Thornton Taxes Explained

The City of Thornton levies a sales tax on tangible personal property or taxable services which are purchased, sold, leased or rented in the City. The term "in the City" includes any personal property or taxable service that is provided or delivered to the purchaser within City limits. Sales tax is a transaction tax that is collected and remitted by a retailer. Retailers collect a total of 8.5% for sales made in Thornton. The City portion (3.75%) must be remitted directly to Thornton. The remainder of the taxes (4.75%) are remitted directly to the State of Colorado. For businesses located at the Denver Premium Outlets center, please see below.  View a map of Thornton's boundaries: Boundary Map [PDF/0.9MB]

The total combined sales tax rate in Thornton is 8.5%, and is comprised of the following taxes:

City of Thornton                          3.75%
State of Colorado                        2.90% 
RTD/CD                                       1.10% 
Adams County                             0.75% 
Total                                           8.50% 

Marijuana Products
The City of Thornton charges an additional 5% sales tax on all marijuana products sold in the City, making the total City sales tax rate 8.75% on all marijuana products.  Additional state collected taxes will also be collected at the time of sale.

Denver Premium Outlets
The City tax rate for businesses located in the Denver Premium Outlets shopping center is 2.35%.  This rate is in addition to Public Improvement Fees (PIF) that the developer may require their tenants to collect on sales transactions to finance a portion of the cost for the public improvements surrounding this area.  Generally, these improvements are financed through a Special District, and the PIF collected repays the PIF debt incurred by the developers.

Effective January 1, 2025, the PIF at the Denver Premium Outlets center is 2.40%.  The PIF is NOT a tax and is NOT remitted to the City.  Instead, the PIF is a fee that becomes a part of the total cost of the sale/service, and it is subject to sales tax.  The PIF is collected on all taxable sales/services made within the outlet center and is remitted to the Village at Dry Creek Metro District.

Taxable Items
Some examples of items subject to Thornton's sales and use tax are as follows:

• Automobiles
• Computer software
• Cable television
• Linen services
• Maintenance contracts
• Restaurant food
• Tangible personal property
• Food for home consumption (groceries)
• Gas and electric service
• Telecommunication services 
• Cover/door/admission charges 
• Recreation services 
• Automated or hand held car wash 
• Construction equipment

Use tax is a complement to sales tax. If City sales tax has not been charged on a taxable item or service, then use tax is due. The purchaser is responsible for reporting use tax. Use tax should be reported on line 10 of the City Sales and Use Tax Return. Download and print form: Tax Return 

Sometimes another city's tax is paid on items brought into Thornton. If that city's tax is less than Thornton's, then the difference between the two rates is due as use tax. Some examples of use taxable transactions follow.

Use Tax Examples

Example #1 - ABC Company purchases a computer from a store located outside of Thornton. The store charged 7.0% sales tax (4.0% State + RTD and 3.0% city tax). ABC Company brings the computer back to Thornton to use in the business.

The difference in the store's city rate and Thornton's is 0.75% (3.75% - 3.0%).  ABC Company owes use tax to the City of Thornton at a rate of 0.75%.

Example #2 - XYZ Manufacturing ordered a computer over the internet. XYZ received the computer and invoice; there was no sales tax on the invoice.

XYZ has not paid any city sales tax on this computer and owes use tax to Thornton at a rate of 3.75%.

Example #3 – ABC Company's corporate headquarters are in Texas. ABC Company ordered a new computer. The Computer was delivered to corporate headquarters in Texas, and later shipped to their Thornton location. A review of the invoice shows Texas sales tax of 8.75% was charged.

Sales tax equal to or greater than Thornton's rate has already been paid. No use tax is due on this transaction.

Lodging Tax
The City of Thornton levies a lodging tax on the price paid or charged for the lease, rental or furnishing of rooms or other public accommodations. The lodging tax rate is 7.0% and is levied in lieu of sales tax. Customers who enter into a written agreement for occupancy of a room or public accommodation for a period of thirty or more consecutive days are exempt from this tax.

Telephone Tax
The City of Thornton levies a telephone tax on any business providing local exchange telephone service to inhabitants of the City. The amount of the tax is $8.00 per local telephone account per year. The tax is due and payable in four quarterly installments. Each installment is due 30 days after each quarterly period.

E-911 Surcharge
Effective February 1, 2025, the City of Thornton E-911 Authority levies a $2.12 surcharge per month on each telephone line. The surge is collected from Thornton residents and businesses on their monthly telecommunication bill. The surcharge is used to pay for a portion of equipment, personnel, technology maintenance, and other authorized costs pursuant to State statute for the City to provide emergency response service.

Contractors working in the City are subject to use tax on the materials and equipment used to complete the work. For many construction projects, a contractor is required to pull a permit. Use tax is collected at the time the permit is issued. The use tax collected is based on the project's estimated value as follows:

Estimated value * 50% * 3.75%

Contractors doing work under a permit should provide a copy of their permit to materials vendors as proof the City tax was prepaid.

Because the tax paid on the permit is based on an estimate, there may be a refund or additional tax due when the project is complete. Contractors may complete a Project Cost Reconciliation Form providing a complete accounting of all costs including materials and rentals used by subcontractors. ​

For additional information about building specifications and permit requirements contact the Building Department at 303-538-7250.

​Construction Equipment​​

Contractors that store or use construction equipment in the City are required to file an Equipment Declaration Form. The form is required for all leased or rented equipment and any purchased equipment with an original price of at least $2500.

The Form along with proof of any sales tax paid on the equipment must be filed for each project completed in the City.​ 

• Project Cost Reconciliation [PDF/393KB]
• Equipment Declaration [PDF/48KB]

Save Time: File and Pay Online!

To file your sales and use tax return online visit the following website:

​​​www.salestaxonline.com

You may also mail a copy of your return with payment for processing. Note: our mailing address has changed, please mail your returns to:

• City of Thornton, PO Box 209434, Dallas, TX 75320-9434

Note: The City accepts payment by both ACH Debit and ACH Credit if you file online. If you have any questions, please contact the Sales Tax Division at 303-538-7400.

2025 Quarterly Bag Fee Returns now available below. Please complete and mail within 20 days following each calendar quarter to:

• 9500 Civic Center Drive, Thornton, CO 80229. 

Forms

• Sales & Use Tax Return [PDF/76KB]
• Lodging Tax Return [PDF/123KB]
• E-911 Return [PDF/72KB]
• Telephone Tax Return [PDF/78KB]
• Pawnbroker Surcharge Return [PDF/138KB]
• DPO Tax Return [PDF/165KB]
• Marijuana Tax Return [PDF/241KB]
• Claim For Refund [PDF/41KB]
• Bag Fee Return [PDF/128KB]