Category Archives: Repairs and Spills

Construction, Repairs and Spills, Water Quality

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.

Construction, Repairs and Spills

How Charlotte Water Repairs Water Pipe Leaks

With more than 4,500 miles of drinking water pipe, there is always something to fix. Customers can help by calling 311 or 704-336-7600 when they see or suspect a water leak or water main break. Even after the 311 Call Center is closed customers can say or select ‘water emergency’ to reach our dispatchers 24/7.

Charlotte Water prioritizes leaks so that crews repair emergency leaks first.

The Numbers
• 2,000+ repairs per year. Most are service line repairs (between the water main and meter box).
• There are multiple pipes under major roads (serving immediate areas and zip codes).
• Less than 10% of water pipe infrastructure is over 50 years due to proactive pipe replacement efforts.

Water Pipe Repair Step-By-Step

CLTWater Field Technician installing a flag to mark the leak location.

Investigate

Within hours, a field technician investigates and attempts to repair if it is an easy fix. If it is a leak that requires a construction crew, the technician prioritizes the leak based on severity. Many repairs require coordination with other departments or towns to minimize the impact on customers or drivers.

Staff spray painting where underground utilities are located before digging begins.

Locate

Call NC811 to have other utilities spray paint where their pipes / cables are before digging begins. This can take hours.







Staff turning water off to the leaking water pipe to maintain water to other portions of the neighborhood.

Isolate

Crews turn valves to stop water flowing through the leaking pipe. Crews may attempt to repair the pipe while keeping water in service for customers. Cones and barriers are set up to protect workers.

Excavate

Crews will uncover the pipe to make repairs or replace a section of the pipe. Crews will hand-dig portions to reduce the chance of damaging underground infrastructure.

Restore Water Service

Fire hydrants flow to test water quality before restoring water service to customers.









picture of a crew tamping soil before a compaction test during the phase to rebuild a road after a water leak underground.

Repave and Reopen

Crews will backfill soil into the trench, test compaction, and then repave the road. Repaving depends on the weather. Air temperature is required to be a minimum of 40 degrees and rising in order to properly install asphalt.

Restoration

Straw is placed over dirt if the repair is in a yard. A separate crew or contractor will return several days or weeks later to complete restoration efforts.


What other factors may extend the time between reporting a water leak and the repair?

Crews attempt to repair leaks without a water outage when possible and if there is time will work on solutions to minimize the outage.

Challenges underground

  • Other utilities (fiber, storm water pipes) conflict with the repair and need to be replaced or moved including a large excavation area.
  • Pipe requires full replacement including cutting it out and inserting a new pipe.
  • Repaving depends on the weather. Air temperature is required to be a minimum of 40 degrees and rising in order to properly install asphalt.


Reducing impact on customers

  • Coordinating with Charlotte Department of Transportation, North Carolina Department of Transportation, and/or towns to plan the repair to minimize detours during high traffic times.
  • Installing new valves to minimize the number of customers affected by a water outage.
  • Above ground water pipes may be installed to serve customers if the pipe replacement will take several days to complete.

What caused the water main break / leak?

Unfortunately, since water main breaks occur underground, in most cases we can only speculate as to how exactly the pipe broke. Here are some factors:

  • Construction crews hitting mains while digging for other projects.
  •  Call 811 before you dig to locate the pipes
  • Temperature changes that can cause the soil to expand and contract, putting stress on pipes.
  • Sudden change in water pressure. Quick use of a hydrant to fight a fire or a water main break nearby can cause other pipes to leak.
  • Weak seals or a weakness where two pipes are joined together.
  • Soil conditions (movement, corrosion, extra soil on top pushing down on pipes)

What causes a water main to break?

There are several factors that can cause a pipe to break, including change in temperature, age and external damage.

Who should I call if I see a leak?

If you see or suspect a leak, call 3-1-1 or 704-336-7600 so that Charlotte Water can quickly dispatch a crew to the location. Our dispatchers are working 24/7 so even after CharMeck 311 is closed you can say or select water emergency after the audio greeting to reach our staff.

Learn more at

“Every day, Charlotte Water routinely repairs and maintains water and sewer pipes across our entire service area,” says Charlotte Water Director Angela Charles. “It’s important that we are doing all that we can to keep customers’ trust in our ability to provide clean, safe and reliable water service to the Charlotte region.”

To stay up to date on the most recent events and announcements, follow Charlotte Water on Twitter @CLTWater. For more information on other pipe replacement and restoration projects, visit us at CharlotteWater.org.

