When land is underdeveloped, rain and melting snow will soak into the land or naturally flow to streams and rivers. When land is developed an impervious surface is created. An impervious surface is a man-made area that will not readily absorb water as it falls.

Examples of impervious surfaces include paved areas, roof tops, streets and sidewalks. Developed land cannot absorb the water as easily and many flow patterns are changed. In order to control the storm water, storm drainage facilities have had to be built. These facilities must be operated, maintained, renewed and replaced in order to provide a safe flow of storm water.

To control storm waters and receive the benefits of that control, there is a cost. Since everyone in the city benefits, the Denver City Council passed an ordinance which authorizes a storm drainage service charge to be collected from the owners of all improved parcels of land.

How is my storm drainage bill calculated?

The annual charge to a property owner is based on the relative impact the property will have on the storm drainage system.

For instance, a parking lot will have more storm runoff than a grassy area of the same size. The charge is based on the ratio of impervious surface area to total parcel area. Based upon that ratio, a rate is applied to the impervious area to calculate the annual charge. The higher the ratio, the greater the rate.

Why is my sanitary sewer bill combined with my water bill?

To reduce costs and as a convenience to customers, a combination bill was developed. The sanitary sewer bill is based on the water consumption metered by the Denver Water Department. This information is included on your combined bill.

How is my sanitary sewer bill calculated?

Every residential customer has a two-month winter billing period. Metered water consumption for this winter period established sanitary sewer charges for the entire year. Even though your water use may increase during the summer, your sanitary sewer charges will remain constant.

The sanitary sewer charge for commercial property is based upon actual metered consumption in each billing period during the year.

Who do I contact when I have questions about my storm drainage or sanitary sewer bill?

You may phone Wastewater's Customer Service Unit at 303-446-3500. Our telephone hours are 7:30 a.m. to 3:30 p.m., Monday - Friday. Our offices are open to answer your questions from 7:30 a.m. to 4:00 p.m., Monday - Friday. We are located at 2000 West 3rd Avenue.