City of Manteca – 2010 Report to Consumers on Water Quality Date of Report:  May 2011

 

(El informe contiene información importante sobre su agua potable. Tradúzalo o hable con alguien que lo entienda bien.)

 

The Safe Drinking Water Act requires that utilities issue a water quality report to consumers in addition to other notices that may be required by law.  This report details where our water comes from, what it contains, and the risks our water testing and treatment are designed to prevent.  The City of Manteca is committed to providing you with a safe and reliable water supply.  Informed consumers are our best allies in maintaining safe drinking water. 

 

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (USEPA) and the 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 that must provide the same protection for public health.

 

Drinking water, including bottled water, may reasonably be expected to contain 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 USEPA’s Safe Drinking Water Hotline (1-800-426-4791) or on the Internet at www.epa.gov/safewater.

 

Sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves natural deposits of minerals and radioactive material and can pick up substances resulting from the presence of animals or from 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 storm 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, stormwater runoff and residential uses.

·         Organic chemical contaminants including synthetic and volatile organic chemicals that are byproducts of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, agricultural application and septic systems.

·         Radioactive contaminants, which can be naturally-occurring or resulting from oil and gas production and mining activities.

 

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. USEPA/Centers for Disease Control (CDC) guidelines on appropriate means to lessen the risk of infection by Cryptosporidium are available from the Safe Drinking Water Hotline (1-800-426-4791).

 

NATIONAL PRIMARY DRINKING WATER REGULATION COMPLIANCE

 

This report was prepared by City of Manteca Public Works Department staff following prescribed reporting guidelines. For more information, call George Montross at 209-456-8400.  En Español, 209-456-8400.

 

CURRENT WATER SOURCE

 

The City of Manteca’s water is supplied from two sources. The first is groundwater, pumped from 17 wells located through out the City, and the second is treated surface water, from Woodward Reservoir, which is purchased from South San Joaquin Irrigation District (SSJID). During the summer of 2005, the City began receiving up to 11,500 acre feet¹/year of treated surface water from (SSJID). The majority of the City’s customers receive a mixture of groundwater and surface water, this mixture changes through out the year. For more specific water source data, contact the Public Works Department at 209-456-8400.

 

FUTURE WATER SOURCE 

 

The City of Manteca will continue to supply both groundwater and surface water.  In the future, the amount of surface water the City receives may increase by 7,000 acre feet/year and the City will continue to install new groundwater wells.

 

SOURCE WATER ASSESSMENT

 

·   Groundwater:

Source water assessments (SWA) were completed in December, 2001 for all existing City wells. New wells have SWA completed prior to the well producing any water for consumption by customers. The wells are considered most vulnerable to confirmed leaking underground storage tanks, gas stations, chemical/petroleum processing/storage facilities, metal plating/finishing/fabricating facilities, automobile body/repair shops and sewer collection systems.  For inquires about the source water assessment call the City of Manteca, Public Works Department at (209) 456-8400 located at 1001 West Center Street, Manteca, CA or the Department of Public Health at (209) 948-7696.

·   Surface Water:

Source water assessments were completed in September, 2001.  The Woodward Reservoir/Stanislaus River source is considered most vulnerable to recreational activities at Woodward Reservoir, confined animal facilities (dairy), cattle grazing, and wastewater disposal.  For inquires about the source water assessment call the Department of Public Health at (209) 948-7696.

 

PUBLIC PARTICIPATION

 

The public can participate in decisions that affect their water by attending City Council meetings when water related topics are scheduled for action.  Council meetings are held in the Council Chambers, 1001 West Center Street, on the first and third Tuesday of every month at 7:00 p.m.

 

CONCERNING NITRATE IN OUR WATER

 

Nitrate in drinking water at levels above 45 ppm is a health risk for infants of less than six months of age. Such nitrate levels in drinking water can interfere with the capacity of the infant’s blood to carry oxygen, resulting in a serious illness; symptoms include shortness of breath and blueness of the skin. Nitrate levels above 45 ppm may also affect the ability of the blood to carry oxygen in other individuals, such as pregnant women and those with certain specific enzyme deficiencies.  If you are caring for an infant, or you are pregnant, you should ask for advice from your health care provider.

 

lead in water

 

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children.  Lead in drinking water is primarily from materials and components associated with service lines and home plumbing.  The City of Manteca is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components.  When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking.  If you are concerned about lead in your water, you may wish to have your water tested.  Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline or at http://www.epa.gov/safewater/lead.

