Category Archives: Water Quality

Chlorine And Your Drinking Water

To ensure harmful bacteria does not grow during the sometimes very long trip from the treatment plant to your home,  we add a very small amount of chlorine to keep the water disinfected and safe to drink.

Your water averages about 1.3 parts per million (ppm) of chlorine when it leaves the treatment plant and about 1.16 ppm in the distribution system. The EPA maximum contaminant level is four ppm.

For scale, one ppm is equal to a single penny in $10,000 or one drop of water in a ten gallon tank. Still can’t imagine it? Check out this cool TedEd video about how to visualize one ppm.

Our field staff use chlorine as an indicator of good water quality. When they are out in the field taking samples and the chlorine levels are good, they can be sure that there is no bacteria in the line or in your drinking water.


Below are the results from testing in 2022 and are shown in our annually produced Consumer Confidence Report.

Taste can differ and those that live closer to a drinking water treatment plant may taste more chlorine in their water than those that live farther away. Remember, 1.3 ppm of chlorine disinfects the water but is not harmful. If you don’t like the taste we suggest filling a pitcher up with tap water up and letting it sit overnight. If you use a filter please make sure to replace it regularly!

What Causes High Water Pressure and How Do I Fix It?

If you are reading this, you probably had a recent visit from a plumber.

Did you know:

  • Water pressure is primarily due to the elevation of storage tanks relative to the elevation of your home. 
  • Higher water pressures are in geographically low points (near a creek or the bottom of a neighborhood).
  • County building codes require pressure-reducing valves (PRVs) to be installed on new or remodeled residential plumbing if there is evidence of water pressure exceeding 80 psi.
  • You can buy a gauge at a home improvement store to check your pressure.
  • A PRV reduces the water pressure coming into your home to protect your plumbing, much like an electrical surge protector protects your computer or television.
  • Keep in mind that a PRV will age and need to be replaced. So if you notice a sudden increase in pressure in your plumbing, your PRV may be wearing out and needs to be replaced.
picture of a pressure reducing valve or PRV.

Frequently Asked Questions

Why should I care if my water pressure is more than 80 psi?

​High water pressure could cause:

  • Appliances and fixtures fail sooner than average
  • Damage water heater
  • High repair and water bills 

How would I know if I have high water pressure?

If you are experiencing any of the below situations, it is time to talk to a plumber: 

· A leaking faucet or appliance may tell you it is wearing down, and water pressure should be checked. 

· A toilet flowing water from the tank into the bowl when not in use (could also be a simple toilet repair).

· Water is spitting instead of flowing when the faucet is first turned on.

· The sound of pipes banging inside the house may note pressure fluctuations.

· Irregular changes in pressure in shower or sinks.

· Appliances failing early.

· Mineral deposit build-up (white or greenish) on the outside of a shutoff valve. 

Check with your neighbors – It may be possible that your neighbors are experiencing a similar issue. If they are not, this may indicate a problem with your private plumbing. 

What should I ask the plumber about high water pressure and pressure-reducing valves?

​A licensed plumber can assess your current plumbing and recommend whether a PRV is needed. Remember, getting more than one price quote is always a good idea.

  • Some contractors / licensed plumbers may choose to use an expansion tank (also known as a bladder) or other options to discharge high water pressure safely out of the plumbing system. 
  • A PRV can be installed three feet behind the water meter box or inside your home before the water heater.
  • Avoid installing PRVs in sidewalks or driveways. 
  • Please be sure your plumber clearly explains any warranty that may apply to the PRV and the plumber’s work.
  • PRVs will eventually need to be replaced between 7 and 12 years typically.
    • Note: If your water pressure noticeably changes, It may be time to replace the PRV.

​What if the PRV makes the water pressure too low?

· PRVs are adjustable

· Consider replacing old fixtures or pipes that may be clogged with mineral deposits

Can Charlotte Water (CLTWater) reduce the water pressure in my home?

A licensed plumber can check your pressure and determine if you need a PRV.

Customers are in water pressure zones that serve several zip codes to provide minimal pressure of 20 psi to fire hydrants for public safety. CLTWater rarely changes water pressure zones. In those rare cases, a water pressure zone is changed to help customers experiencing low water pressure.

