How Are Stormwater Fees Determined?

Stormwater Service Fees are determined using an aerial survey completed by Charleston County in 1992 in conjunction with records from the Charleston County Tax Assessor’s Office. 

From the aerial photographs we have measured the impervious surface or improvements such as buildings, parking lots, sidewalks, porches, sheds, decks, swimming pools and other improvements made on your property that effect the amount of stormwater that runs off. 

In order to be more efficient we measured a sample of single family homes and determined the average amount of impervious area on a typically developed residential lot in the City of Charleston. 

The average home contains about 2,200 square feet of impervious surface. The city has defined these 2,200 square feet as an Equivalent Residential Unit (ERU) and all bills are determined in terms of the number of BERU’s which is displayed on your monthly utility bill from the Commissioners of Public Works.

The fee is calculated based on the following criteria:

  1. All single family residential properties are billed one ERU per month.
  2. Multi-family residential properties are billed three-quarters of one ERU for each residential apartment.
  3. Non-residential properties are billed one ERU for each 2,200 square feet of impervious surface. Gravel parking and storage facilities are billed at one-half the rate for each ERU.
  4. Owners of underdeveloped property pay no fee.

Sample calculations below show how the fee for a typical non-residential property is calculated.

  1. Gerlita Glover

    Stormwater Administrative Assistant
    Phone: 843-724-3798

  2. Stormwater Management

    Physical Address
    2 George St
    Suite 2100
    Charleston, SC 29401

    Mailing Address

    Charleston, SC 29402