Quality of Streams


When out on our lakes and streams, be mindful of water conditions. If it has rained in the past 72 hours, it is best to avoid swimming in coves as they are the main area where stormwater empties into the lakes, often carrying sediment and bacteria.

If the water is discolored or has a smell, please report to 311 or download the CLT+ App (Apple App and Google Play Store) or submit an online form to make a report. These conditions could be indicative of stormwater pollution - When In Doubt, Stay Out!

If you would like to receive swim advisory information straight to your phone, simply text MECKNOSWIM to 888-777. You can also sign up for alerts.

Swim Advisories

A Swim Advisory is issued by Charlotte-Mecklenburg Storm Water Services, in conjunction with the Mecklenburg County Health Department, when a natural body of water is considered a public health threat for swimmers. Examples of conditions that may cause an Advisory include a sewage spill, a chemical spill, Harmful Algal Bloom (HAB) or unsafe chemical or biological levels identified during routine monitoring. Once an Advisory is issued, the water is typically tested once a day until it is considered safe for swimming.

Although surface water quality is routinely monitored throughout Charlotte and Mecklenburg County, it is impossible to know, at any given time, whether or not water is safe for swimming. The following precautions(PDF, 125KB) should always be taken when swimming in natural bodies of water. It is also important to know that typically streams in Mecklenburg County are only suitable for minor contact activities such as fishing and kayaking, but not for swimming. Lake Norman, Mountain Island Lake and Lake Wylie are all considered suitable for swimming.

When a Swim Advisory is issued or removed, the media is sent a press release, and information is posted in our Newsroom and on Charlotte-Mecklenburg Storm Water Services' Facebook and Twitter pages. 

If you would like to receive swim advisory information straight to your phone, simply text MECKNOSWIM to 888-777.

Harmful Algal Blooms (HABs) 

Algae are microscopic, plant-like organisms that are the base of the food web in lakes, ponds, and streams. Under the right environmental conditions, algae can rapidly grow and form an algal bloom which may appear as surface scum, water discoloration, or both. Algal blooms that are formed by species that can produce toxins are known as harmful algal blooms (HABs), but can also be referred to as cyanobacteria blooms, blue-green algae blooms, cyanoHABs, or potential HABs. The toxins produced by HABs can cause adverse health effects in humans, pets, and wildlife. Visit our HABs page for more information about safety, identification, reporting, and resources.


You can visit our new story map for an interactive look at the lakes in Mecklenburg County. This map will show you data from all of our lakes, information on how, where, and why we monitor, and how you can enjoy the lake.

The Lake Use-Support Index (LUSI) was developed to communicate vast amounts of surface water quality monitoring data collected from Lake Norman (with Lake Davidson and Lake Cornelius), Mountain Island Lake, and Lake Wylie along the western border of Mecklenburg County. These scores are updated every other month and represent data collected six times a year from 28 monitoring sites. The LUSI is constructed around four categories of surface water quality data that represent the most important pollutants and indicators of environmental health including:

  • Bacteriological (fecal coliform and e. coli)
  • Metals (arsenic, barium, cadmium, chromium, copper, lead, manganese, nickel, selenium, zinc)
  • Nutrients (chlorophyll A, nitrogen, phosphorus, nitrates, nitrites)
  • Physical (temperature, pH, dissolved oxygen)

Scores range from 0-100, with a score of 100 indicating the best surface water quality possible. The LUSI maps also include icons that also show where it is safe for swimming.

Lake Norman:

Mountain Island Lake:

Lake Wylie:

See also the Lake Monitoring Report(PDF, 2MB) for in depth information about lake water quality compared to state standards. Lake Monitoring reports are typically updated every year.

Fish Consumption Advisories 

Fish consumption advisories for Mecklenburg County's lakes are issued by the state and are determined by testing the tissue of the fish. These advisories help people understand if they should limit or completely avoid eating different types of fish. In some cases, advisories are stronger for children or women of child-bearing age. See current fish consumption advisories(PDF, 170KB) affecting Charlotte-Mecklenburg.

No Wake Zones for Lakes in Mecklenburg County 

A No Wake Zone is an area of a lake or river where vessels are required to travel at an idle speed or a slow speed, so no appreciable wake is created. No Wake Zones are typically defined by floating buoys. Only the Marine Commissions and the NC Wildlife Resources Commission can approve a No Wake Zone.

