Pennsylvania Just Flipped How Local Sales Tax Works. Enforcement Starts October 1
Pennsylvania just made a fundamental change to how local sales tax works — and enforcement starts in 10 days.
As part of Pennsylvania's fiscal 2026-2027 budget, Act 21 of 2026 shifts local sales taxation for Philadelphia and Allegheny counties from Pennsylvania's long-standing origin-based sourcing methodology to a destination-based approach. The law took effect July 12, 2026 — but the Pennsylvania Department of Revenue gave businesses until October 1, 2026 to update their systems before enforcement begins.
That grace period ends in 10 days.
If you sell taxable products or services into Pennsylvania and you ship to Philadelphia or Pittsburgh addresses, your compliance obligation just changed — retroactively to January 1, 2026. Here's exactly what changed, who's affected, and what you need to do before October 1.
What Changed — Origin vs. Destination Sourcing
This is the core of the story — and it's a bigger deal than most businesses realize.
Pennsylvania has always been a state with two local sales taxes layered on top of its 6% state rate. Philadelphia adds 2%, creating an 8% combined rate. Allegheny County — home of Pittsburgh — adds 1%, creating a 7% combined rate. Every other Pennsylvania address is just the 6% state rate.
Before Act 21, those local taxes were collected based on the seller's location — origin sourcing. A Philadelphia-based seller charged Philadelphia's 2% on all their Pennsylvania sales, even deliveries to customers in Lancaster or Erie. A seller based in Lancaster charged only the 6% state rate on deliveries to Philadelphia customers.
As the City of Philadelphia's Department of Revenue explained in its September 8 guidance, under the new rules businesses outside Philadelphia that already collect Pennsylvania's 6% state tax must now also collect Philadelphia's 2% tax when they ship taxable items to Philadelphia addresses.
The rate didn't change. The logic of who collects it completely flipped.
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The New Pennsylvania Rate Structure Starting October 1
Under Act 21 of 2026, the applicable sales tax rate for any Pennsylvania transaction depends entirely on where the product is delivered — not where the seller is located. As RKL LLP's analysis of Pennsylvania's local sales tax sourcing changes confirmed, the new framework works as follows:
8% for deliveries to Philadelphia — 6% Pennsylvania state sales tax plus 2% Philadelphia local tax. 7% for deliveries to Allegheny County — 6% Pennsylvania state sales tax plus 1% Allegheny County local tax. 6% for deliveries everywhere else in Pennsylvania — Pennsylvania state tax only.
This applies to every vendor required to collect Pennsylvania's 6% state sales tax — including remote sellers with Pennsylvania economic nexus. Pennsylvania's economic nexus threshold is $100,000 in annual Pennsylvania sales. Cross that threshold anywhere in the state and you have a collection obligation — and under Act 21, that obligation now includes the correct local rate for every Philadelphia and Allegheny County delivery.
Who Is Affected — And Who Isn't
As BDO's analysis of Pennsylvania's destination-based local sales tax sourcing confirmed, the change affects several distinct categories of sellers.
Remote sellers outside Pennsylvania who have crossed Pennsylvania's $100,000 economic nexus threshold and are already collecting the 6% state rate now need to also collect 8% on Philadelphia deliveries and 7% on Allegheny County deliveries. If you've been collecting 6% on all Pennsylvania deliveries regardless of destination — you've been under-collecting on Philadelphia and Allegheny County orders since January 1, 2026.
Pennsylvania sellers outside Philadelphia and Allegheny County who ship to customers in those jurisdictions face the same obligation. A business in Lancaster, Harrisburg, or Erie shipping taxable goods to a Philadelphia customer now owes the 2% Philadelphia local tax on that transaction.
Philadelphia and Allegheny County sellers shipping to other Pennsylvania addresses face the mirror-image change. Previously they collected local tax on all Pennsylvania sales. Under Act 21, they collect only the 6% state rate on deliveries outside those counties — a rate decrease on some transactions.
Marketplace facilitators collecting Pennsylvania sales tax on behalf of sellers need to handle the destination-based local tax correctly. If your marketplace platform is handling Pennsylvania collection, verify it's applying 8% to Philadelphia deliveries and 7% to Allegheny County deliveries from October 1.
