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Drinking Water Quality in Mecklenburg County

 Hot Topics in Water Quality

lab services
Our expertly trained lab analysts and state-certified water treatment operators work together to deliver safe drinking water to you.  More than 100 million gallons of water are treated and distributed each day to homes, schools and businesses in our community.

We are committed to exceptional water quality that meets or surpasses all required water quality standards.

Our success is reflected in the results of more than 150,000 tests which are performed annually during and after the treatment process. The quantity of tests we conduct also far exceeds requirements. 

 If you have a water quality concern or emergency, please call 311 or 704.336.7600. 

Water Treatment Questions

Blog article about water treatment

How is Drinking Water Treated?
What is the quality of our drinking water

Why is pH important?
Why is dissolved oxygen monitored?

Why is there chlorine and fluoride in our water?
How can I remove the chlorine taste?

Is our water hard or soft

Are bacteria in our drinking water? 
What is Cryptosporidium? 

How is our water protected from threats?

Water Quality Questions

Blog article about water quality

What causes my water to be discolored? 
I detect an odd taste or odor.  Is it the water?

My water has a yellow or red tint. What is it? 
Why does my water look cloudy / milky

What are the pink stains on fixtures and drains?
Why does my hot water smell like rotten eggs

Why is a company asking to test my water?

Is lead found in our water?
Will flushing hydrants affect water service? 

Where can i find the annual water quality report?



Why is pH important?
If drinking water is too acidic, it will begin to dissolve the pipes that bring the water to your house. The pH scale goes from 0-14. If the pH of a solution is less than 7, the solution is an acid. If the pH is greater than 7, the solution is a base.

     Examples of acids: lemon juice and vinegar
     Examples of bases: baking soda and soapy water.

     The pH of our water is maintained between 7.8 and 9.2. It is a base.

Why is dissolved oxygen monitored?
Dissolved oxygen is important because fish need it to breathe. The water treatment plant monitors the dissolved oxygen level of incoming lake water.

Why is there chlorine and fluoride in our water?
Chlorine is added to kill bacteria and prevent waterborne illness, and fluoride provides a defense against tooth decay. Both of these substances are added to water during the water treatment process. Our drinking water typically contains 0.2 milligram per liter (mg/l) - 1.6 mg/l of chlorine.

Fluoride has been proven to promote oral health. Charlotte Water (CLTWater) has added fluoride to our water since 1949. Fluoride is added to CLTWater tap water at a concentration of approximately 0.7 milligram per liter or less than 1 part per million, as recommended by the American Dental Association.

Fluoride is a mineral that occurs naturally in virtually all waters. It is present in seawater at levels between 1.2 to 1.4 mg/L and in surface waters from 0.1 to over 1.0 mg/L, and can be found in some ground water over 10 mg/L. 

On April 15, 2011, CLTWater Officials scaled back fluoride under guidance from Mecklenburg County Health Department. Learn more from Dr. Keener, Director of Mecklenburg County Department of Health.

Other resources:

North Carolina Position Statement on

US Department of Health and Human Services 

Environmental Protection Agency (EPA

Centers for Disease Control and Prevention (CDC)

Can I remove the chlorine taste in my tap water?
Yes. Chlorine dissipates over time so fill a pitcher and place it in your refrigerator. 

Is our water hard or soft?
Hardness is primarily a measurement of calcium and magnesium concentration. Water is considered hard if it measures more than 125 parts per million, or 7.5 grains per gallon of trace minerals. Our water has a hardness measure of 30 parts per million, or 1.8 grains per gallon, which is considered soft. 

What causes my water to be discolored?                                    back to top
While the clean water delivered to you is normally clear, occasional pressure changes or fire hydrant use can cause discoloration due to mineral sediments in water pipes. If you experience a problem with colored water coming from your tap, first run your cold water tap for five minutes. The color will most likely go away. If the water is still discolored, call 311 or 704-336-7600.

-If your HOT water is discolored, you may have a water heater problem. One way to determine whether the problem is in the hot or cold water is to see if the discoloration exists in your toilet bowl. If the toilet bowl water is not discolored, then the discoloration is likely in the hot water or your home’s plumbing. This is a private plumbing problem and CLTWater recommends that you review owners manual or contact a licensed plumber for advice.

Why are there pink stains on my fixtures and drains?
These pink stains are usually caused by airborne microorganisms which settle and grow where there is moisture.  Pink stains are “most likely from the environment and not the water supply” (reference: Water Quality Investigator’s Field Guide (2005) American Water Works Association.)  it is extremely important to regularly clean these areas which should temporarily remove the stains.

I detect an odd taste or odor. Is it in the water?
Taste and odor changes in your water can occur for many reasons. They do not always indicate a change in the safety of your water. Water taste is affected by mineral content as well as the presence of chlorine. Sometimes a metallic flavor can be caused by your plumbing, especially if the water tap has not been turned on for several hours. Newer homes with PVC (plastic) pipes may also experience temporarily altered taste or odor.

