Post-Construction Stormwater Ordinances

Post-Construction Stormwater Ordinances (PCSOs) of the City of Charlotte, Mecklenburg County and the six towns protect streams and lakes from water quality and water quantity problems generated by land development and impervious surfaces.

Consider this example that demonstrates the impacts of land development and new impervious surfaces:

one inch of rain on an acre of woods
produces little to no stormwater runoff.
vs
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.

PCSOs ensure that new developments are designed to minimize impacts to water quality and that structural Best Management Practices (also called Stormwater Control Measures) are built and then maintained after development is complete.

In 2004 and 2005, a stakeholder committee developed the first PCSO for the region using extensive scientific data and cost analysis information. While the City, County and six towns tailored this PCSO for their respective communities, they all have a similar base and intention that was developed as part of this stakeholder process. They all incorporated a division of the Charlotte-Mecklenburg region into watershed districts. These watershed districts are based on environmental priorities that warrant greater protection in specific areas. They also incorporate three main requirements for new developments:

1. Best Management Practices (BMPs) or Stormwater Control Measures (SCMs) to reduce total suspended solids, phosphorous, flooding and erosion.
2. Stream and Lake Buffers (natural vegetation along streams and lakes) ranging in width from 30 to 200 feet.
3. Open Space requirements that vary from 10 to 25 percent of the developed area, depending on the amount of Built-Upon-Area (BUA).

Examples of ways the County and six towns have customized the PCSO include:

• Huntersville’s PCSO has a Low Impact Development requirement to protect Mountain Island Lake where a drinking water intake is located.
• Mint Hill’s PCSO requires infiltration practices in the Goose Creek Watershed to protect an endangered freshwater mussel.
• Mecklenburg County requires larger buffers and lower development densities in areas that drain directly to lakes used for drinking water.
• Mecklenburg County and the six towns provide different mitigation options and have different requirements for steam and lake buffers.

Examples of ways the city has customized the PCSO include:

• The city applies the PCSO to redevelopment as well as development. This broader application helps restore waterways in developed areas where they may already be impaired.
• The city allows qualifying developments to pay a mitigation fee in lieu of implementing PCSO controls on-site. Mitigation fees are used in the watershed where they are collected to fund the implementation of projects that remove pollutants at faster rates than would’ve been achieved on-site.

For copies of the current PCSOs of the City of Charlotte, Mecklenburg County and the six towns please visit Stormwater Regulations. This is also where you will find associated Administrative Manuals, Design Manuals, policies, forms, and resources to help land development activities comply with applicable PCSOs.