The Lake Norman Marine Commission and the Lake Wylie Marine Commission handle requests for the establishment of No Wake Zones on these respective lakes.

There is no Marine Commission for Mountain Island Lake so the NC Wildlife Resources Commission must approve No Wake Zones for this lake. The NC Wildlife Resources Commission has appointed Mecklenburg County to administer the application process.

Mecklenburg County's process for establishing a No Wake Zone, starting with submittal of an application, can take between one and two years to complete. The process is summarized as follows:

  1. Interested person submits an application for a No Wake Zone on Mountain Island Lake(PDF, 207KB).
  2. Mecklenburg County Board of County Commissioners (BOCC) advertises in a local newspaper the date, time and location of a public hearing on the No Wake Zone proposal.
  3. The BOCC holds a public hearing and votes to approve or deny the proposal.
  4. If approved, the County will submit the necessary paperwork to the Wildlife Resources Commission.
  5. If approved by the Wildlife Resources Commission, the County will install and maintain buoys identifying the No Wake Zone.


The Stream Use Support Index (SUSI) was developed to communicate vast amounts of surface water quality monitoring data that is collected from streams throughout the City of Charlotte and Mecklenburg County. The scores are updated quarterly and represent data collected 12 times a year from 24 monitoring sites. The SUSI, or score, is constructed around five categories of surface water quality data that represent the most important pollutants and indicators of environmental health including each year. This index or score is constructed around five categories of surface water quality data that represent the most important pollutants and indicators of environmental health including:

  • Bacteriological
  • Metals
  • Nutrients
  • Physical
  • Biological

See the following SUSI interactive map to see the surface water quality score for the watershed where you live or for any address you choose! Scores range from 0-100, with a score of 100 indicating the best water quality possible.

Additional information about streams and lakes designated as impaired by the State of N.C., or waterbodies that are on the 303(d) list, please see the "Impairments" section on our Watershed Planning page.

Sanitary Sewer Overflow

Charlotte Water is the City's department that is responsible for the collection and treatment of wastewater (sewage) from households and businesses in Charlotte and Mecklenburg County.  On average, Charlotte Water collects over 30 billion gallons of wastewater annually through over 4,000 miles of pipes which it then treats at five wastewater treatment facilities. With the vast amount of wastewater transported through the large network of pipes, it may come as no surprise that some wastewater escapes the system. The good news is that 99.998% of wastewater is typically treated, but the bad news is that what does escape has negative impacts on streams and lakes. The most common way it escapes is through leaks in the system and sewage overflows. Sewage has high levels of bacteria and other microorganisms that are harmful to public health and aquatic life. Sewage that enters surface waters consumes oxygen in the water which can lead to fish kills.

Sewage overflows happen when substances block the line, causing sewage to back up and come out of manholes. Grease is a common cause of sewer line blockages. Please see Charlotte Water's website for more information about common causes of sewage overflows and what residents can do to help prevent them.

To help locate sewage overflows into streams and lakes, Storm Water Services staff conducts extensive sampling in surface waters for fecal coliform bacteria, an indicator of sewage discharges. If results are above a specific action level, staff continues testing to determine if a sewage leak or overflow is suspected. If one is suspected, they notify Charlotte Water and work collaboratively to determine if the source is from their sewer collection system.

To reduce sewage overflows, Storm Water Services and Charlotte Water also team up to educate multi-family residential communities. Each year, staff targets 100 multi-family complexes with information about requirements to develop an Operation and Maintenance Plan for their private sewer system.  They provide one-on-one assistance to these residential complexes, offer optional workshops, and conduct follow-up inspections to help ensure that the plans are being implemented. Please find more information and guidance documents related to the multi-family residential permits and community education program on Charlotte Water's website.

Soil Erosion & Sediment Control

Sediment is the number one pollutant for surface waters throughout the City of Charlotte and Mecklenburg County.

Sediment is soil particles that have eroded from the land or streams banks. Sedimentation is the process of soil particles depositing and accumulating in areas such as the bottom of a stream, pond, wetland, or lake. Sedimentation results in significant negative impacts such as increased water treatment costs, destruction of wildlife habitat, reduced flood protection, diminished property values, and even negative health impacts.