The Retroactive Effective Date — What It Means
This is the compliance detail generating the most questions — and the most anxiety.
The law applies retroactively to tax years after December 31, 2025. That means technically, the new destination-based sourcing has applied since January 1, 2026 — not October 1. But the Pennsylvania Department of Revenue announced it will not begin enforcing the new requirements until October 1, giving businesses nine months to adjust.
As the international sellers guide from Sterlinx Global noted, businesses should not treat the enforcement delay as a cancellation of the earlier legal period. Review your 2026 transactions and keep clear records of how you assessed and handled the January-to-September period.
The practical guidance from most tax professionals: don't rush to amend January through September returns proactively unless you have specific guidance from the Pennsylvania Department of Revenue. Focus on getting your systems correct for October 1 — and if your historical calculations during the January to September period appear incorrect, document the issue and obtain current instructions from the Department of Revenue before correcting filings or remitting additional tax.
The Allegheny County Angle Most Businesses Are Missing
Coverage of Act 21 has focused almost entirely on Philadelphia — understandably, since it's the bigger city and higher rate. But Allegheny County deserves equal attention.
Allegheny County includes Pittsburgh — Pennsylvania's second-largest city with roughly 300,000 residents and a much larger metro area. Remote sellers shipping taxable goods to Pittsburgh addresses have the same October 1 obligation as those shipping to Philadelphia: apply the 1% Allegheny County local tax on top of the 6% state rate for a 7% combined rate.
For ecommerce sellers with significant Pennsylvania customer volume, Allegheny County likely represents a meaningful share of your delivery addresses. The rate change there is smaller — 1% vs. 2% for Philadelphia — but the compliance obligation is identical. Both counties flip to destination-based sourcing on October 1.
What to Do Before October 1
Ten days is enough time to handle this — if you start today. Here's the action list.
Identify your Philadelphia and Allegheny County customer addresses. Pull your Pennsylvania order history and flag every delivery address in Philadelphia County and Allegheny County. These are the transactions where your rate calculation changes on October 1.
Update your tax calculation system. Your ecommerce platform, POS system, or tax engine needs to apply 8% to Philadelphia deliveries and 7% to Allegheny County deliveries starting October 1. If you use Avalara, TaxJar, Vertex, or another automated tax engine — verify the update has been applied for Pennsylvania destination-based sourcing. Most major platforms have already updated their Pennsylvania logic for Act 21. Confirm rather than assume.
Validate your customer address data. Destination-based sourcing only works correctly if your system knows where the customer is receiving the goods. Incomplete or incorrect address data creates incorrect rate calculations. This is particularly relevant for B2B sellers where ship-to addresses may differ from billing addresses.
Review your Pennsylvania filing. Pennsylvania uses a centralized filing system — all sales tax is reported on a single return regardless of which jurisdictions you collected for. The Form PA-1 return has been updated to capture local tax collected separately from state tax. Verify your filing system generates the correct return format for post-October 1 periods.
Check your contracts and invoicing. If you have contracts with Pennsylvania customers that quote an all-in price or a specific sales tax rate, review whether Act 21 changes the rate you're required to collect on those transactions. Customers receiving deliveries in Philadelphia or Allegheny County may see a rate change on their invoices from October 1.
October 1 Is Also D.C.'s Rate Change Day
One more timing note worth flagging for businesses with complex multi-state compliance.
October 1 is simultaneously the enforcement start date for Pennsylvania's Act 21 AND the effective date for Washington D.C.'s rate increase from 6.5% to 7%. Businesses selling into both Pennsylvania and D.C. face two separate compliance updates on the same day.
We covered D.C.'s October 1 rate change in detail in our Washington D.C. sales tax rate change article.
Not sure whether your Pennsylvania tax calculation is correctly configured for Act 21's destination-based sourcing before October 1 - or need help identifying which of your Pennsylvania customer addresses fall in Philadelphia or Allegheny County? Book a free consultation with our team at sales.tax. We'll verify your Pennsylvania setup and make sure you're collecting the right rate for every delivery address from October 1.
What this means for your business
If your sales into Pennsylvania have grown with prices, you may have crossed the economic nexus threshold without changing anything about how you sell. We’ll tell you where you stand in 30 minutes — and if there’s nothing to fix, we’ll say so.