Day 0 to day 90: the building becomes vacant by law
A DC property counts as vacant once it has been unoccupied for 90 days. Nothing arrives in the mail on day 90. The status simply attaches, and from that point the owner is expected to register the building with DOB under D.C. Code §42-3131.05, pay the registration fee, or file for an exemption. The fee is set by D.C. Code §42-3131.09: $350 for the initial registration and $500 for each renewal, and the Mayor can raise both by rule. Most owners do none of these, because no one told them the clock had started. That is the first fork in the timeline: an owner who registers or files an exemption before DOB ever visits controls the record. An owner who waits gets a record written by an inspector.
The inspection: unannounced, and usually short
DOB inspections of suspected vacant buildings come from complaints, from routine sweeps, and from the District's own data on utility shutoffs and mail. The inspector parks, walks the front and the alley, photographs the building, and notes the signs: no curtains, stacked mail, no lights, overgrowth, boarding. The owner is not notified in advance and rarely knows the visit happened. Our article on what the inspector looks for covers the visit itself. On the timeline, the inspection date matters for one reason: it is the date the designation is anchored to, and every exemption or occupancy claim will be judged against what was true on that day.
The notice: the 15 day clock starts on the letter date
Some time after the inspection, DOB mails a designation notice to the owner of record at the address OTR has on file. The notice states the designation, the case number, and the owner's right to respond. The response window is 15 days from the date on the notice. This is the shortest and most consequential clock in the process. If the notice went to an old address, a former owner, or a relative who has died, the 15 days ran anyway. Owners who keep an accurate mailing address on MyTax.DC.gov catch this letter. Owners who do not find out from the tax bill months later.
Inside the 15 days, the owner files the Vacant Building Response Form, either claiming the building is occupied or claiming one exemption with its document attached. Our exemption form guide covers the categories and their time limits. Filed on time with the right attachment, this is often the last step an owner ever has to take.
Days 15 to 75: the determination window
After a petition is filed, the District has 60 days to issue a final determination. During that window DOB may reinspect or request documents. Owners should treat every request as having a deadline of today. A determination in the owner's favor updates the DOB record, and DOB notifies OTR. A determination against the owner opens the next stage, a 45 day window to appeal to the Real Property Tax Appeals Commission. Our step by step appeal article covers those stages. Exemption decisions on a complete filing generally come back in 60 to 120 days.
DOB to OTR: the handoff nobody sees
The designation on its own does not cost anything. The cost arrives when DOB transmits the designation to the Office of Tax and Revenue, and OTR changes the tax class on the property under D.C. Code §47-813. The two agencies keep separate records, and they do not always agree. A building can be vacant on the DOB dashboard and still Class 1 at OTR for a period, or corrected at DOB and still Class 3 at OTR. Checking both is a two minute job that our article on the DC vacant property list walks through. On the timeline, this handoff is why a designation issued in one month may not show up on a bill until the next half year.
The bill: half years, due March 31 and September 15
The DC tax year runs October 1 through September 30 and is billed in two halves. The first half is due March 31 and the second half is due September 15. Classification changes apply by half tax year, not by the day. Under §47-813(d-1), a new Class 3 or Class 4 classification is retroactive to the half tax year in which the owner registered the building as vacant or received DOB's notice of final determination, whichever came first. So the vacant rate can reach back to the start of the half you are already in, and OTR bills the difference on the next bill it issues. On a $500,000 assessment, that first Class 3 half is $12,500 instead of about $2,125, a difference of $10,375 for a single period. If the building was also getting the homestead deduction, the deduction and the assessment cap credit come off at the same time, so the jump owners see is often larger than the rate alone explains.
Putting the calendar together
Take an owner whose tenant moved out on January 15. The building is vacant by law around mid April. An inspector visits in June and the notice is dated July 1. The response window closes July 16. If the owner files on time and wins, the DOB record never reaches OTR as a vacant designation and the September 15 bill is unchanged. If the owner misses the window, DOB transmits the designation, the Class 3 rate attaches to the half tax year in which the determination became final, and the owner learns about it when the next bill arrives. Either way, the interval from the first empty day to the first vacant rate bill is typically well under a year, and the only point in that interval where the owner holds the initiative is the 15 days after the notice.
What still works after the first bill
A bill at the Class 3 rate is not final. The designation can still be corrected through the DOB route, and when it is, OTR corrects the period and the difference comes back as a refund or credit. Refund claims have a time limit measured from the date of payment, so the window to recover an overpaid period does eventually close. Pay the bill while the correction is pending. An unpaid half accrues penalty and interest, and the unpaid balance is what feeds the annual tax sale.
If your timeline has already reached the bill, send us the address. We pull the DOB record and the OTR bill for free and tell you which periods can still be corrected. Our fee is a flat $1,500 per tax period corrected, paid up front. If OTR does not correct a period, the $1,500 for that period is refunded in full.