In urbanized and developed areas, erosion and sedimentation are caused primarily by rainfall and stormwater runoff. When vegetation is removed, soils that are exposed and disturbed at construction sites are transported by wind and rain to streets and stormwater drainage systems, and then into streams, ponds and lakes. Increased stormwater runoff from impervious surfaces causes bank erosion and stream instability, resulting in additional sedimentation impacts. When one considers that hundreds (or even thousands) of acres of land are disturbed and developed across Charlotte and Mecklenburg County every year, the importance of soil erosion and sedimentation control is apparent.

For these reasons, the City of Charlotte, Mecklenburg County and the six towns have soil erosion and sedimentation control regulations. These regulations require that land developers meet mandatory standards for stormwater protection during construction activity that will “permit development of this [Community] to continue with the least detrimental effects from pollution by sedimentation.” (Sec. 17-2 Charlotte Code of Ordinances).

More specifically, these regulations require builders and developers to implement structural Best Management Practices (BMPs) like perimeter sediment fence, construction entrances, and sediment basins to control sedimentation from their site. Larger projects that disturb one or more acres must first seek and obtain plan approval and permit coverage from Charlotte or Mecklenburg County prior to conducting any land disturbing activity to ensure that BMPs are selected properly and implemented correctly.

The City and County each employ a team of professionals to inspect construction sites and monitor receiving streams within their jurisdiction. When inspectors find deficiencies in site operation or management they work with owners and developers to correct those issues and ensure optimal erosion and sedimentation protections. In cases where violations are excessive, intentional, or result in significant offsite sedimentation or environmental damage, civil penalties up to $10,000 for each day the site remains non-compliant can be assessed.

If you observe a suspected violation like muddy streets or the impacts of sedimentation in streams, please report it immediately so City or County staff can respond and take steps to minimize impacts to water quality. You can call 311 or email us to report suspected violations. Visit Report A Problem for more info. You may also contact staff from the City of Charlotte or Mecklenburg County directly. See contact information below.

If you are interested in additional information about Soil Erosion and Sedimentation Control, you may attend a quarterly training seminar. For almost 15 years the City of Charlotte and Mecklenburg County have partnered to offer a training class specifically related to the practice of soil erosion and sedimentation control within these jurisdictions. For more information about the class, including the date of our next class and registration options, see CMCSI Classes.

To view local Soil Erosion and Control Ordinances and learn more about the permitting process, see Regulations.

Questions about Soil Erosion?

Jay Wilson
City of Charlotte Water Quality Program Administrator

Jason Klingler
Mecklenburg County Project Manager I

Stormwater & Pollution of Streams and Lakes


Stormwater is rainwater or snowmelt that isn't absorbed into the ground. Stormwater runs off rooftops, down street curbs, and across parking lots where it enters the storm drains.

Storm drains are often confused with sanitary sewers, but in the City of Charlotte and Mecklenburg County, they are separate systems and very different. Storm drains take rainwater through underground pipes directly into a local stream or lake. Stormwater is not cleaned at a treatment plant.

Sanitary sewers carry sewage from our homes to a wastewater treatment plant to be cleaned before it is released into a stream, river, or lake. Examples of sewage include dirty water from our toilets, showers, kitchens, and laundry machines.

Because stormwater is not cleaned at a treatment plant, the storm drainage system can carry pollution from our yards and streets directly into local streams, rivers, and lakes.

See the Stormwater, Wastewater and Drinking Water graphic(PDF, 15MB) to visualize these three water systems. 

Pollution of Streams and Lakes

Stormwater is the number one pollution problem for our nation's streams and lakes. Rainwater washes off a variety of pollutants from the land into the storm drainage system and into streams, rivers, and lakes.

Nonpoint source pollution is another name for stormwater pollution. Nonpoint source pollution comes from all over the land. Here are some common examples of nonpoint source pollution:

  • Soil from construction sites
  • Oil from cars
  • Fertilizers and pesticides from yards
  • Dog poop from parks and yards
  • Litter from streets

Point source pollution is another problem for our streams and lakes. Point source pollution comes from a single source. Common examples include:

  • Sewage overflows from a sanitary sewer
  • Dumping of wastes from a business or person
  • Illegal discharges
  • Spills from auto accidents

Another problem for streams, rivers, and lakes is the volume of stormwater generated in the urban environment. As a community becomes more urban, there are more impervious surfaces. Impervious surfaces don't allow rain to be absorbed into the ground generating a lot more stormwater. Examples of impervious surfaces include sidewalks, roads, and rooftops.