If you experience a problem with the taste or odor of your water, let the COLD water (through bathtub spout) run for a few minutes to clear the lines, or fill a pitcher and allow it to sit for several hours. If the problem persists, please call 311 or 704.336.7600.

One of the main causes of taste/odor problems involves garden hoses being left attached to external faucets. This can allow tastes/odors from the garden hose to be noticed in the tap water you drink. CLTWater recommends that garden hoses be disconnected when not in use.  If you have a taste/odor problem, please detach your garden hose first. If the taste/odor is still present 24 hours after you detached the garden hose from external faucets, please call 311 or 704-336-7600.

Why does my hot water smell like rotten eggs?                                                   back to top
If you only notice an odor in hot water, your water heater may need to be checked by a plumber.  Some water heaters have magnesium anodes to prevent corrosion that can cause an odor in tap water. Other odor sources may include food or a blockage in the garbage disposal or a drain.  

Why is a company asking to test my water?                                                        back to top
Several private companies hang surveys and small sample bottles on residential doors with the offer to conduct water quality tests. 

These tests are not associated with CLTWater or any other City or County Department. If you have any questions about, or issues with, your tap water quality, please contact 311 or 704-336-7600. 

You may also look at the Water Quality Report for more information.   Also a consumer warning is posted here.

My water has a yellow or red tint to it.  What is it?
A yellowish tint is possible if the water is sitting in the pipe for a long time (i.e. winter or a long vacation).  While the water is waiting to be used, it can collect dissolved iron sediment from older pipes.  An increase in this mineral causes water to change color but doesn’t affect the safety of the water.  Run COLD water (through bathtub spout) for several minutes to clear.  

Over several years, minerals and sediment can build up inside water pipes.  Reddish water can occur, for example, when a fire hydrant is quickly turned on and off. Run COLD water (through bathtub spout) for several minutes to clear.  

Every year CLTWater invests millions of dollars to replace or reline pipes in the oldest parts of Mecklenburg County and in places where discoloration repeatedly occurs.

Why does my water look cloudy / milky?
Sometimes water appears cloudy or milky because air is trapped inside the water pipe, causing excess bubbles.  You should let the water sit in a container, the bubbles will dissipate over time.  If it continues, run your COLD water (through bathtub spout) for several minutes.

Are there bacteria in our drinking water?                                                                        back to top
CLTWater treats water with chlorine to kill any harmful bacteria.   

Is lead found in our water?
Lead is not in the water supplied by CMUD. 

The plumbing inside some older homes may contain lead which can cause lead to be present in tap water at those locations. Concentrations may be elevated particularly after the water is unused for an extended period of time. Allowing the faucet to run for a few minutes before using the water should reduce lead levels.

Will flushing hydrants affect water service?                                                                     back to top
Sometimes crews flush water to maintain water quality or test the hydrants.  While the hydrants are flushing you may see lower than usual water pressure, but it will be restored when flushing ends.

What is Charlotte-Mecklenburg doing to protect our water from threats?
Your water is safe to drink and all reasonable steps are in place to protect the public water system. Water quality control has been an everyday part of our mission long before 9/11/2001. 

While security details aren’t something we discuss publicly, they are a vital part of our operating procedure. CLTWater continually enhances security measures and participates in emergency preparedness exercises with state and federal agencies. We will take all appropriate steps to ensure continued delivery of safe and sufficient drinking water.

What are Cryptosporidiumand Giardia                                                                         back to top
Cryptosporidium and Giardia are microscopic parasites sometimes found in untreated surface waters. If ingested, either can cause gastrointestinal illness. CLTWater tests for these parasites.

Pharmaceuticals / Prescription Drugs and Water

Keep your pipes clear, and our water safe. 
When cleaning out your unused medications, be sure to properly dispose of them and protect our water supply.
* Prescription and over-the-counter medications should be disposed of in the trash.
* Dissolve pills in water and mix with kitty litter.  Put this in a secure lidded container in your trash.
* Never flush medicines, grease, oils, diapers, wipes, or other objects.

Pharmaceuticals are an emerging concern that the water industry has been researching for several years, but one that is not yet well understood. We know the human body often only absorbs small amounts of the various prescription and over the counter medicines and dietary supplements that are widely used.

The parts of these medications and supplements that are not absorbed naturally pass through the body and flow into wastewater treatment plants. While some of the pharmaceutical compounds may be removed or reduced by the wastewater treatment processes, at least some of them may pass through the plant and are discharged into streams, rivers, and groundwater (via septic systems) across the country. Those streams and rivers are used as water supply sources by other communities downstream. The drinking water treatment process may remove or reduce some pharmaceutical related contaminants, but not necessarily all of them.

The US EPA has not established standards to regulate the amount of pharmaceuticals in drinking water, at least in part because the effects of low dosages over time are not yet known. Neither the EPA nor state drinking water regulators have established requirements for testing drinking water for these types of contaminants.

