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.
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.
Mountain Island Lake:
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:
- Interested person submits an application for a No Wake Zone on Mountain Island Lake(PDF, 207KB).
- 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.
- The BOCC holds a public hearing and votes to approve or deny the proposal.
- If approved, the County will submit the necessary paperwork to the Wildlife Resources Commission.
- 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:
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.