A letter arrives from the state department of revenue. It says you have unfiled sales tax returns, it names periods going back further than you expected, and it gives you a date. Most owners read it twice, put it on the corner of the desk, and call their CPA -- who then explains that they do tax returns, not sales tax filings, and that the books need to be current before anyone can file anything. That exchange is where weeks get lost. A sales tax notice is not a tax-preparation problem. It is a books-mess problem wearing a tax-authority envelope, and the first move is getting the underlying sales data into a filable state.
The reason this catches owners out is that sales tax runs on a different calendar and a different system from income tax. Income tax is annual and your CPA owns it. Sales tax is monthly or quarterly, it is filed with the state rather than the IRS, it is calculated from your own sales records, and nobody owns it unless someone was specifically assigned to. In a lot of $500K-$10M businesses, the person who used to file it left, or the point-of-sale system changed, or the business started shipping into a second state, and the filings quietly stopped.
Why the First Instinct Is Usually the Wrong One
The instinct is to call the CPA, because the envelope came from a tax authority and CPA means tax. This is the tax-authority misdiagnosis, and it is the most expensive one in this category because of how much time it burns before anyone does the actual work.
A CPA can absolutely handle a sales tax matter, and for anything involving negotiation with the state you want one. What a CPA cannot do is conjure the data. Filing a back sales tax return requires knowing, for each period, what you sold, how much of it was taxable, which jurisdiction it was taxable in, and how much tax you actually collected at the register or at checkout. If your books are six months behind, or your ecommerce platform and your accounting file disagree, that information does not exist in a usable form yet. Somebody has to build it first, and that somebody is usually a cleanup bookkeeper or a sales tax specialist, not a CPA at CPA rates.
The second wrong instinct is to assume the software already handled it. A point-of-sale system or an ecommerce checkout calculates and collects sales tax. It does not file returns, it does not register you in new states, and it does not notice when you crossed an economic nexus threshold in a state you have never been to. This is the software misdiagnosis in its sales tax form: the collection worked, the filing did not, and the gap between those two is what the notice is about.
What Each Provider Type Actually Does Here
Sales tax cleanup is unusual because it needs more than one kind of help, and owners lose time by hiring one person and expecting all of it.
| The Work | What It Involves | Who Actually Does It | Typical Range |
|---|---|---|---|
| Rebuild the sales data by period and jurisdiction | Reconcile point-of-sale or platform reports to the books; separate taxable from exempt sales | Cleanup bookkeeper or QuickBooks ProAdvisor | $80-$90/hr; light cleanup $1,500-$3,500 |
| Determine where you owe | Nexus review: physical presence plus economic thresholds per state | Sales tax specialist or CPA with state-tax practice | Project fee, varies by state count |
| Register in states where you should have been filing | State registration applications, effective dates | Sales tax specialist | Per-state fee |
| Prepare and file the back returns | One return per period per jurisdiction | Sales tax specialist or bookkeeper with filing experience | Per-return fee |
| Negotiate penalties or a voluntary disclosure agreement | Abatement requests; VDA where you are not yet registered | CPA or state-tax attorney | Hourly |
| Keep it from recurring | Filing calendar, assigned owner, monthly reconciliation | Bookkeeper, ongoing | $200-$600/mo ongoing bookkeeping |
Bookkeeping and cleanup figures above are the ranges used across this library and are typical ranges, not quotes. Sales tax specialist and registration fees vary too much by state count and filing frequency to range usefully, so they are left out rather than invented -- get two quotes once you know how many states and periods are actually involved.
What the Cleanup Bookkeeper Will Not Do
Scope this before you hire, because the second misdiagnosis happens here. A cleanup bookkeeper will reconstruct and reconcile your sales records, match them to deposits, and get the file to a point where returns can be prepared. Most will not perform a multi-state nexus determination, will not file registrations on your behalf, and will not represent you with the state. Those are separate engagements with separate people.
Equally, a sales tax specialist will not fix the underlying accounting file. They work from the data you hand them. Hire the specialist first and you will pay them to wait, or worse, they will file from numbers that have not been reconciled -- which produces returns you may have to amend later.
