2016 Water Quality Report

Columbia’s Water Exceeds Standards

Columbia’s water is tested more frequently and more thoroughly than is required by the EPA and the Missouri Department of Natural Resources. The well water is monitored for any possibility of contamination by more than 4,000 tests are run each year on samples from 41 locations throughout Columbia. 

This Water Quality Report is required by the EPA’s Safe Drinking Water Act and lists only those substances found in measurable quantities in Columbia’s drinking water during 2015.  Columbia Water & Light also reports any events that might compromise the water quality to the Missouri Department of Natural Resources (see 2015 list of events).  

Source of Columbia’s Water

Columbia’s water is pumped from wells that tap a water-filled bed of sand and gravel beneath the farm land bordering the Missouri River just southwest of the city in McBaine. Long ago, melting glaciers washed sand, gravel and boulders downstream, leaving thick deposits along the course of the river. This geological formation is an alluvium, which, when saturated with water, becomes an alluvial aquifer. Water moving slowly through the aquifer is replenished by a combination of groundwater that flows down from higher elevations and water from the Missouri River that migrates through the formation.

In the area surrounding Columbia’s 15 wells, 44 billion gallons of water fill the aquifer. The wells average 110 feet in depth, penetrating the aquifer to near its bottom. Collectively, the wells can pump about 21,000 gallons of water per minute, or 30 million gallons per day to Columbia’s 100,000-plus residents.

Groundwater pumped from the wells is piped to the Columbia Water Treatment Plant. The water is naturally of very high quality and free of harmful chemicals and bacteria. However, it does contain dissolved calcium and magnesium that require it to be softened before use. At the treatment plant, a process called aeration oxidizes the iron and strips out the hydrogen sulfide to reduce these levels.

The water treatment plant’s staff disinfects the water with chlorine, and then adds ammonia to combine with chlorine forming chloramine. Customers who are undergoing dialysis or have pet fish need to remove the chloramine prior to use in dialysis equipment or in aquariums. Softened, filtered, and disinfected water is then pumped from the treatment plant to reservoirs at Columbia’s three pump stations. The water is then pumped throughout the city to consumers.

Source Water Assessment

The Department of Natural Resources conducted a source water assessment to determine the susceptibility of our water source to potential contaminants. Assessment maps and summary information sheets are available at http://drinkingwater.missouri.edu/swip/swipmaps/pwssid.htm. Enter the ID code 3010181 to access the maps for Columbia’s water system.  Download Columbia’s 2013 Source Water Protection Plan  or call 573-874- 2489 to request a copy.

Water Testing Results

(of substances found in measurable quantities)

Unregulated Substance (units) Reported
Chloroform (ug/L) 20.4

8.06 – 41.9

Bromodichloromethane (ug/L) 15.72 8.8 – 27.7
Dibromochloromethane(ug/L) 11.24 7.22 – 16.1
Bromoform (ug/L) 1.91 1.27 – 2.23
Sulfate (mg/L) 86.33 41.5 – 125
Hex Chromium (ug/L)* 1.3 1.2 – 1.3
Molybdenum (ug/L)* 2.44 1.6 – 2.4
Strontium (ug/L)* 175 162 – 175
Vanadium (ug/L)* 1.05 0.91 – 1.05

Regulated Substance (units) and the major source(s) of regulated substance
Reported Concentration
Barium (mg/L)
Discharge of drilling wastes; Discharge from metal refineries; Erosion of natural deposits
2 2 0.123
Combined radium (pCi/L)
Erosion of natural deposits
0 5 1.4*
Copper (mg/L)
Corrosion of household plumbing systems
1.3 AL=1.3 0.040 (1)
Fluoride (mg/L)
Erosion of natural deposits; Water additive that promotes strong teeth
4 4 0.58 (2)
Lead (ug/L)
Corrosion of household plumbing systems
0 AL=15 2.63 (3)
Radon (pCi/L)
Erosion of natural deposits
0 300 (4) 50.4* (4)
TTHM (ug/L)
By-product of drinking water chlorination
0 80 49.9 (5)
HAAs (ug/L)
By-product of drinking water chlorination.
0 60 21.5 (6)

Nitrate – Nitrite (mg/L)

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

10 10 0.0252

Total Chlorine (mg/L)
Water additive for disinfection

4 4 2.57 (7)
Total Chromium (ug/L)
Discharge form steel and pulp mills
100 100 0.094

* Indicates data from a previous year’s monitoring.