Does water pressure fluctuate daily?

​Water pressure will vary throughout the day. Based on elevation and other factors, your home has a water pressure range that varies a few psi. You are more likely to experience the following:

  • The low range of water pressure during summer mornings when irrigation use may be high in the neighborhood
  • The high range of water pressure typically from December through February when outdoor water use is minimal

Will the City of Charlotte pay for my PRV or plumbing costs caused by water pressure?


I have 80+ psi and no PRV. Why didn’t my house have a PRV installed earlier?

​When houses are built or remodeled, the water pressure should be checked. If it is over 80 psi at the time of the test, a PRV is required. The test could have been conducted at a time of day when water pressure didn’t exceed 80 psi due to other factors (water usage, etc.).

Would Charlotte Water increase my pressure?

​Changing water pressure zones is extremely rare. Most properties have been in the same water pressure zone for several decades.

If CLTWater determines that customers need to move to a different water pressure zone, you would be notified several times in advance. 

Is the water or wastewater project nearby going to increase my water pressure?

Wastewater projects won’t have any impact on drinking water pipes or pressure.

Water projects may enhance flow and stabilize pressure by cleaning or replacing old pipes. Adding larger pipes may increase water storage in the area but will not significantly affect water pressure since most water pressure is the elevation difference between the storage tank and your home.

Where does my private plumbing start?

​The property owner maintains a water pipe from the end of the meter box (including the tailpiece) to the building(s). The property owner is responsible for pipes and fixtures in the buildings and wastewater pipes until the edge of the street or street right-of-way (varies). Charlotte Water maintains the water meter up to and including the meter yoke assembly, meter box, and water and wastewater pipes under the public street.

The illustration shows that Charlotte Water maintains the water pipes under the public streets and service lines from the water main to the meter box. Charlotte Water also maintains the meter and meter box. The property owner’s private plumbing starts at the tailpiece or pipe that leaves the water meter box and piping under the private plumbing to the building and inside the building.

Does my plumbing need to be replaced?

Just as pipes under the street age and have an end of service, so does plumbing in your home. Consider planning for the eventual replacement of plumbing that exceeds 50 years.

Learn more:

Charlotte Water Pressure

Homeowner’s Responsibility (Where Does Private Plumbing Begin?)

Water Service Replacement

Fixing At Home Leaks

Water Conservation Tips

How Do Water Towers Work?

Unidirectional Hydrant Flushing

Charlotte Water clears mineral deposits (sediment) from water pipes by flushing water through fire hydrants. The mineral deposits in the pipes are only dislodged when the water is flowing at very high speeds. It has not affected water quality but may have reduced water pressures and pipe capacity.

Water quality sampling stations (green boxes) are installed in the neighborhood so staff can test the water before and after flushing hydrants.

Customers receive a postcard and a notice on their door before this type of hydrant use. Updates will be posted on NextDoor.

Discolored Water is Possible

Customers near flushing may notice temporarily discolored water and lower than normal water pressure. The discoloration does not pose a health risk. However, avoid using tap water or running the washing machine or dishwasher until flushing is complete.

If you experience some discoloration in your water from nearby flushing, run the cold water at one tap for 5 minutes to see if it clears. If it does not clear wait an hour and try again. When the water runs clear, flush any taps where discolored water was present. If not clear after one hour, call 311 to report issues

If you have a question about this project, please contact us at 311 or 704-336-7600.

Fire Hydrant Unidirectional Flushing Frequently Asked Questions

What is unidirectional flushing?

Unidirectional flushing is used to improve and maintain our high-quality drinking water. Sediments and mineral deposits in the pipes can discolor drinking water. The high-speed water flows used in unidirectional flushing is an efficient and cost-effective way to remove sediments and deposits from the pipes and prevent potential water quality issues.
Why does Charlotte Water flush drinking water pipes?

