Why is it important to manage stormwater?
Thornton is required through its municipal separate storm sewer system (MS4) permit to
manage its stormwater. This effort ultimately results in reduced flood risks that may impact
public safety and loss or damage of property; and preventing untreated stormwater from
flowing directly into rivers and streams.
What is the stormwater utility?
The stormwater utility is an independent funding mechanism to pay for the cost of services
related to the implementation of the stormwater management program, much like the water
and wastewater utilities currently operated by Thornton.
How much is the Stormwater Utility Fee?
- The fee is $5 per month for residential single family detached homes and includes
condominiums, townhomes, duplexes, and manufactured homes. - The fee for non-residential lots (including apartments) is $5 per month per 2,900 square
feet of measured impervious area. The 2,900 square feet is based on the median single-family detached impervious area.
Why do we need a fee to pay for stormwater?
Thornton has grown substantially since its incorporation in 1956, and especially over the past 20 years. With that growth has come a significant amount of impervious surfaces that has greatly increased the amount of stormwater runoff draining to our local rivers, creeks, and streams. The City, through its stormwater program, is legally required to comply with our federal and state-mandated Municipal Separate Storm Sewer System (MS4) permit.
The stormwater program includes ongoing maintenance activities on drainageways, detention facilities, and storm inlets, as well as implementing Capital Improvement Projects (CIP) to address areas at high risk of flooding, and to remove existing structures from the floodplain. By creating a dedicated stormwater funding source through a fee on residential and commercial utility bills, the city is assured of sustainable funding to meet its legal and contractual obligations without depleting the City’s general fund. This will allow other public needs to be better met.
No runoff from stormwater drains off my property, why do I have to pay?
Soils act similar to a sponge. Soils, like a sponge, can only absorb a certain amount of water during a rain event. Once the soil (or sponge) is full the rest leaves as run-off. The benefits of the stormwater utility are realized by all property owners within the service area. CIP projects and ongoing maintenance funded by the Stormwater Utility will benefit everyone by reducing flood impacts to properties, roadways, and other public infrastructure.
How does the stormwater utility fee differ from the fee I pay to the Mile High Flood
District?
Mile High Flood District (MHFD) charges a mill levy tax on all property in the District, which covers up to 50 percent of the cost of large regional and multi-jurisdictional capital and master planning projects across the Denver metropolitan area. MHFD funds also cover up to 100 percent of major maintenance projects, and floodplain mapping studies. This differs from the localized CIP and maintenance projects that
Thornton performs. Thornton’s stormwater utility fee will be used to fund the city’s share of the MHFD projects that are not 100 percent funded by the District.
What is an impervious area?
Impervious areas are surfaces where water cannot infiltrate freely. Examples of impervious surfaces include, but are not limited to asphalt or concrete and fully enclosed man-made structures. A property’s impervious area is the most significant factor affecting both stormwater quality and quantity.
What services are provided?
- Stormwater Program administration to comply with the City's MS4 permit.
- Storm sewer system operations and maintenance including maintaining drainageways, roadway culverts, and cleaning storm pipes and inlets.
- Capital improvement program which involves the design and construction of major CIP projects to reduce flooding impacts in high-risk areas and remove properties from the floodplain.
- Engineering for Master Drainage Plans, typically performed in conjunction with MHFD
- Utility billing and customer service
Who is required to pay the stormwater utility fee?
All property owners within City limits are required to pay this fee. This includes non-profit entities such as churches, private schools and institutions, as well as properties owned by the City, school districts, Adams County, the State of Colorado, and the federal government.
What is the difference between stormwater drainage and wastewater collection? Don’t
they all drain into the same system which we already pay for?
Before the 1970's, many cities built one system that conveyed both stormwater and wastewater, environmental regulations adopted after 1972 required the separation of these combined systems. Combined sewer systems are often incapable of conveying and treating the volume of water from large rain events and the untreated excess flows overflow to streams and rivers. Building the infrastructure to capture and treat combined flows, or to separate them out, is extremely expensive. Fortunately, Thornton has always operated and maintained distinct systems for stormwater drainage and wastewater collection.
How do I pay online?
The Utility Billing Department has several how-to guides.
