The stormwater system is separate from the sanitary sewer system. Runoff from rain, snowmelt, excess lawn watering and similar activities is transported via the stormwater system to our waterways. This system and our storm drainage facilities require continuous operation, maintenance, renewal and replacement to try to prevent runoff, which can flood streets and damage property.
There isn’t a treatment facility for stormwater like there is for the wastewater from the sanitary sewer system. But the City and County of Denver does maintain many sustainable stormwater management facilities such as grassy swales and retention ponds that help remove some impurities before the water is discharged to major waterways. The City is also researching potential stormwater treatment options to ensure future environmental standards are met.
Developed properties have impervious surfaces (buildings, sidewalks, parking lots, etc.) that prevent water from permeating into the ground. Thus, all developed properties have an impact on the storm drainage system. Therefore, in 1981, Denver City Council determined that each and every owner of a lot or parcel of developed property within the city should pay for the availability, use, and maintenance of our storm drainage system. As stated in the Denver Revised Municipal Code (DRMC) 56-112, the Storm drainage fee shall be calculated by determining the ratio of impervious surface measurements to parcel or lot size. This calculation is applied in the same manner whether the property is residential, commercial or industrial.
The DRMC does not allow for the fee to be based upon the quantity of storm water runoff that actually enters into the city’s drainage system. Such a method would be too expensive and cumbersome to implement and maintain.
To ensure that everyone is billed equitably, we try to keep pace with the construction changes throughout the city and update our impervious area measurements accordingly. To meet this goal, inspections are performed on properties throughout the City and County of Denver. These inspections are done using aerial photographs and GIS, site plans for new construction, and site inspections when deemed necessary. An inspection will update an account, and based on the data, may result in changes to the annual charge. Customers are encouraged to contact our office at 303-446-3500 if there are any questions regarding their account and how the charge was determined.
If you think the impervious surface measurements for your property are incorrect, please call us at 303-446-3500. We will be glad to explain the measurements and resulting storm drainage fees or changes between prior charges and current charges. If after this conversation you are sure the measurements are incorrect, please write us or submit the PDF form linked on this page to initiate an impervious surface re-measurement.
Pay your annual storm drainage charge: Although it is still calculated annually, the fee will be divided into two bills sent to you six months apart. You may pay each semi-annual bill in one, two, or three installments.
Due dates and the dollar amounts due are posted on your bill. Since this is now a semi-annual bill, the second half of your annual storm charges will be billed to you six months after you received the first. Again, you will have the option of paying in full or in installments for the second semi-annual bill.