 

CONTAMINANTS MONITORED

 

The tables list all of the drinking water contaminants that were detected during the most recent sampling for the constituent.  The presence of these contaminants in the water does not necessarily indicate that the water poses a health risk.  We routinely perform additional monitoring for contaminants that could pose health concerns.  The Department allows us to monitor some contaminants less than once per year because the concentrations do not change frequently. Some of our data, though representative, are more than a year old.

 

*SUMMARY INFORMATION REGARDING ARSENIC LEVELS EXCEEDING THE FEDERAL MCL

 

What should I do?         You do not need to use an alternative (e.g. , bottled) water supply.  However, if you have specific health concerns, consult your doctor.

What does this mean?   This is not an immediate risk.  If it had been, you would have been notified immediately. However, some people who drink water containing arsenic in excess of the MCL over many years may experience skin damage or circulatory system problems, and may have an increased risk of getting cancer.  

What happened?           The Environmental Protection Agency (USEPA) reduced the Arsenic MCL from 50 ppb down to 10 ppb.  On November 28, 2008, the Department adopted the revised arsenic MCL level.   

What was done?            The City of Manteca is currently installing filters to remove arsenic from wells with arsenic levels above the Federal MCL of 10 ppb. In the meantime, the City is maximizing water production from sources with low arsenic levels.

 

HOW TO READ THE FOLLOWING TABLES

 

The column marked “Range of Detected Levels” shows the lowest, average and highest test results in our wells during the most recent monitoring. The “Average Detected Level” is determined from all test results from the most recent monitoring. “Typical Source of Contaminant” indicates where a substance usually originates. Other columns refer to:

 

·         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 is economically and technologically feasible. Secondary MCLs are set to protect the odor, taste, and appearance of drinking water.

·         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.

·         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 Residual Disinfectant Level (MRDL): 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.

·         Maximum Residual Disinfectant Level Goal (MRDLG): 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.

·         Primary Drinking Water Standards: MCLs for contaminants that affect health along with their monitoring and reporting requirements and water treatment requirements.

·         Secondary Drinking Water Standards (SDWS): MCLs for contaminants that affect taste, order or appearance of the drinking water.  Contaminants with SDWS do not affect the health at their MCL levels.

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

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

 

Table 1 - Source Water Quality Monitoring
Detection of Contaminants with a Primary Drinking Water Standard Sampled in 2007-2010
Contaminant	Units	MCL	PHG or (MCLG)	Range of Detected Levels				Typical Source of Contaminant
				Groundwater		Surface Water
				Average	Range	Average	Range
Arsenic*	ppb	10	0.004	11	5-21	ND	NA	Erosion of natural deposits
Barium	ppm	1	2	0.13	0.08-0.25	ND	NA	Erosion of natural deposits.
Dibromo- chloropropane (DBCP)	ppt	200	1.7	7	ND-106	ND (2005)	NA	Banned nematocide that may still be present in soils due to runoff/leaching from former use on vineyard and fruit trees.
Ethylene Dibromide (EDB)	ppt	50	10	2	ND-28	ND	NA	Banned nematocide that may still be present in soils due to runoff and leaching from grain and fruit crops.
Fluoride	ppm	2	1	0.14	0.10-0.21	ND	NA	Erosion of natural deposits.
Gross Alpha Activity (1)	pCi/L	15	(0)	6	ND-13	ND (2006)	NA	Erosion of natural deposits.
Nitrate (2)	ppm	45	45	26	4.1-44.9	ND	NA	Runoff and leaching from fertilizer use; erosion of natural deposits.
Total chromium	ppb	50	(100)	1.4	ND-6.5	ND	NA	Discharges from steel and pulp mills and chrome plating; erosion of natural deposits
Uranium	pCi/L	20	0.43	5.4	3.1-8.0	ND	NA	Erosion of natural deposits.
Detection of Contaminants with a Secondary Drinking Water Standard  Sampled in 2009-2010
Chloride	ppm	500	None	20	8-73	9.1	NA	Runoff/leaching from natural deposits
Sulfate	ppm	500	None	20	11-40	2.0	NA	Runoff/leaching from natural deposits.

 

Sampling Results for Sodium and Hardness Sampled in 2008-2010
Sodium	ppm	None	None	31	12-47	4	NA	Naturally occurring in ground and surface waters.
Hardness	ppm	None	None	166	79-250	46	NA	Naturally occurring in ground and surface waters.

