Table of Contents
- At Risk: For People with special risks of infection
- OWASA Water Treatment System
- Get involved: How you can get involved in water quality and water supply issues
- For more information
- Drinking Water Quality: 2005 Test Results
- Contaminants
- Drinking Water Quality
- Additional Characteristics of our Drinking Water
- N.C. Source Water Assessment Program Results
- Where does our water come from?
For people with special risks of infection Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as people with cancer undergoing chemotherapy, people who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly people and infants can be particularly at risk of infections. These people should seek advice from their health care providers about drinking water. Guidelines from the U.S. Environmental Protection Agency (EPA) and Centers for Disease Control (CDC) on appropriate means to lessen the risk of infection by Cryptosporidium (please see additional information in this brochure about Cryptosporidium) and other microbial contaminants are available from the Safe Drinking Water Hotline (800-426-4791). To assist people with these infection risks, OWASA offers water treated with extra filtration, reverse osmosis and final disinfection with ultraviolet light. This water is available from an outdoor water vending machine on the west side of our Administration Building at 400 Jones Ferry Road , Carrboro. The cost is 40 cents per gallon. The water vending machine can fill a customer’s container of up to 5 gallons.
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Environmental Protection Agency's Safe Drinking Water Hotline: (800) 426-4791 |
(1) Raw water from University Lake and/or Cane Creek is pumped to the Jones Ferry Road Water Treatment Plant and (2) enters through the headworks facility, where non-toxic chemicals are added to make solid particles clump together and improve taste and odor. (3) Water is then pumped to either a “pulsator” or sedimentation basins, which allow time for solids to settle. (4) As water is pumped to filters, a liquid form of chlorine (bleach) is added for initial disinfection. (5) Water flows downward through dual media filters (sand and anthracite coal), where additional particles are removed. (6) The water enters the post-treatment stage, where we add fluoride for dental health and a chemical to set the pH (acidity/alkalinity) at the right level. The water then flows to the 1.5 million gallon clearwell (7) for temporary storage. Ammonia is added and it combines with chlorine to form “chloramines” to disinfect the water. (Please see the part of this report on “Additional Characteristics of our Water” for important information about chloramines and fish kept in aquariums.) Millions of gallons are pumped daily to one of several elevated storage tanks (8), which provide pressure so finished water can be delivered to your tap through a 345-plus mile network of water mains.
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How you can get involved in water quality |
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For More Information Para mas información
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You can get involved in water resource issues at the local, State and national levels in several ways. Becoming informed is the first step in being an effective participant. You can learn about water and water resource issues from news media; books in the library; Web sites such as those of the U.S. Environmental Protection Agency, American Water Works Association and other organizations; and by contacting OWASA (telephone: 968-4421; Web site: www.owasa.org; e-mail: webmaster@owasa.org). Expressing your views at public meetings, by contacting public officials, etc. is important when improvements, new policies and standards affecting water quality are needed or proposed. We invite you to attend and participate in meetings of the OWASA Board of |
Directors, which makes decisions on plans and policies and adopts the budget for our water and wastewater services. The OWASA Board meets at 7 pm on second Thursdays of most months in the Training Room at the OWASA Operations Center , 400 Jones Ferry Road , Carrboro; and on fourth Thursdays at the Chapel Hill Town Hall . On fourth Thursdays, OWASA Board meetings are televised live on the cable television systems in Chapel Hill and Carrboro.
