Consumer Confidence
Water Quality Report
1999

Northern Distribution Area

Serving the Communities of

Boulder Creek, Brookdale, Ben Lomond and Zayante

[ 1998 Water Quality ] [ 1997 Water Quality ]

Sources of Water

The sources of drinking water (both tap 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 naturally-occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity.

Water Quality

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (USEPA) and State Department of Health Services(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 provide the same protection for public health. 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 USEPA’s Safe Drinking Water Hotline (1-800-426-4791).

Public Involvement

The Board of Directors of the San Lorenzo Valley Water District invites you to attend it’s meetings to express your views and opinions. The Board meets on the 1st and 3rd Thursday of each month. Meetings start at 7:00 p.m. at the District’s Operations building, 13057 Highway 9, Boulder Creek. Agenda information for the Board of Directors meetings can be obtained from the District’s website, www.slvwd.com.

Where Does Your Water Come From?

All water comes in the form of precipitation. Surface water accumulates mainly as a result of direct runoff from precipitation in the form of streams. Part of the precipitation that falls infiltrates the soil. Water drains downward (percolates) below the soil surface reaching a level at which all of the openings or voids in the earth's materials are filled with water. This zone of saturation is referred to as groundwater.Surface sources are used primarily from November to May. During these months, they may provide up to 100% of all District water. Streams utilized by the District are located on the western side of the valley on Ben Lomond Mountain and contain water from granite formations with very low mineral content. This results in very soft, pleasant tasting water. Collection points for these streams are in remote areas high within the District's protected watershed, away from human contamination.During the summer months from June-November the District blends surface water with groundwater sources (wells) located in the Quail Hollow area of Ben Lomond and the Olympia area of Zayante. All wells were constructed in accordance with State standards. These wells, with the exception of Olympia 2 and 3 in the Zayante area, produce very soft water with quality similar to our surface sources.Olympia Wells 2 and 3 have a higher mineral content, primarily iron, manganese and carbonate hardness. These minerals are harmless when consumed in water, but may affect the aesthetic qualities of the water such as taste, odor, and color. Dissolved gases present in groundwater may also affect taste.Consumers in the Hihn Road and Zayante areas, from time to time, may experience periods of discolored water caused by iron and manganese. As water comes in contact with chlorine at the well head and with oxygen during the trip through the mainline distribution piping, the iron and manganese precipitate deposits in the water mains. The District adds a polyphosphate chemical to slow down this process. However, this is not totally effective and some deposition still occurs. Occasionally, during higher flows, the deposits become dislodged resulting in discolored water. During this time, water is safe to use; however, you may want to avoid washing laundry as staining may occur. If you experience periods of discolored water, please contact the District at (831) 338-2153.

Possible Contaminants

Contaminants that may be in the water prior to treatment may include:Microbial Contaminants, such as viruses and bacteria, that may come from sewage treatment plants, septic systems, agricultural livestock operations and wildlife. Inorganic Contaminants, such as salts and metals, that 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, that may come from a variety of sources such as agricultural, urban stormwater runoff, and residential uses.Organic Chemical Contaminants, including synthetic and volatile organic chemicals, that are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, agricultural application, and septic systems.

Is The Water Safe For Everyone to Drink?

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 from their health care providers about drinking water. USEPA / Centers for Disease Control(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(1-800-426-4791).

State Standards and Monitoring

Individual water suppliers do not arbitrarily decide what constitutes "safe" drinking water. The U.S. Environmental Protection Agency and the California State Department of Health Services require all public water suppliers to meet stringent quality standards. Compliance is mandatory for public water utilities.In California, drinking water standards (also called Maximum Contaminant Levels, or MCLs) are established for two categories. Primary Standards are set for the protection of public health. Secondary Standards are set only for aesthetic qualities such as taste, odor and color, but do not represent any threat to health.

The District maintains a monitoring program to sample and test all water sources in accordance with State and Federal standards. Should the District fail to monitor, or the District’s water exceed the MCLs allowable in the Primary Standards, it is required by law to notify all customers of the nature of the problem and any possible health effects. Some contaminants that are routinely monitored by the District are bacteria, turbidity, inorganic chemicals, metals, general minerals, volatile organic chemicals (VOCs), disinfection by-products (THMs), and radiation.

