Source and Treatment of Your Drinking Water

The source of your drinking water is groundwater under the direct influence of surface water from the Chilhowie/Washington County Service Authority Regional Water Treatment Plant, surface water treated at the Washington County Service Authority Middle Fork Holston River water treatment plant and groundwater from the Washington County Service Authority Reservation Spring. Treatment includes filtration, chlorine disinfection, and fluoridation.

A source water assessment of our system was conducted in 2001, 2002, and 2019 by the Virginia Department of Health, the Washington County Service Authority and a private consulting agency. The Reservation Spring, Widener Spring, Jones Spring, Middle Fork of the Holston River and the South Holston Lake were determined to be of high susceptibility to contamination using the criteria developed by the state in its approved Source Water Assessment Program. Additional information concerning this report may be obtained by calling the Town of Chilhowie at the number listed above.


Contaminants in your drinking water are routinely monitored according to Federal and State regulations. The table on the next page shows the results of our monitoring for the period of January 1st to December 31st, 2019. In the table and elsewhere in this report you will find many terms and abbreviations you might not be familiar with. The following definitions are provided to help you better understand these terms:

Maximum Contaminant Level, or 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.

Maximum Contaminant Level Goal, or 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.

Non-detects (ND) - lab analysis indicates that the contaminant is not present

Parts per million (ppm) or Milligrams per liter (mg/l) - one part per million corresponds to one minute in two years or a single penny in $10,000.

Parts per billion (ppb) or Micrograms per liter - one part per billion corresponds to one minute in 2,000 years, or a single penny in $10,000,000.

Parts per trillion (ppt) or Nanograms per liter (nanograms/l) - one part per trillion corresponds to one minute in 2,000,000 years, or a single penny in

Picocuries per liter (pCi/l) - picocuries per liter is a measure of the radioactivity in water.

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.

Nephelometric Turbidity Unit (NTU) - nephelometric turbidity unit is a measure of the clarity, or cloudiness, of water. Turbidity in excess of 5 NTU is just noticeable to the average person. Turbidity is monitored because it is a good indicator of the effectiveness of our filtration system.

Maximum Residual Disinfectant Level Goal or MRDLG — the level of 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.

Maximum Residual Disinfectant Level or 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.

Level 1 assessment - a study of the water system to identify potential problems and determine (if possible) why total coliform bacteria have been found in our water system.

Level 2 assessment - a very detailed study of the waterworks to identify potential problems and determine (if possible) why an E. coli PMCL violation has occurred and/or why total coliform bacteria have been found in our water system on multiple occasions.


WATER QUALITY RESULTS I. Regulated Contaminants

Contaminant (units)MCLGMCLLevel


ViolationRangeDate of Sam leTypical Source of Contamination
Nitrate (ppm)10101.390.09-1.392019Runoff from fertilizer use; Leaching from septic tanks sewage; Erosion of natural de sits
Fluoride (ppm)440.66ND - 0.662019Water additive which promotes strong teeth
Barium (ppm)220.038N0.024 -2019Discharge of drilling wastes; Discharge from metal refineries Erosion of natural de posits
Combined Radium (pCi/l)51.40.5-0.82014Erosion of Natural Deposits
Alpha Emitters (pCi/l)151.4ND — 1 42014Erosion of Natural Deposits
Chlorine (ppm)MRDLG - 4MRDL -41.51N1.50-1.602019Water additive used to control microbes
Total Organic CarbonIT met when 211.002019Naturally resent in the environment
Haloacetic Acids (ppb)6016ND — 4 92019By-product of drinking water disinfection
T"THMs [Total Trihalomethanes] (ppb)80192.3- 152019By-product of drinking water disinfection
Turbidity (NTU)TAT, 1 NTU Max0.120.01 -0.122019Soil runoff
TT, so.3 NW

95% of the time


Il Lead and Copper

Contaminant (units)MCLGAction


PercentileDate of Sampling# of Sampling Sites

Exceeding Action Level

Typical Source of Contamination
Lead (ppb)20181Corrosion of household plumbing systems; Erosion of natural deposits
Copper (ppm)1.3AL 1.30.462018Corrosion of household plumbing systems; Erosion of natural deposits; Leaching from wood preservatives
Monitoring Results for SodiumUnregulated-No Limits Designated
Level Detected unitSample DateTypical SourceGuidance
6.08 (mg/L)

Range: 1.16-3.08 mg/L

2019Naturally Occurring; Addition treatment chemicals/processesofFor individuals on a very low sodium diet (500 mg/day), EPA recommends that drinking-water sodium not exceed 20 mg/L.

Should you have a health concern contact our health care provider.

NameReported LevelRange
Unregulated Contaminant Monitoring* 2018
Aggregate Organic

Compounds Total Organic

Carbon (ppb)

Manganese (ppb)58
Bromochloroacetic Acid (ppb)
Bromodlchloroacetic Acid (ppb)
Dichloroaoetic Acid (ppb)
Trichloroacetic Acid (ppb)129.112
  • Unregulated contaminants monitoring helps EPA to determine where certain contaminants occur and whether it needs to regulate those contaminants.

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 presented in the above tables, though accurate, is more than one year old.

MCL's are set at very stringent levels by the U.S. Environmental Protection Agency. In developing the standards EPA assumes that the average adult drinks 2 liters of water each day throughout a 70-year life span. EPA generally sets MCLs at levels that will result in no adverse health effects for some contaminants or a one-in-ten-thousand to one-in-a-million chance of having the described health effect for other contaminants.

Violation Information - Your water system did not have any reporting, MCL or IT violations during 2019.

Additional Information for Lead

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in dinking water is primarily from materials and components associated service lines and home plumbing. The Town of Chilhowie 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 two 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 (800-426-4791).