Fee Calculations Explained
These calculations are meant to give property owners a general understanding of an equitable rate structure and their approximate contribution based on the formula below. Ideally, these calculations should be done using a property's impervious surface area instead of parcel size. However, that data is not currently tracked by the City of New Orleans.
Formula*:[(Parcel Size x 0.75)/1850)] x 50 = Monthly Fee x 12 = Yearly Fee
Data shows that the average amount of impervious surface area on urban commercial properties is approximately 75% and the average residential property size in New Orleans is 1,850 square feet.**
Equivalent Residential Unit (ERU): A standardized unit of measurement implemented by many stormwater utilities to equate non-residential or multi-family residential properties to a specific number of single-family residences. In our model, one ERU = $50.
Impervious Surface Area: Areas that are not permeable, meaning water cannot pass through them and into the soil. When rainfall hits impervious surfaces, it is unable to infiltrate into the ground and instead flows across the surface as runoff. This runoff can carry pollutants and sediment with it, contributing to stormwater runoff problems. Common examples include paved roads, parking lots, roofs, sidewalks, driveways, patios, and even compacted soils like those found on sports fields.
* Parcel Size multiplied by the Average Impervious Surface Area, divided by the Average Single-Family Residential Home Size, multiplied by $50 = Monthly Fee / Monthly Fee multiplied by 12 = Annual Fee
** Sources cited in our 2025 Water Justice Fund Addendum