There are very few laboratories in the country that are capable of analyzing water samples for a full spectrum of pharmaceutical compounds. Research supports that the concentrations found in those few samples that have been tested are very, very low - far below prescribed medical dosages.

CLTWater runs more than 150,000 water quality tests per year for more than 100 substances in accordance with state and EPA regulations. We have not tested Charlotte's water supply for pharmaceuticals, but we support professional research in that area through our membership in the American Water Works Association Research Foundation and the Water Environment Research Foundation. If Charlotte were to test for pharmaceuticals, it is likely some types would be detected at very low concentrations, simply because they seem to be pervasive in the environment and because today's sophisticated laboratory processes can detect tiny quantities.

Charlotte will continue to follow the research and to work with N.C. drinking water regulators and health officials to be sure that our drinking water is safe for our customers. Customers who have questions about what is in their tap water are encouraged to visit the water quality report section of or call the EPA safe drinking water hotline at 1-800-426-4791.

Link to EPA information.

Ranking Best or Worst Tap Water
CLTWater disagrees with any group's subjective analysis no matter if it ranks us favorably or not. Public water providers are not easily compared or ranked since water supply and other factors can vary greatly.

Key Facts about CMUD water quality:

     * Our drinking water meets and exceeds all state and federal drinking water standards.
     * More than 150,000 water quality tests each year (including in public areas like restaurants and stores)
     * More than 150 different substances tested (most occur naturally)
     * 100 million gallons of water delivered each day
     * Expertly trained lab analysts and state-certified water treatment operators
     * CLTWater had a monitoring error and a testing error that lead to a notice of violation in 2004 and 2005 respectively.
     * CLTWater has not had any violations that would impact water quality or customers.

Customers who are interested in the facts about our drinking water should click here to view past water quality reports.

Beware of Products Claiming to Reduce Water Bill,
Provide Free Water Quality Testing

* CLTWater encourages customer to research and verify before purchasing products that claim to reduce water bills or remove 'impurities.'

* Customers can find general tips and alerts at the Better Business Bureau web site (
Beware of false or misleading information about Charlotte-Mecklenburg's water quality:

* No City or County staff goes door-to-door to sell anything. If a CMUD employee comes to your door for water testing purposes, he/she should be wearing identification and driving a white, marked City vehicle.

* Individual tastes will vary and some customers choose to install filters for that reason. However, tap water delivered to customers meets and often exceeds all health and safety standards and does not require additional filtration at home. CMUD conducts more than 150,000 water quality tests annually to monitor the safety of our community's drinking water. It's conceivable - but not often - that private plumbing issues could impact a customer's tap water quality.

* Tap water is not acidic. The pH scale ranges from 0 to 14. A reading of 7 is neutral, with acids falling below 7 and bases above 7. CMUD adjusts the pH of tap water to slightly above 7 to reduce corrosion in water pipes.

* Chlorine is used in the treatment process to prevent waterborne illness, while fluoride provides a defense against tooth decay. The Environmental Protection Agency regulates drinking water and has set a safety limit of 4 parts per million (proportional to $0.04 in $10,000). In Charlotte, chlorine and fluoride levels in drinking water are well below that safety limit at about 1 ppm.

* Water hardness is defined by the amount of trace minerals present, such as calcium and magnesium. Water is considered 'hard' if it has more than 125 parts per million of trace minerals. Charlotte's tap water has an average of 34 ppm or 1.8 grains per gallon of trace minerals, so it is considered 'soft' water.

The safety of our customers' drinking water is the top priority for your clean water professionals at CLTWater. Customers can dial 311 or 704-336-7600 if they have a water quality concern.

Other Resources:


Bottled Water and Tap Water

Click on links to American Water Works Association tap water and bottled water information.
Link to EPA website about drinking water.



Questions About Coal Ash and Water Quality
The source of Charlotte’s water is the Catawba River at Mt. Island Lake and Lake Norman. CLTWater converts lake water into drinking water that is safe to drink because it is treated and tested more than 150,000 times a year at the water treatment plants and throughout the community.
Duke Energy announced their plan to remove coal ash from the Riverbend power plant. Coal ash has been at this location on the Catawba River for more than 50 years. Coal ash has not caused a challenge for drinking water treatment because water plants typically pull water from the middle of the lake instead of from the bottom where sediment, pollution, and debris settle. Duke Energy’s activities at Riverbend should not cause a drinking water challenge, but Charlotte-Mecklenburg Utility Department will increase water quality testing just as a precaution. In the rare event of something happening, our existing facilities and processes are in place to provide safe drinking water.
Whenever we have a water quality concern we immediately inform customers in the area and fix the problem. These situations are very rare because the lakes allow debris to settle, our water treatment process is award-winning, and our staff is vigilant to deliver a safe product to customers and their own families.