All that stormwater rushes directly to a stream and acts like a fire hose, eroding stream banks and filling the stream with a lot of sediment or mud. The velocity of stormwater during a storm combined with all the sediment or mud generated makes it difficult for aquatic organisms, like fish, to live.

Consider this example:

one inch of rain on an acre of woods 

produces little to no stormwater runoff. 


one inch of rain on an acre of asphalt 

produces 27,000 gallons of stormwater runoff 

that contains a variety of pollutants 

and causes widespread erosion.

Detention basins and stormwater regulations associated with land development activities help manage volumes of stormwater. Detention basins help slow down stormwater so it can be slowly released to a local stream and pollutants, like sediment, can settle out.

Here are some links to learn more about the quality of our local streams and lakes:

What Can I do to Help Prevent Pollution? 

  • Prevent Pollution. See our Top Tips for preventing pollution.

  • Report Pollution. If you see a discolored stream, or if it smells strange, report it. When in doubt, report it. See Report a Concern to learn about three ways to report pollution.

  • Educate. According to public opinion survey, approximately 50% of City and County residents don't know storm drains lead to streams and lakes. Help inform people that storm drains go directly to streams and lakes.

  • Volunteer. Help teach kids and students about stormwater and environmental stewardship through one of our many volunteer opportunities.

Stormwater Pollution Hotspots

Stormwater pollution hotspots are areas where illicit discharges and stormwater pollution are most likely to occur. Staff determine these hotspots by reviewing stream monitoring data and previous locations of pollution-related incidents and violations, and by locating highest density commercial business corridors where illicit discharges are more likely to occur. These corridors have more restaurants, car repair shops, gas stations and other commercial establishments than other areas. Staff also focus on the identification of hotspots in smaller streams (watersheds that drain less than 50 acres). This is because larger streams (watersheds larger than 50 acres) are surveyed once every five years during stream walks.

Investigation of Stormwater Pollution Hotspots includes more frequent facility inspections, monitoring of streams and stormwater outfalls, and surveying the area for signs of pollution such as staining on paved areas, puddles of discolored water, or poor outdoor storage practices.

Stream & Lake Buffers

Stream and lake buffers are vegetated areas or strips of land adjacent to water bodies such as streams and lakes. They generally contain a mix of trees, bushes, grasses, and other vegetation and provide a variety of benefits related to protecting water quality. Stream and lake buffers are also “no build zones” when local and state buffer regulations apply.

Stream and lake buffers are essential for protecting water quality of streams and lakes and important to our community for the following functions they provide:

  • Protect water quality by filtering pollutants in stormwater runoff;
  • Allow water to soak into the ground and recharge groundwater supplies;
  • Provide storage for floodwaters;
  • Allow channels to meander naturally;
  • Provide suitable habitats for wildlife;
  • Provide shade to reduce water temperatures; and
  • Provide soil stability through root mass.

There are four different types of stream and lake buffers in Charlotte-Mecklenburg as required by various ordinances adopted by the City of Charlotte, Mecklenburg County and the six towns between 1993 and 2008. Ordinance requirements differ significantly based on the buffer type and the jurisdiction where the buffer is located. In all situations where two buffer types apply to the same stream segment, the buffer that is more protective of water quality always applies. The following provides a summary of the four different buffer types in Charlotte-Mecklenburg.

  1. Water Supply Watershed Buffers
  2. Surface Water Improvement & Management (S.W.I.M.) Buffers
  3. Post-Construction Buffers
  4. Goose Creek and Six Mile Creek Buffers

For a summary of the differences between these types of buffers please see Overview of Charlotte-Mecklenburg Stream and Lake Buffer Requirements(PDF, 369KB).

See POLARIS Instructions for Stream and Lake Buffers(PDF, 370KB) to determine if your property has a water quality buffer.

See Determine Stream and Lake Buffer Requirements for a Specific Parcel(PDF, 96KB) for the following information:

  • Requirements for a specific parcel
  • Disturbances allowed and NOT allowed under the law
  • Mitigation of disturbances
  • Violations

For more information about the specific regulations that require stream and lake buffers, see Regulations.

Questions about Stream and Lake Buffers?

Rusty Rozzelle
Mecklenburg County Water Quality Program Manager

Jordan Miller, PE
Surface Water Quality and Environmental Permitting Manager
Charlotte Storm Water Services