View the full 2015 Water Testing Results.


1. Fifty distribution samples were checked for copper. None of the samples exceeded the copper action level. The measurements ranged from 0.013 to 0.199 mg/L.

2. Reported concentration of fluoride is the average of twelve samples. The range of measurements is 0.2 to 0.65 mg/L.

3. Fifty distribution samples were checked for lead. One customer sample exceeded the lead action level. The measurements ranged from undetected to 36.3 μg/L. Compliance is determined by the 90th percentile which was 2.63.

4. Radon in drinking water at the MCL of 300 pCi/L poses an estimated increased risk of an additional 2 cases of cancer for every 10,000 people exposed. Increased cancer risk for the levels found in our water, 50.4 pCi/L, are undetermined. Additional information is available at the EPA website: epa.gov/radon/rnwater.html.

5. Reported concentration of TTHM is the average of 24 samples from the distribution system. The range of measurements is 33.8 to 87.9 μg/L.

6. Twenty-four samples were checked for HAAs. The range of measurements is 12.1 to 35.7 μg/L.

7. Reported concentration of total chlorine is the average of 1,454 samples collected throughout the year at 10 different places in the distribution system. Measured concentrations ranged from 0.47 mg/L to 3.80 mg/L.

MDRL—Maximum Disinfectant Residual Level: 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.

MDRLG—Maximum Disinfectant Residual Level Goal: The level of a drinking water disinfectant below which there is no known or expected risk to heath. MDRLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

MCLG—Maximum Contaminant Level Goal: The level of a contaminant in drinking water below which there is no known or expected risk to health. Allows for a margin of safety.

MCL—Maximum Contaminant Level: The highest level of a contaminant that is allowed in drinking water. Set as close to the MCLGs as feasible with the best available technology.

pCi/L—Picocuries Per Liter: A measure of radioactivity.

mg/L—milligrams per liter or parts per million.

AL—Action Level: The concentration of a contaminant which triggers a treatment or other requirement which a water system must follow.

μg/L—micrograms per liter.

Messages from the Environmental Protection Agency

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 Environmental Protection Agency’s Safe Drinking Water Hotline (800-426-4791). Contaminants that may be present in source water include:

  1. Microbial contaminants, such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife.
  2. 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.
  3. Pesticides and herbicides, which may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses.
  4. 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.
  5. Radioactive contaminants, which can be naturally-occurring or be the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the Department of Natural Resources prescribes regulations which limit the amount of certain contaminants in water provided by public water systems. Department of Health regulations establish limits for contaminants in bottled water which must provide the same protection for public health. 

Immuno-compromised People

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised people with cancer undergoing chemotherapy, people 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. EPA and Centers for Disease Control guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline, 800-426-4791.

Lead and Copper Notice

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. Columbia 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 (800-426-4791) or at http://water.epa.gov/drink/info/lead/index.cfm

Columbia Water & Light is a publicly run utility. Any citizen interested in learning more about water quality or wishing to express an opinion regarding our water system can do so by the following means: meetings of the City Council and Water & Light Advisory Board; through the Manager of Water Production, Mike Anderson, at 573-445-3517 or wlmail@como.gov.

The information on this page is from the annual Columbia Water & Light Water Quality Report published each spring for the previous year’s testing results. The content is created under guidelines set forth by the U.S. Environmental Protection Agency (EPA) for the Consumer Confidence Report.