Starting November 1, how much tax will a box of diapers carry in Westminster? The honest answer depends on the store's address, specifically which side of the Adams and Jefferson county line it sits on.
Starting November 1, 2026, the City of Westminster stops charging its 4.25% sales and use tax on diapers, infant formula and feminine hygiene products, according to the city's announcement on The Westy. The city first listed a later start date, and early news coverage reported it. The city has since updated its announcement to November 1. The city expects the change to save families between $400,000 and $600,000 a year.
That is real money. Still, the 4.25% city rate is only one of several taxes on a Westminster receipt, and the others don't treat these products the same way in both counties.
Why Westminster Needed Its Own Ordinance
Colorado dropped its state sales tax on diapers, incontinence products and period products on January 1, 2023, but Westminster shoppers kept paying city tax on them because of how the state law was written. The Colorado Department of Revenue explains that the 2023 exemption applied to state tax. Statutory cities and counties could choose to adopt it, and self-collecting home-rule municipalities were not affected at all. Westminster collects its own sales tax. The state's rate publication lists contact information for home-rule cities, and Westminster's line gives a city office address on West 92nd Avenue. That puts Westminster's 4.25% outside the state exemption's reach. The only way to remove it was a city ordinance.
Few local governments moved quickly. In 2023, The Colorado Sun reported that only a few municipalities and counties had followed the state's lead, so most of the sales tax burden on these items stayed in place.
Westminster City Council took up Councillor's Bill No. 34 at its August 24, 2026 meeting. The bill amends Title IV of the municipal code to exempt these products from city sales tax. Citizen Portal's meeting summary reported that the first-reading vote was unanimous.
The City Rate Was the Biggest Tax Left on These Items
Colorado's January 2026 sales and use tax rate publication, the DR 1002, lists the taxes on a Westminster purchase:
- State: 2.9%
- Regional Transportation District: 1%
- Scientific and Cultural Facilities District: 0.1%
- Westminster: 4.25%
- County: 0.75% in Adams or 0.50% in Jefferson
On ordinary purchases, that adds up to 9.00% on the Adams side of Westminster and 8.75% on the Jefferson side.
Diapers and period products were already exempt from much of that before November. The Department of Revenue's guidance says the state exemption also covers the RTD and SCFD taxes. Here is how each layer applies to diapers and period products, based on the January 2026 DR 1002 exemption codes:
| Tax layer | Rate | Diapers and period products before Nov. 1 | After Nov. 1 |
|---|---|---|---|
| State of Colorado | 2.9% | Exempt since 2023 | Exempt |
| RTD | 1% | Exempt | Exempt |
| SCFD | 0.1% | Exempt | Exempt |
| Westminster | 4.25% | Taxed | Exempt |
| Adams County | 0.75% | Exempt | Exempt |
| Jefferson County | 0.50% | No exemption listed | No exemption listed |
On the Adams side, the city's 4.25% was the only tax still charged on these products. Once it goes away, the January 2026 table points to no remaining sales tax at all. On the Jefferson side, the table lists Jefferson County's 0.50% with no exemption codes, so that piece appears to stay.
The city puts the savings at about $69 a year on diapers alone, using the American Academy of Pediatrics' estimate of $936 in annual diaper spending, and up to $96 a year on infant formula. For comparison, 0.50% of that same $936 works out to about $4.68 a year. That's a small amount, but it means a Jefferson-side receipt likely won't show zero tax.
Where the County Line Shows Up at Checkout
The two counties don't split Westminster neatly. Two of the city's biggest shopping districts happen to sit on opposite sides.
The Westminster Economic Development Authority's second-quarter 2026 financial report shows the split. It lists collection fees paid to Jefferson County for the Mandalay Gardens urban renewal area, which the report labels Shops at Walnut Creek. It lists Adams County as the collecting county for the North Huron area around the 144th Avenue and I-25 interchange, which it labels The Orchard.
So, based on the January 2026 rate table, a pack of period products bought at Orchard Town Center after November 1 should carry no sales tax. The same pack bought near Shops at Walnut Creek, west of US 36, would still carry Jefferson County's 0.50%.
Infant formula is less clear-cut. Westminster's release says the existing state exemption already covers formula. Jefferson County's line in the January 2026 table lists no exemptions of any kind, so a Jefferson-side formula purchase may also still carry the county's 0.50%.
The DR 1002 is revised every January 1 and July 1. The figures above come from the January 2026 edition. To check a specific store, the state's Colorado Sales Tax Lookup shows the taxes and local exemptions for any address, including home-rule city exemptions.
What Counts, and What Happens When the Register Disagrees
Westminster's announcement names diapers, infant formula and feminine hygiene products. In the city's release, Councillor Obi Ezeadi also listed adult incontinence diapers among the items covered.
For the state-level and special-district exemption, the Department of Revenue's diapers guidance gives a practical list.
Qualifying products include:
- Cloth diapers
- Disposable diapers
- Diaper inserts and liners
- 2-in-1 incontinence and period pads
- Pads and liners for bladder leaks
Nonqualifying products include:
- Clothing suitable for general use
- Rash creams, soaps, cleaning solutions and lotion
- Sheets, bed and crib liners, and mattress covers
That list describes the state's rules. The definitions in Westminster's own ordinance govern the city's 4.25%, and the city's tax office is the place to ask about edge cases.
Expect a few register mistakes in the first week while retailers update their systems. The state guidance spells out what happens under state rules when a shopper and a retailer disagree about whether an item is exempt. The retailer collects the tax and gives the buyer a receipt listing the item, the price, the tax paid and a short statement of the exemption claim. The buyer can then ask the Department of Revenue for a refund. No exemption certificate is required. For the city's portion, Westminster handles its own tax questions, since it collects its own tax.
How Westminster Is Paying for It
The exemption costs the city revenue, and council said where the money comes from. Denver7 reported that the city covered the cost with savings from capital improvement projects that came in under budget. Ezeadi told the station, "There's always a creative way if you have the will to do it."
The same Denver7 report linked the exemption to a wider affordability push. Child care affordability has been added to the city's strategic plan, Westminster has changed zoning rules to make it easier to open daycares, and the city is working on a property tax rebate for child care providers. Mayor Claire Carmelia said in the city's release that "affordability is the number one concern for our residents."
Westminster's release puts the change alongside similar measures in Denver, Aurora, Boulder, Lafayette and Englewood. Broomfield, Thornton and Arvada aren't on that list, so a diaper run just across Westminster's city limits may still be taxed under a neighboring city's own rules.
This post is general information about how these taxes are structured. It isn't tax or legal advice. If you have a question about a specific purchase or business, check with the city's tax office or a tax professional.
If you're weighing a move within Westminster and want to know how the Adams and Jefferson sides compare on taxes, fees and the day-to-day costs that don't show up on a listing, call or email Audrey Michel. Audrey can go through the details for the specific addresses you're considering.
