There are two steps in calculating the stormwater fee for a commercial property:

Step 1: Determine the number of Equivalent Residential Units


  • ERU: Equivalent Residential Unit
  • SFCustomer: Square footage of customer’s property
  • SFERU: Size of a typical single-family residential property in Titusville; approximately 0.25 acres or 11,000 square feet
  • IDFCustomer: (0.95 multiplied by the impervious area) + (0.10 times the pervious area). Approximately 95% of the rain that falls on the impervious areas of your property (hard surfaces such as driveways and rooftops) will become stormwater runoff and 10% of rain that falls on the pervious areas of your property (grassed or landscaped areas) will become stormwater runoff
  • IDFERU: 0.30. Approximately 30% of the rain that falls on typical single family residential property becomes stormwater runoff

Step 1 Formula

Number of ERU’s is equal to: (SFCustomer divided by SFERU) multiplied by (IDFCustomer divided by IDFERU).

Step 2. Multiply the Number of ERU’s by the Annual Charge Per ERU

Fiscal Year 2019 Stormwater Fee is equal to: (Number of ERU’s) times ($89.89 per ERU).