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How to contact us: Orange Water and Sewer Authority |
Watershed protection: the first line of defense for our water supplies |
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Public Water Supply No.: 03-68-010 EPA's Drinking Water Hotline: |
To help protect the quality of our water supplies, the Orange County , Carrboro and Chatham County governments have adopted development standards and limits for University Lake and Cane Creek watershed areas in their planning jurisdictions. The standards are designed to reduce the amount of pollution carried in stormwater to the reservoirs by limiting the amount and types of construction and the amount of impervious surface (buildings, roads, etc.), and by controlling sediment, erosion and the disturbance of areas along streams. | In Orange County , standards for the University Lake and Cane Creek watersheds restrict density to one house per five acres, with some 2-acre lots allowed. For the part of the University Lake watershed in Chatham County , development is limited to one house per two acres. We commend the local governing boards for their actions to protect the public water sources through these standards. |
OWASA is the public, nonprofit, community-owned water and sewer agency serving the Carrboro-Chapel Hill community. |
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Drinking Water Quality: 2005 Test Results
In 2005, the Laboratory staff of four people at our Jones Ferry Road Water Treatment Plant tested our drinking water more than 47,000 times for over 100 substances in accord with State and Federal requirements. Listed below are the substances that were detected, all of which were below the regulatory limits. To get a list of all test results including substances not detected, please call our Water Treatment Plant Laboratory staff at 537-4227 or see our Website. There were no violations of the federal Safe Drinking Water Act or other related State and federal standards.
Substances Found in OWASA’s Drinking Water in 2005 |
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Substance and Unit Measurement |
MCL Violation? |
Highest Level Detected (except as noted) |
Range Detected |
Highest Level Allowed (MCL) |
Highest Level Goal (MCLG) |
Major Source in Drinking Water |
Microbiological Substances |
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Total Coliform Bacteria (percent) |
N |
1 |
0 to 1 |
presence of coliform bacteria in greater than 5% of the monthly samples |
0 |
Naturally present in the environment. |
Turbidity (NTU) |
N |
0.23 |
0.03 to 0.23 |
TT = 1 NTU |
0.3 |
A measure of the cloudiness of water. It may be caused by inorganic soil particles or fragments of organic matter that can interfere with treatment. |
Inorganic Substances |
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Fluoride (ppm) |
N |
0.74 |
0.60 to 0.74 |
4 |
4 |
Erosion of natural deposits; water additive which promotes strong teeth; discharge from fertilizer and aluminum factories. |
Sulfate (ppm) |
N |
30 |
23 to 30 |
not regulated |
500 [proposed] |
A mineral that occurs naturally in soils. |
Disinfection By-products |
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Total Haloacetic Acids (ppb) |
N |
31.5 (running yearly average) |
22 to 36 (individual sample sites) |
60 (running yearly average) |
0 |
By-product of drinking water chlorination. |
Total Trihalomethanes (ppb) |
N |
38.2 (running yearly average) |
32 to 49 (individual sample sites) |
80 (running yearly average) |
0 |
By-product of drinking water chlorination. |
Bromodichloromethane (ppb) |
N |
5.2 |
no range |
Not regulated |
Not regulated |
By-product of drinking water chlorination. |
Chloroform (ppb) |
N |
12.0 |
no range |
Not regulated |
Not regulated |
By-product of drinking water chlorination. |
Chlorodibromomethane (ppm) |
N |
1.0 |
no range |
Not regulated |
Not regulated |
By-product of drinking water chlorination. |
Chloramines (ppm) |
N |
3.2 (running annual average of monthly distribution system samples Jan., Feb. and April through Dec.) |
1.4 to 4.0 (range of individual distribution system samples Jan., Feb., and April through Dec.) |
MRDL = 4 |
MRDLG = 4 |
Water additive used to control microbes. |
Chlorine (ppm) |
N |
1.40 (average of distribution system samples in March) |
0.50 to 3.80 (range of individual distribution system samples in March) |
MRDL = 4 |
MRDLG = 4 |
Water additive used to control microbes. |
Disinfection By-product Precursors |
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Total Organic Carbon (ppm) - RAW |
N |
5.77 (annual average of source water) |
1.36 to 1.74 (range of Remoal Ratios) |
TT |
N/A |
Naturally present in environment. |
Total Organic Carbon (ppm) - TREATED |
N |
1.79 (annual average of filtered water) |
1.50 to 2.20 (range of Removal Ratios) |
TT |
N/A |
Naturally present in environment. |
Glossary
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 allow for a margin of safety.
Maximum Contaminant Level (MCL) - 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. MCLs are set at very stringent levels. A person would have to drink 2 liters (about two quarts) of water every day at the MCL level for a lifetime to have a one-in-a-million chance of having adverse health effects from many regulated contaminants.