Construction, Repairs and Spills

Central Avenue Repair Update

Last month on February 7, Crews responded to a wastewater overflow and found a leaking water pipe under the railroad crossing on Central Avenue. Below is an overview of key steps required to complete the work and reopen the road.

Completed steps

•            Stopped a wastewater overflow and found a leaking water main that contributed to the overflow and was not showing above ground.

•            Installed a water valve to maintain service to customers.

•            Turned off leaking portion of the water pipe.

•            Inspected drinking water, wastewater pipes and storm drains to identify all necessary repairs.

•            Installed another valve for pipe installation process.

•            Installed new water pipes to maintain service long-term.

•            Disconnect the leaking pipe from the water system.

•            Excavate and replace an old brick manhole with a new precast concrete manhole.

Ongoing Steps

•            Add a new lining in wastewater pipes under railroad easement at a future date.

•            Excavate and repair storm drain pipes under railroad crossing. Additional work required at a later date.

•            Rebuild and reopen the road.

All of this while maintaining railroad for daily use by CSX. These repairs require extensive coordination with CSX and Charlotte Department of Transportation (CDOT). The goal is to maintain water service and access to businesses during the repair effort. Local traffic can drive around signs to access open businesses. Crews estimate completing the work around March 17th.

Construction, Repairs and Spills

How Does CLTWater Respond To A Wastewater Overflow?

There is a wastewater spill. What should I do?

Call 311 or 704-336-7600 and say or select ‘wastewater emergency’ to speak to a CLTWater dispatcher. We will respond 24 hours a day.

Photo showing a wastewater manhole in Freedom Park
Wastewater manholes are throughout our neighborhoods. If you see water overflowing, call 311 or 704-336-7600 and select wastewater emergency.

How can I help reduce overflows? 

  • Toss in the trash: paper towels, wipes, hair, cotton swabs, feminine products, dental floss, coffee grounds, and excess food. 
  • Toss in the toilet: only toilet paper. 
  • Drain in the sink: soap suds, small amounts of food from the plate, and liquids. 
  • Always call 811 before you dig.

Take to a full-service recycling center: used and expired oils and grease. 

What causes wastewater overflows?

  • Clogs of wipes, paper towels, leftover kitchen grease, oils, or anything other than toilet paper.
  • Pipe failure (tree falls and breaks pipe, stream/creek erosion causing the pipe to fall into the creek)
  • Tree roots attacking and clogging the pipe
  • Damage by nearby construction. 

How does CLTWater respond?

A rapid response crew will investigate the area and attempt to remove the clog. This work does not impact drinking water quality. Residents and their pets were encouraged to avoid contact with the creek during an overflow response.

How does CLTWater respond to a large overflow?

For example – a tree falls into the creek washing out the creek bank and undermining the wastewater pipe just behind the creek bank. Crews frequently inspect these areas, but erosion can occur quickly during heavy rain events. Crews will:

  • Create a temporary access road or path if necessary to respond.
  • Install a temporary wastewater pipe to bypass the broken pipe and stop the overflow. The pumps and temporary above-ground pipes are checked several times daily to prevent possible wastewater overflows.
  • Stabilize the creek bank.
  • Construct a barrier / temporary stream bank to protect workers.
  • Remove the broken pipe. 
  • Install the new pipe and test it.
  • Rebuild the stream bank with clean fill material (soil). 
  • Remove temporary pipes and pumps.
  • Remove large spoil piles of dirt.
  • Complete grading/drainage.
  • Plant trees/shrubs and seed/straw the area.
  • Restore the stream bank and revegetate.
  • If the greenway was closed during work, it would be restored and reopened. When greenways are affected, CLTWater works with Mecklenburg County on restoration.

How does CLTWater handle tropical storms or heavy rains and prevent spills?

The underground sanitary sewer pipe network is not designed to handle rain, yet the runoff and flooding from large rains inevitably infiltrate the wastewater pipe network. Overflow basins at the five largest wastewater treatment plants capture and later treat more than 160 million gallons of rainwater mixed with wastewater. These equalization basins (EQ basins) help prevent wastewater from overflowing out of manholes in our community.

CLTWater has also added several large wastewater pipes to help reduce the impact of heavy rains. Crews work to prevent rainwater from getting into the sanitary sewer system and are out investigating our system soon after a storm ends.

picture showing excavator beside a creek bank.
Crews create a temporary creek bank to stop the spill. Crews then install pumps to redirect the community’s wastewater around the broken pipe. Crews then add new pipe and rebuild the creek bank.