The sequence that works is: reconcile the sales data, determine where you owe, register where needed, file, then negotiate what is left. Owners who run that sequence out of order are the ones still dealing with it nine months later.
When This Is Not the Right Path
If the notice is about payroll taxes rather than sales tax, stop and treat it as a different and more urgent problem. Payroll tax penalties compound faster and carry personal liability exposure that sales tax generally does not. That is the payroll-compliance path, and it moves on a shorter clock.
If you are registered, current, and the notice is a routine assessment or a rate question, this is not a cleanup project at all. Call the number on the notice or hand it to your existing bookkeeper.
And if the dollar amount is large, if several states are involved, or if the periods reach back more than about two years, bring in a CPA or state-tax attorney before you contact any state directly. Registering in a state where you already owe back tax, without first understanding whether a voluntary disclosure agreement is available, can cost you the relief you would otherwise have qualified for. That is a decision to make with advice, not on instinct.
The Decision Path
Start with three questions, in order.
Are the books current enough to know what you sold, by period and by state? If no, that is the first engagement and it is a cleanup bookkeeper. Everything else waits. Owners in this position are usually also behind on general bookkeeping, and the two jobs are done together -- see catch-up bookkeeping for how backlog size drives cost and timeline.
Do you know every state where you have an obligation? If you sell online, ship to other states, use a third-party fulfillment warehouse, or have remote staff, the answer is probably no. That is a nexus review, and it is a specialist question.
Is there an amount in dispute or a penalty worth contesting? If yes, a CPA or state-tax attorney handles the state, and the bookkeeper supports them with the records.
One more thing worth doing regardless of the answers: find out why the filings stopped. In most cases nobody was assigned to it after a staffing change, which means it will stop again as soon as this cleanup is finished. If a prior bookkeeper or service let this run for a year without flagging it, that is its own diagnosis -- see failed-provider for how to work out whether the relationship is recoverable.
Frequently Asked Questions
- Can my CPA just file the back sales tax returns?
- Some can, particularly CPAs with a state and local tax practice. Many general-practice CPAs do not file sales tax returns at all and will refer it out. Ask directly whether they file sales tax in the specific states involved before assuming it is covered, because this is the single most common place the work stalls.
- How far back do I have to go?
- That depends on the state and on whether you were registered. Registered businesses generally face a defined lookback; unregistered businesses can face a longer one, which is why voluntary disclosure agreements exist and why registering before taking advice can be costly. Confirm the specific lookback with a CPA or state-tax specialist for each state before filing anything.
- Do I owe sales tax I never actually collected from customers?
- Often yes. The obligation to remit generally does not depend on whether you charged the customer at the time, which is why a gap discovered late comes out of the business rather than out of the customer. This is the main reason sales tax backlogs get expensive quietly, and the main reason to fix the filing calendar rather than just the past periods.
- My books are a mess and the notice has a deadline. What do I do first?
- Call the number on the notice or have a CPA call, and find out whether the deadline can be extended while records are reconstructed. States are frequently willing to allow time when someone is actively working the problem. Then start the bookkeeping cleanup immediately, because that is the long pole regardless of what the state says.
- Will a bookkeeper catch this before it happens again?
- Only if filing sales tax is explicitly in their scope. It is not a default bookkeeping duty. Put it in writing, name the states and the filing frequency, and ask for confirmation each period -- the same way you would for payroll filings.
Next Step
If you are not sure whether a sales tax notice means you need a cleanup bookkeeper, a sales tax specialist, or a CPA, the books-mess diagnostic walks through the state of your records and points at the right first engagement. It takes about three minutes and it is built for exactly this situation: an owner holding a deadline who does not yet know which kind of help to call.
Want a 1:1 review? Email [email protected] with the notice itself, the periods it covers, the states you sell into, how far behind the books are, and whether sales tax filing was ever assigned to anyone.
This article is informational and does not constitute financial, legal, or tax advice. Consult a qualified professional for decisions specific to your situation.