Parts per million (ppm) - one part per million corresponds to one minute in two years or one penny in $10,000. One ppm is equivalent to 1 milligram per liter (mg/L).
Parts per billion (ppb) - one part per billion corresponds to one minute in 2,000 years, or one penny in $10 million. One ppb is equivalent to 1 microgram per liter (ug/L).
Nephelometric Turbidity Unit (NTU) - a measure of cloudiness in water. Turbidity over 5 NTU is just noticeable to the average person.
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.
90th Percentile - The contaminant level which 90 percent of the samples for a given water characteristic were below. The 90th percentile level is the required reporting unit for lead and copper.
Below Detectable Level (BDL) - a concentration that is below the level that can be detected with required tests.
Maximum Residual Disinfection 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 using disinfectants to control microbial contaminants.
Maximum Residual Disinfectant Level (MRDL) – The highest level of a disinfectant allowed in drinking water. Disinfection is necessary to control microbial contaminants in drinking water.
Disinfection by-products - Substances such as haloacetic acids and trihalomethanes, which are formed when chlorine or chloramines used to disinfect drinking water react chemically with organic compounds naturally present in the water from our lakes. Federal standards require public water systems to limit the level of haloacetic acids and trihalomethanes because they could be harmful at high levels.
Disinfection by-product precursors - Organic carbon compounds that can combine with disinfectants (chlorine and chloramines) to form haloacetic acids and trihalomethanes as discussed above.
Removal Ratio - Measure of the effectiveness of Total Organic Carbon removal during OWASA's treatment process. This ratio should be greater than or equal to 1.0. The Removal Ratio is the federally required reporting unit for Total Organic Carbon.
Where do contaminants come from? 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, the water 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 before it is treated include: Microbial contaminants such as viruses and bacteria, which may come from wastewater treatment plants, septic systems, agricultural livestock operations and wildlife; Inorganic contaminants such as salts and metals, which can be naturally occurring or result from 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, 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 and stormwater runoff from paved and other impervious surfaces; and Radioactive contaminants, which may be naturally-occurring or the result of oil and gas production and mining activities. What is Cryptosporidium? Cryptosporidium is a microscopic organism that can cause diarrhea, fever and other gastrointestinal symptoms. We have tested for Cryptosporidium in our reservoirs and treated water and have never detected it in our treated water or lake water. The organism comes from human and animal wastes and may occur in local streams and lakes. We control Cryptosporidium through a combination of source water protection and sophisticated treatment technology. Please contact us at 537-4227 if you would like more information about Cryptosporidium. All drinking water, including bottled drinking water, may be reasonably expected to contain at least small amounts of some contaminants. The presence of these contaminants does not necessarily pose a health risk. The Environmental Protection Agency limits the amount of certain contaminants in water from public drinking water systems. The Food and Drug Administration sets limits for contaminants in bottled water to provide the same protection for the public health. TESTING FOR LEAD: We fully comply with the Federal and State standards and testing requirements regarding lead. In some communities with old water systems, lead contamination has resulted from lead fittings or lead pipes in the network of public water mains. In the OWASA water system, however, all known lead fittings and pipes have been abandoned or removed. In the last 10 years, all lead testing results for our treated water where it leaves our Jones Ferry Road Water Treatment Plant have been below the detectable level of 1 or 3 parts per billion, depending on the year. We also test every three years for lead in tap water at 30 homes and these test results are shown in the table of Substances Found in OWASA Water. Tap water at older residences may have lead because of lead solder, fixtures and pipes were allowed in plumbing systems before 1986. To get more information including how you can have the water in your home tested for lead, please call the OWASA Laboratory staff at 537-4227 or send an e-mail to rmonschein@owasa.org. ARSENIC TESTS: In February and November of 2003, we tested for arsenic in our drinking water. The result: arsenic was below the detectable level of 5 parts per billion.