 

Detection of Unregulated Contaminants Sampled in 2009 and 2010
Vanadium	ppb	Notification Level   50	38	29-50	ND	NA	Health Effects Language The babies of some pregnant women who drink water containing vanadium in excess of the notification level may have an increased risk of developmental effects, based on studies in laboratory animals.

 

UNITS USED IN REPORTING

·         ppm = parts per million  ·  ppt = parts per trillion · ND = None Detected ·  NS = Not Sampled ·  NA = Not Applicable

·     ppb = parts per billion     ·  pCi/L stands for picocuries per liter and is a radioactivity measurement

·         *  MCL violation of the Federal Arsenic Rule, See Page 2 for more details     

Notes from Table 1:

 

(1)        When a well exceeds a certain level of detected Gross Alpha Activity, the well water is tested for Uranium.  If the detected level of a water source is below the Gross Alpha and Uranium MCL, then the water source is considered safe and is left in service. 

 

(2)       More than half of the City wells have levels of Nitrates below 23 ppm and only require monitoring once every year.  Those wells with detected levels of Nitrate between 23 and 45 ppm are monitored quarterly to maintain an accurate picture of the Nitrate levels.  Any well that monitors a level of Nitrate above 45 ppm would be immediately retested and removed from service if the average of the two tests was above 45 ppm.  Further testing and evaluations would then be performed.

 

Table 2 – Distribution System Water Quality Monitoring

Sampling Results Showing the Detection of Coliform Bacteria

Microbial Contaminants

Highest percentage of positive samples in a month

Number of months in violation

MCL

MCLG

Typical Source of Microbe

Total Coliform Bacteria

1.3%

0

5% of total monthly samples

0

Naturally present in the environment

Sampling Results Showing the Detection of Disinfectant Residual and Disinfection By-Products

Contaminant

Date of Last Test Result

Units

MCL [MRDL]

PHG (MCLG) [MRDL]

Range of Detected Levels

Typical Source of Contaminant

Minimum

**Average

Maximum

Chlorine

December 2010

ppm

[4.0]

[4.0]

0.79

0.88

1.04

Drinking water disinfectant added for treatment

TTHMs (Total Trihalomethane)

October 2010

ppb

80

None

0

33

63

By-product of drinking water chlorination.

Halocetic Acids

October 2010

ppb

60

None

0

23

41

By-product of drinking water chlorination.

** The average is the highest running annual average reported in four quarters (every 3 months) of monitoring.   Sampling Results Showing the Detection of Lead and Copper

Contaminant

Date of Last Test Result

Units

Action Level

MCLG

90th Percentile Level Detected

Number of Sites Exceeding Action Level

Number of Samples Collected

Typical Source of Contaminant

Lead

July 2009

ppb

15

2

1.4

0

36

Internal corrosion of household water plumbing systems; erosion of natural deposits.

Copper

July 2009

ppm

1.3

0.17

0.11

0

36

Internal corrosion of household water plumbing systems; erosion of natural deposits.

 

Table 3 – Sampling Results Showing Treatment Of Surface Water Sources
Treatment Technique (3) (Type of approved filtration technology used)	Ultrafiltration Membrane
Turbidity Performance Standards (4) (that must be met through the water treatment process)	Turbidity of the filtered water must: 1  - Be less than or equal to 0.1 NTU in 95% of measurements in a month. 2 - Not to exceed 1.0 NTU any time.
Lowest monthly percentage of samples that met Turbidity Performance Standard No. 1.	98.4%
Highest single turbidity measurement during the year	0.087 NTU
Number of violations of any surface water treatment requirements	Zero

 

UNITS USED IN REPORTING

·         ppm = parts per million  ·  ppt = parts per trillion   · ND = None Detected  · NS = Not Sampled  · NA = Not Applicable 

·         ppb = parts per billion     ·  pCi/L stands for picocuries per liter and is a radioactivity measurement

·         NTU = Nephelometric Turbidity Unit

 

Notes from Table 3:

 

(3)           A required process intended to reduce the level of a contaminant in drinking water.

 

(4)           Turbidity (measured in NTU) is a measurement of the cloudiness of water and is a good indicator of water quality and filtration performance.  Turbidity results which meet performance standards are considered to be in compliance with filtration requirements.