New State Sales Tax Setup Checklist
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A step by step checklist for the moment your online store picks up nexus in a new state, from confirming the trigger to filing the first return.

[ ] Confirm what created nexus in this state: a physical trigger (location, inventory in a warehouse, employee, contractor) or an economic threshold, and write down the date it started.
[ ] Look up the state's own dollar and transaction thresholds and note which sales count toward them (gross or taxable, and whether marketplace orders are included).
[ ] Check whether the state is a home rule state where some cities or parishes administer their own sales tax and may require a separate local registration.
[ ] Gather the registration details: federal employer identification number, business structure, industry code, the date you began selling into the state, and an estimate of monthly taxable sales.
[ ] Decide whether to register directly with the state department of revenue or through the Streamlined Sales Tax registration if the state participates.
[ ] Register for a sales tax permit before you collect a single dollar of tax in the state; collecting without a permit is a violation in most states.
[ ] Record the permit number, portal login, assigned filing frequency, and first due date in your state tracker.
[ ] Categorize your catalog for this state: which items are fully taxable, reduced rate, or exempt (clothing, groceries, digital goods, and supplements are common exceptions).
[ ] Confirm whether separately stated shipping and handling charges are taxable in this state.
[ ] Confirm whether the state applies origin or destination sourcing to your orders, since in-state shipments can follow a different rule than remote ones.
[ ] Switch on collection for the state in your checkout and make sure rates come from address-level jurisdiction data, not from ZIP codes.
[ ] Place a few test orders to addresses in different counties and cities within the state and check the combined rate shown on each invoice against a current lookup.
[ ] Set up a process for collecting and storing exemption certificates from wholesale, resale, and nonprofit buyers before you honor an exemption.
[ ] Make sure marketplace orders shipped into the state are excluded from your own collection but still recorded for reporting and threshold tracking.
[ ] Add every due date for the state to a shared calendar with a reminder one week ahead, including zero returns for periods with no sales.
[ ] Open a separate ledger account or savings bucket for collected tax so it is never treated as revenue or spent.
[ ] Decide who files each return (you, a bookkeeper, or a filing service) and give that person access to the state portal now, not the week it is due.
[ ] Check whether the state offers a timely filing discount and whether prepayments apply at your sales volume.
[ ] Review whether you sold into the state before registering, estimate the exposure, and consider a voluntary disclosure agreement before the state contacts you.
[ ] Write a one-page setup memo for the state: nexus trigger, registration date, rate source, taxability rules, shipping treatment, and filing schedule.
[ ] Schedule a quarterly review of rates and rules for the state, since state and local rates change several times a year.
[ ] While you are at it, re-run the threshold check for the neighboring states where your sales are growing fastest.