increased risk of cancer. Concerns regarding disinfection byproducts are based upon exposure over many years. The groundwater data is an average of data collected, and is not the highest running annual average.

5Color is present in one of five groundwater wells at levels that exceed the SMCL of 15 ppb. SMCLs are set to protect you against unpleasant aesthetic effects, such as color, taste, odor, and the staining of plumbing fixtures and clothing. Exceeding these MCLs does not pose a health risk. We are currently evaluating treatment to remove color from this well.

How to Read This Table

We test your water for more than 100 regulated contaminants. The table in this report lists only those that were detected.

The table shows water quality test results divided into two main sections: “primary standards” and “secondary standards.” Primary standards protect public health by limiting the levels of contaminants in drinking water. Secondary standards are limits for substances that could affect the water's taste, odor, or appearance.

Definitions

µS/cm = measure of specific conductance
n/a = not applicable
ND = not detected
NTU = nephelometric turbidity unit
pCi/L = picoCuries per liter (measure of radioactivity)
ppb = parts per billion (micrograms per liter)
ppm = parts per million (milligrams per liter)
SMCL = secondary maximum contaminant level

Public Health Goal (PHG): The level of a contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by the California Environmental Protection Agency.

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 are set by the U.S. Environmental Protection Agency (USEPA).

Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the PHGs (or MCLGs) as are economically and technologically feasible. Secondary MCLs are set to protect the odor, taste, and appearance of drinking water.

Maximum Residual Disinfectant Level Goal (MRDLG): The level of a disinfectant added for water treatment below which there is no known or expected risk to health. MRDLGs are set by the USEPA.

Maximum Residual Disinfectant Level (MRDL): The level of a disinfectant added for water treatment that may not be exceeded at the consumer's tap.

Notification Level (NL): A health-based advisory level for an unregulated contaminant in drinking water. It is used by the California Department of Public Health to provide guidance to drinking water systems.

Primary Drinking Water Standard (PDWS): MCLs and MRDLs for contaminants that affect health, along with their monitoring, reporting, and water treatment requirements.

Regulatory Action Level (AL): The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow.

Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

Potential Sources of Contamination

All drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the U.S. Environmental Protection Agency (USEPA) Safe Drinking Water Hotline at (800) 426-4791.

The sources of drinking water (both tap and bottled) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or human activity. Contaminants that may be present in source water include:

Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.

Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming.

Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses.

Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, and septic systems.

Radioactive contaminants, which can be naturally occurring or the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (USEPA) and the California Department of Public Health (Department) prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. Department regulations also establish limits for contaminants in bottled water, which must provide the same protection for public health.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immunocompromised people, such as those with cancer undergoing chemotherapy, those who have undergone organ transplants, those with HIV/AIDS or other immune system disorders, some elderly people, and infants, can be particularly at risk from infections. These people should seek advice from their health care providers about drinking water. USEPA/Centers for Disease Control and Prevention (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline at (800) 426-4791.

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