The stormwater fee helps fund the City’s drainage projects, storm sewer maintenance, stormwater program, and new storm sewer construction. The stormwater fee was adopted to provide a perpetual, dedicated source of funding. The chart below shows how the stormwater rates are calculated based on multiples of a standard fee for single family residences. The standard fee rate automatically increases by 3% from the previous year’s fee. The 2024 standard fee for a residential parcel is $6.46.

Stormwater Fee Table

*Non-residential properties that have > 400 sq. ft. and < 4,150 sq. ft.
will be charged a minimum of one ERU.

Non-Residential Example:

Property containing 8,300 square feet would be divided by 4,150 (2 ERUs) and then multiplied by that year’s standard single family residence fee to determine the Non-Residential fee.

Apartment Fee Billings

Apartment complexes are considered non-residential, so the fee for the overall complex will vary based on the non-residential fee calculation. The fee will be added to the main complex utility billing account. Apartment residents should contact their apartment office to determine how this fee will be applied.

Stormwater Rate Study

A Stormwater Rate Study was completed for the City of Carmel in 2013. The study determined that establishing an equivalent residential unit (ERU) rate system was the most fair and equitable method of assessing storm water fees to all property owners.

In an ERU rate system, the impervious surface areas (roofs, driveways, sheds, etc.) of single family residential parcels are sampled throughout the city and an average impervious area is determined. The study found that the average impervious area of a single family residential (SFR) property in Carmel is 4,150 square feet. The impervious area for each non-residential property was then calculated and divided by the ERU square footage to determine how many multiples of the ERU exist on the non-SFR property. The total amount of ERUs in the city was then equated with a monetary value which would meet the projected yearly budgetary needs of the Department.

Non-SFR properties/units will be charged a multiple of that year’s SFR fee per month, based on the square footage of impervious area on the property divided by 4,150 square feet. For example, a property containing 8,300 square feet, would be 2 times the SFR fee (8,300/4,150 = 2). Non-SFR properties containing less than 4,150 square feet will be charged a minimum of 1 ERU.

All unimproved residential properties that contain no impervious areas will be charged 0.33 ERUs.

If you have questions or concerns,
please contact the Department of Stormwater Management at
317-571-2441 or email stormwater@carmel.in.gov.