Surface Water Quality

​​Quality of Streams & Lakes​

​​Information about the quality of local streams and lakes is organized as follows. Please scroll down for more information about these topics.

  • Streams​
  • Lakes
  • Swimming advisories
  • Fish consumption advisories


Streams

​​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 of 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​. ​

Lakes

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: Highly Supporting – all sites as of November 30, 2016 
         See the LUSI map for Lake Norman 
            A fish consumption advisory is in effect

    • Mountain Island Lake: Partially Supporting to Highly Supporting as of November 30, 2016 
         See the LUSI map for Mountain Island Lake 
            Fish consumption advisories are in effect for more than one species

    • Lake Wylie: Partially Supporting to Highly Supporting as of November 30, 2016      
        See the LUSI map for Lake Wylie ​
            Fish consumption advisories are in effect for more than one species

See also the 2014 Lake Monitoring Report​ for in depth information about lake water quality compared to state standards.  Lake Monitoring reports are typically updated every year.

​​​Swimming Advisories
A Swimming 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, 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 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 Swimming Advisory is issued or removed, the media is sent a press release, and information is posted below and on Charlotte-Mecklenburg Storm Water Services' Facebook and Twitter pages.

Swimming Advisories - current news​ 

There are no swim advisories in effect for Mecklenburg County area waters.​​​​​​​

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​ affecting Charlotte-Mecklenburg.