Stormwater Utility Fee Information

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City of San Marcos

Stormwater Utility Fee Update Fact Sheet 


The City of San Marcos has recently revised its Stormwater Utility fee structure to ensure better equity among customer classes and to conform with established drainage utility fee standards in Texas. The City of San Marcos Stormwater Utility was implemented in 1999 and is the primary funding source for drainage capital improvement projects and for the operation and maintenance of the City’s drainage infrastructure with the purpose of reducing flooding, improving water quality, and maintaining regulatory compliance of the municipal separate stormwater system (MS4).

How is the fee determined?

The fee was determined in the past with a hybrid model. Residential units (detached) were assigned a fee based on parcel land area, commercial uses were assigned a fee based on total amount of impervious area, and multi-family developments were assigned a fee based on the total number of units. The new rate structure moves to a wholly impervious-based system that utilizes a standardized unit of measurement, the equivalent residential unit (ERU), to apportion Stormwater Utility fees equitably among and between the different customer classes. (R1, R2, R3, NR) The following table compares the prior and new Stormwater Utility rate structure.

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Note – The existing and proposed rate structure tables are based on 2020 Stormwater Utility rates.

When will the changes occur?

The new Stormwater Utility rate structure will become effective October 1, 2020.

What fee changes can customers expect?

Many Stormwater Utility customers will experience a monthly fee change with the transition to the new rate structure.  For residential properties, three rate tiers will be assigned based on impervious area instead of land area. Commercial properties will now be classified as non-residential (NR) properties to reflect that this customer class contains all properties that are not residences of 1-4 units. The method for determining the fee for these properties remains the same (impervious area/ ERU* Stormwater Utility rate). The ERU, or equivalent residential unit, has changed from 2,250 square feet to 2,575 square feet which will generally reduce the fee for the non-residential customer class. This new ERU more accurately reflects the average impervious cover for a detached residence within the City of San Marcos and establishes an equitable unit of measurement between these customer classes. For multifamily properties that have five (5) or more units, these properties will be billed to the owner or owner’s representative and placed in the non-residential (NR) customer class.

Have there been any other changes to the Stormwater Utility?

Concurrent with this fee structure change, a recent city-wide impervious determination from 2017/2018 leaf-off aerial photography was performed to update and verify the impervious cover associated with developed property within the City Stormwater Utility service area (San Marcos city limits). As a result, some Stormwater Utility accounts have had their associated impervious area increased or decreased and this can also affect the fee change that customers may experience.

How can I find my new Stormwater Utility fee?

A Stormwater Utility Fee Lookup tool was developed to assist property owners with determining what their new Stormwater Utility fee will be. This tool can be accessed by following the link below. To find an account, enter your address or Parcel ID and information such as parcel impervious cover totals and the new Stormwater Utility fee associated with the parcel will be displayed:

What if I believe my information is not correct or I have additional questions?

If a property owner believes there are errors in the information used to determine the Stormwater Utility fee, the city will work with you to answer any questions or resolve. Contact the City’s Engineering/CIP Department at (512) 393-8130, send an email to