Filing Returns

Every business is required to file returns on a monthly, quarterly, or annual basis. Beginning in 2012, the city will no longer supply pre-printed return forms. Sales and use tax returns, including zero liability returns, may be filed and paid online using the city's F.A.S.T. Filing system, currently there is no fee to file and pay online.  Returns in variety of formats are also available on the Forms page. PLEASE NOTE THAT RETURNS MUST BE COMPLETED AND RETURNED TO THE CITY EVEN IF YOUR TAX LIABILITY IS ZERO. A minimum penalty charge of $15.00 is applied to all late returns. Timely filing is evidenced by receipt or postmark on or before the due date. For proper credit, ensure that each return includes the applicable period covered, the correct due date, the correct Westminster account number, and the legal name and address of the taxpayer. 

Returns are due on or before the 20th day of the month following the end of a reporting period. If the due date falls on a Saturday, Sunday, or legal holiday, the due date is extended to the next business day (see below). List the reporting period and due date on all returns. Mailed returns must be postmarked by the due date and mailed to:

City of Westminster
Sales Tax Division
P.O. Box 17107
Denver, CO 80217-7107

Please do not staple checks or other attachments to the return. This address is for Westminster tax payments only. Other payments to the city should not be sent to this address.

Tax Return Instructions

Sales & Use Tax Return Instructions
Accommodations Tax Return Instructions
Admissions Tax Return Instructions

Blank returns are available on the Westminster Tax Forms page.

ACH Credit Payments

The City of Westminster is pleased to offer ACH Credit as a payment option for most tax return types. This method allows taxpayers to initiate a credit to the city's bank account via the Automated Clearing House (ACH) system. The payment related data transmitted by the taxpayer allows the city to automatically match the payment with the return mailed by the taxpayer.

Westminster's ACH Credit program has requirements similar to most state tax departments. Taxpayers interested in utilizing this method should review Tax Compliance Guide topic 374. This publication contains important instructions regarding the content and format of the ACH payment file, including the proper format of the required addenda record.

Enrollment is easy. Simply complete an ACH Credit Payment Authorization form, and return it to the Sales Tax Division via mail, fax, or e-mail. Upon approval, a letter containing the city's banking information will be mailed to the ACH contact.

Other Electronic Payment Options

Not all taxpayers will be able to initiate ACH Credit payments with the required addenda records. Taxpayers unable to pay by this method can file and pay sales and use tax returns electronically using the city's F.A.S.T. Filing system. Payment is made by ACH Debit (a withdrawal initiated by the city after the due date). Advance registration is not required to utilize F.A.S.T. Filing.

Is your return complete?

In order to be on time, all taxes due must be correctly reported and paid by the due date. Avoid penalties and interest by checking for the following.

  • The return shows the applicable reporting period covered.
  • The return shows the correct due date (see below).
  • The return shows your 7-digit Westminster tax account number.
  • The return shows your legal name.
  • The return shows your current mailing address. Complete Schedule A if this information has changed since your last filing.
  • All required lines have been completed even if the amount shown is $0.00.
  • The return is signed.

Standard Due Dates

Period Covered  

Due Dates


Due Dates


Due Dates

Monthly Filing            








































































Quarterly Filing            
January - March  






April - June  






July - September  






October - December  






Annual Filing            
January - December