Drinking water pipes need to be flushed out to improve water quality. Over time, very fine sediment from mineral deposits and organic matter settle out of the water and accumulate in the bottom of the pipes. While the sediments are generally harmless, they can make the disinfectant in the water less effective. Additionally, sudden changes in the flow of water can disturb these sediments resulting in cloudy, discolored water.

What should customers expect to see?

While crews have the hydrants open, passersby may notice a lot of water running down the road to a nearby storm drain. At times, the water may be very cloudy or brownish.

Is it common to flush the pipes?

Charlotte Water uses three techniques to clean and maintain the drinking water system: spot flushing, auto flushing, and unidirectional flushing.

Spot flushing is used to address discolored water issues. This includes when drinking water is discolored due to a disturbance in the system such as construction or other hydrant activity. Crews open fire hydrants to flush this water out of the system and bring fresh water into the pipes.
Auto-flushing is similar to spot flushing and is used to maintain water quality by reducing the water age in the distribution system. This type of flushing uses an automatic flushing device, called an auto-flusher, which is connected to hydrants and programmed to flush water at certain time intervals and flow rates. Using an auto-flusher reduces the amount of staff time needed to maintain consistently better water quality at a certain location in the distribution system while using water in a more efficient manner.

Unidirectional flushing is not used in response to a specific water quality issue but instead is used as routine maintenance to prevent problems from arising. The goal of unidirectional flushing is to clean the insides of the water delivery pipes. Cleaning the pipes removes sediment that builds up in the pipes. This reduces the potential for water quality problems. Unidirectional flushing works by forcing water in the pipes to flow at much higher speeds than normal. Flushing crews first open and close valves to isolate sections of pipe, and then the water and any mineral sediments in the pipes are flushed out through an open fire hydrant.

Has the sediment built up in the pipes harmed me?

The sediment from mineral deposits in the pipes is only dislodged when the water is flowing at very high speeds. It has not impacted water quality but may have impacted water pressures and pipe capacity.
Unidirectional flushing will have minimal impacts to customers. If you see hydrant flushing crews working in the area, please drive carefully and treat them like any other road construction crew.
Customers in the immediate vicinity of flushing may notice temporarily discolored water and lower than normal water pressure. The discoloration does not pose a health risk. However, avoid using tap water or running the washing machine or dishwasher until flushing is complete.
If you experience some discoloration in your water from nearby flushing, run the cold water at one tap for 5 minutes to see if it clears. If it does not clear wait an hour and try again. When the water runs clear, flush any taps where discolored water was present. If not clear after one hour, call 311 to report issues.

Why is My Water Bubbly, Cloudy, or Discolored? What is Turbidity?

A little bubbly water may catch you by surprise, but don’t worry. We didn’t change your tap to champagne. Sometimes air can get trapped inside pipes and cause temporary bubbles in a glass of water. If you notice cloudy or discolored water, it may be mineral deposits.

Very fine sediment from mineral deposits settles out of the water and accumulates in the bottom of the pipes over several years. The mineral deposits in the pipes can be dislodged during sudden changes in the direction or flow of the water (i.e., water main break, hydrant use, etc.).

CLTWater notifies water billing customers of planned and unplanned water outages as soon as possible. If you rent, you can sign up to receive alerts at If you are notified of a water outage, please turn off dishwashers, washing machines, and automatic ice machines until water service is restored.

Once water service is restored, you shouldn’t experience bubbly, cloudy, or discolored water. If you do, please:

  • Run cold water for 10 minutes (preferably an outside spigot or bathtub first).
  • When water runs clear, run cold water through any faucets where discolored water is present.
  • If the water isn’t clear, run cold water for an additional 10 minutes and carefully unscrew faucet aerators to remove and clean.
  • If water is not clear, please call 311 or 704-336-7600 and say or select water emergency.

Turbidity is the measure of the cloudiness of the water and is a key water quality measurement taken at our treatment plants, fire hydrants, and sampling stations. Charlotte Water (CLTWater) tests water throughout Mecklenburg County daily.

Your home’s humidity will typically be less than one Nephelometric turbidity unit (NTU). A glass of water with a reading of five NTU is just noticeable to the average person. If you notice cloudy water, it is likely a higher NTU, and you should follow the steps above.