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MTBE TESTING: In April of 2005, we tested our drinking water for a substance called MTBE, which has been a component of gasoline. Test results: MTBE was below the detectable level of 0.5 parts per billion. Additional characteristics of our drinking water We disinfect our water with “chloramines,” a compound of chlorine and ammonia, in the months other than March. In March, we instead use chlorine for disinfection in accord with State requirements. Chloramines and chlorine are toxic to fish and amphibians such as frogs. If you have fish in an aquarium with OWASA water, please contact a pet supply store for advice on how to neutralize chloramines and chlorine to protect your fish. OWASA’s drinking water is very “soft”—it has a low mineral content (dissolved calcium, etc.) of about 2 grains per gallon of water. This means that a small amount of soap is needed for washing dishes, clothes, your hands, etc. Our water is slightly alkaline. On the scale of acidity to alkalinity, our water normally has a pH of about 8.3. In the month of March, we adjust the pH to about 7.4 when we temporarily use chlorine instead of chloramines to disinfect the water. The pH of our water helps make the water treatment process work effectively and helps prevent corrosion in both public water mains and private plumbing system pipes. Sometimes our water looks rusty or bubbly because work that we do on the water system may stir up iron or other minerals that have accumulated in a water main, or because air may enter water mains during a repair. Running a cold water faucet as in a bathtub, etc. for 5 to 10 minutes should clear up the discoloration. If the water does not clear up, please contact us at 968-4421. The water should be clear before washing clothes, etc. N.C. Source Water Assessment Program Results The N.C. Department of Environment and Natural Resources (DENR), Public Water Supply (PWSS) Section, Source Water Assessment Program (SWAP) has conducted assessments for all drinking water sources across North Carolina. The purpose of the assessments was to determine the susceptibility of each drinking water source to potential contaminant sources (PCSs). The results of the assessment are available in SWAP Assessment Reports that include maps, background information and a susceptibility rating of Higher, Moderate or Lower. The susceptibility rating of each water source for OWASA was determined by combining the contaminant rating (number and location of PCSs within the assessment area) and the inherent vulnerability rating (i.e., characteristics or existing conditions in the watershed and its delineated assessment area). The assesssment findings are summarized in the table below: Susceptibility of OWASA's Water Sources to Potential Contaminant Sources
The complete SWAP Assessment report for OWASA may be viewed on the Web at http://www.deh.enr.state.nc.us/-pws/swap. To get a printed copy of this report, please mail a written request to: Source Water Assessment Program -- Report Request, 1634 Mail Service Center, Raleigh, NC 27699-1634, or e-mail your request to swap@ncmail.net. Please indicate your water system name (OWASA), OWASA's public water supply number (03-68-010), and provide your name, mailing address and phone number. If you have any questions about the SWAP report, please contact the NC Source Water Assessment staff at 919-715-2633. Please note: A susceptibility rating of "higher" does not imply poor water quality, only the system's potential to become contaminated by PCSs in the assessment area.
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Where does our water come from? |
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The Carrboro-Chapel Hill community uses water from three surface water reservoirs:
Water from Cane Creek and University Lake is pumped directly to the Jones Ferry Road Water Treatment Plant in Carrboro. Water from the Stone Quarry Reservoir can be pumped to University Lake via Phil’s Creek and with pending improvements, to our water treatment plant. In addition to these sources, OWASA has water line connections with the City of Durham , the Town of Hillsborough and Chatham County .
By the year 2030, an expanded stone quarry about two miles west of Carrboro will become available to OWASA for water storage with an expected capacity of 2.4 to 3 billion gallons. OWASA has received an allocation from the North Carolina Environmental Management Commission to use Jordan Lake water in the future if needed and if pumping and transmission facilities are built. However, our policy is to maximize the use of water from our existing, high quality water sources, which are protected with locally-adopted development restrictions. |
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In 2005, we provided more than 3.1 billion gallons of drinking water to the Carrboro-Chapel Hill community in accord with State and Federal standards for safe drinking water. Our Laboratory staff tested our drinking water for more than 100 substances, but only 13 were present at detectable levels. As shown in this report, the substances we detected were below the limits under the Federal Safe Drinking Water Act. Regular testing shows that our drinking water is healthy and safe for almost everyone. However, people with weak or developing immune systems may need to take special precautions.
(Please click here to see the item on "For people with special risks of infection" for more information.)
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