The table below shows our test results for 1999. Once again, the San Lorenzo Valley Water District is pleased to report that our water quality met or surpassed all State and Federal criteria for public health protection. For additional information regarding water quality, or to obtain water quality information booklets, please contact the San Lorenzo Valley Water District at (831) 338-2153.

WATER QUALITY ANALYSIS FOR 1999

North System - Boulder Creek, Brookdale, Ben Lomond, Zayante

Primary Standards

GROUNDWATER

Range

Meas.

Average

DLR

PHG

MCL

Source

Aluminum

< .10

mg/L

< .10

.05 mg/L

n/a

1 mg/L

Erosion of natural deposits

Sulfate

5.5 - 180

mg/L

64

.5 mg/L

-

250 mg/L

Thallium

< 2

ug/L

<2

1 ug/L

0.1

2 ug/L

Leaching from ore-processing sites; discharge from electronics, glass and drug factories

Nitrite

< .5

mg/L

< .5

.4 mg/L

1

1 mg/L

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

Nitrate

< .1 - 24

mg/L

6.2

2 mg/L

45

45 mg/L

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

TCE (average of 6 samples)

N.D. - 6.6

ug/L

1.6

.5 ug/L

0.8

5 ug/L

Discharge from metal degreasing sites and other factories

Radioactive Contaminants

Gross Alpha

< 1 - 2.6

pci/L

< 1

1

0

15 pci/L

Erosion of natural deposits

Gross Beta

< 1 - 6.4

pci/L

2.1

4

0

50 pci/L

Erosion of natural and man-made deposits

Secondary Standards

Iron

< 50 - 160

ug/L

130

100 ug/L

-

300 ug/L

Leaching from natural deposits

Manganese

< 20 - 70

ug/L

25

20 ug/L

-

50 ug/L

Leaching from natural deposits

Additional Constituents Analyzed

Sodium

9.2 - 16

mg/L

12

---

-

---

Total Hardness

25 - 315

mg/L

119

---

-

---

Primary Standards

SURFACEWATER

Range

Meas.

Average

DLR

PHG

MCL

Source

Aluminum

< .1

mg/L

< .1

0.05

-

1 mg/L

Erosion of natural deposits

Sulfate

2.3 - 6.4

mg/L

3.5

0.5

-

---

Runoff/leaching from natural deposits

Thallium

< 2

ug/L

< 2

1

0.1

2 ug/L

Leaching from ore-processing sites; discharge from electronics, glass and drug factories

Nitrite

< .50

mg/L

< .50

0.4

1

1 mg/L

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

Radioactive Contaminants

Gross Alpha

< 1 - 1.4

pci/L

< 1

1

0

15 pci/L

Erosion of natural deposits

Gross Beta

< .8 - 3.4

pci/L

2.1

4

0

50 pci/L

Erosion of natural and man-made deposits

Additional Constituents Analyzed

Sodium

7.5 - 9

mg/L

8

---

-

---

Total Hardness

49 - 64

mg/L

56

---

-

---

Microbial Contaminants

Total Coliform

Highest % of positive samples Taken in any one month

2.3%

---

---

Naturally Present in the environment

Regulated at the Tap

Range

Meas.

MCL / AL

MCLG / PHG

Source

Lead(90th percentile)

3.9

ug/L

15 ug/L

2 ug/L

Corrosion of household plumbing, discharges from industrial manufacturers, erosion of natural deposits

Copper

530

ug/L

1300 ug/L

170 ug/L

Corrosion of household plumbing, erosion of natural deposits, leaching from wood preservatives

Surfacewater Treatment Technique * (Type of Approved Filtration Technology)

Microfloc upflow. Clarified with direct filtration

Turbidity **

Highest Single Measurement = .25 ntu

Soil Runoff

* A Required Process intended to reduce the level of a contaminant in drinking water

**Turbidity for the San Lorenzo Valley Water District shall not exceed 0.20 ntu for 95% of measurements taken each month

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

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.

Detection Limit for Reporting (DLR): A detected contaminant is any contaminant detected at or above its detection level for purposes of reporting.

n/a: not applicable, nd: not detectable at testing limit, ppb: parts per billion or micrograms per liter, ppm: parts per million or milligrams per liter, pCi/l: picocuries per liter (a measure of radiation).