DOR Taxation web site

Prior Enhancements

What taxes or fees were added to the system and when?

Spring/Summer/Fall 2012
The Department of Revenue in the fifth and final phase of conversion involved more public-facing services.

  • Revenue Online,
  • Integrating Electronic Funds Transfer (EFT) into Revenue Online
  • Cigarette and tobacco taxes
  • Alcohol and fermented beverage taxes
  • Gaming tax
  • Pari-mutuel racing fees
  • Food service licenses

    Accounting components for other types of fees, including
    • Driver/Vehicle Services
    • Liquor
    • Gaming
    • Auto Industry
    • Racing
    • Medical Marijuana
    • County vehicle titles and registrations


During 2011, online access for taxpayers to manage their individual income tax accounts and business tax accounts, along with filing and paying online is available through Revenue Online.


August 29, 2011, the Department of Revenue successfully implemented the fourth phase of its accounting system, known within the department as the Colorado Integrated Tax Architecture or CITA. This included converting the following to the accounting system:


  • International Fuel Tax Agreement (IFTA) registration, accounts and returns
  • Exempt fuel refund applications and claims
  • Lodging, Marketing and Short-Term Rental sales taxes
  • Vehicle Daily Rental Fee
  • Waste Tire Recycling Fee
  • Gaming Withholding

Business taxpayers could begin accessing their account information through Revenue Online and could use the following services:

  • Corporation, fiduciary and partnership income tax returns may be filed online, free of charge, just like individual income tax NetFile and these returns may also be amended online
  • Submit E-Filer attachments online rather than mailing them in
  • E-Filing of sales, consumer use, retailer's use, wage withholding taxes and International Fuel Tax Agreement taxes
  • Online payment of all the above taxes
  • Wage withholding annual reconciliation for employers, banking institutions and other entities, replacing the WHO System
  • Special event sales tax forms online
  • Exempt fuel refunds online

April 25, 2011 -- Individual income taxpayer access to accounts, refund status, payment history, make payments, request a payment plan, along with the ability to do the following online: amend individual income tax returns; view and print copies of returns; make an address change; submit a Power of Attorney; and file a protest. Colorado NetFile (a free filing service) for individuals is available through Revenue Online and individual returns may be amended online.


In October 2010, the department sucessfully implemented the third phase of its accounting system. The third phase involved converting sales, use and wage withholding taxes to the new system. The improved system allows us to process taxes more efficiently and assist businesses better. But with the improvements came some changes.


  • Tax Account Numbers are eight digits. Colorado tax account numbers for sales, use and wage withholding had previously been seven digits in length with an “L” or “M” preceding the seven digits. When a business has more than one location, the number had an additional four digits.

Account numbers in our system now have a zero (0) in front of the original seven-digit account number without the L or M preceding the number. For example, if your account number is L12-34567-0000, your number will be 01234567.  Businesses that hand fill-in returns should use the appropriate business location number for a return. For example, use 012345670001 for your location -0001.



  • Most businesses will experience little or no change in how they file. Taxpayers who correctly complete returns will see less correspondence and fewer billing notices from the Department of Revenue. However, taxpayers will receive billing notices if their returns contain errors; if a required column is not completed; or if a payment does not match the amount due. Clean, error-free and timely-filed tax returns will reduce the number of letters and bills from the department.


  • No major changes are anticipated for the Colorado sales tax return (DR 0100). However, businesses with more than one location will file a separate return for EACH of the business’s locations -- reporting all taxes for that location, including state sales tax and Regional Transportation, Scientific and Cultural, and Football special districts. The locations will not be combined on one sales tax return. This method of filing is an option for those businesses that previously used spreadsheets and do not want to use the department’s electronic filing method. The DR 0100 return has a check box to be marked when taxpayers are filing an amended return.


Colorado NetFile, a free, online filing method for individual income tax, went to the new look on October 18, 2010. The forms in NetFile now look just like the Colorado 104, 104CR and 104PN returns and the service is easier to use.

In November 2009, the following were moved to the new system:

  • Individual income tax form 104 and related forms
  • Corporation income tax form 112 and related forms
  • Partnership income tax form 106 and related forms
  • Fiduciary income tax form 105 and related forms

In November 2008, the following were moved to the new system:

  • PTC (Property Tax Rent/Heat Rebate) form 104PTC
  • Severance tax form DR 0021
  • Other forms related to severance tax

How will this affect you?
The transition to the new system for income tax will bring about change to the way we work within the department in hopes that this will translate positively to the taxpayer.  The department has more than five million income tax accounts (individuals, corporations, partnerships, estates/trusts).  In the meantime, we ask for your patience as we transition, including response times similar to peak filing periods during not only the technical cutover in October 2009, but also the first few months of the new system as our employees adjust. 


You may notice improvements such as an ability to provide better customer service and a new look to our letters and forms as they are issued from the new system. 


For information about how to avoid filing errors that will be detected by the new system, see Common Filing Errors on Income Tax Returns.


Additionally, to improve confidentiality we have created a link between the Federal Employer Identification Number (FEIN) and a new 8-digit number called your Colorado Account Number.  This way, for each tax type we can use the Colorado Account Number rather than your FEIN.  The new account number will be referenced on all documentation you receive from us.  Don't worry, if you use any old account numbers.  We will still be able to process correctly the information you send to us.


And finally, for any taxes not filed/paid you will receive a monthly "Statement of Account (SOA)."  This document provides a consolidated notice informing the taxpayer of all periods in debt including those previously billed from our older computer systems but not yet collected. For each period the SOA will show the tax due, interest, penalty, additions to tax, and any credits. In cases of non-filed tax returns, it will show estimated tax due. It will also show stages of collection, such as an assessment, notice of proposed tax lien, or lien and distraint warrant.  Taxpayers will receive a separate SOA for each tax account (tax type) included in the new system. However, for tax types not included in the first phase, taxpayers will continue to receive billings and delinquency notices for non-filed returns as they have in the past.


What if I have questions about my account(s)?

We intend to make this transition as seamless as possible. However, if you receive something from us you believe to be in error or you do not understand, please call us at (303) 238-SERV (7378).


For Income Tax Forms

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