If the city has determined your property to be vacant, and you disagree, you will need to fill out DCRA's Vacant Property Response Form (PDF).
Before we get to the exceptions, the part where one checks "YES, MY BUILDING IS VACANT and I certify that it meets the Vacant Building Maintenance Requirements in D.C. Code 42-3131.12. Please REGISTER MY BUILDING AD VACANT. I will be taxed at the Class 3 rate." And there is a registration fee of $250.00. $250 on top of the higher rate, seems to create a dis-incentive to quickly register property.
Anyway, there are two other options to agreeing a property is vacant. The first is checking the box "NO, MY BUILDING IS OCCUPIED" and two most recent water and any other utility bills. If the building is commercial then add a Certificate of Occupancy. The second box is "MY BUILDING IS EXEMPT" and there are 5 options.
The first option is for buildings under active construction. Instructions read as "List building permit number(s). Permit(s) must have been issued, renewed, or extended within 12 months of the required registration date." The issuing of a permit doesn't always mean work done, but it is a legitimate exemption. Problems arise when work starts, and stops, and starts and stops over a lengthy amount of time. This is frustrating for neighbors, and probably no fun for the developer either.
The second is, "THE OWNER IS ACTIVELY SEEKING TO SELL OR RENT THE BUILDING". This requires, according to the form, a "listing agreement with realty agent contact information AND MRIS or MLS electronic listing." There is nothing saying the price has to be reasonable.
The third is, "THE BUILDING IS THE SUBJECT OF A PROBATE PROCEEDING OF THE TITLE IS THE SUBJECT OF LITIGATION." This requires proof of ownership, and a copy of a Letter of Assignment and court documents showing the case is active. Probate and court cases can take time.
Fourth is, "THE BUILDING IS THE SUBJECT OF A PENDING APPLICATION BEFORE A D.C. DEVELOPMENT BOARD". This requires a copy of a filed application for a hearing with a particular board or commission. This is another process that can take time.
Lastly is, "I AM SEEKING A SPECIAL EXEMPTION FROM THE MAYOR". This requires documentation. I have no idea what this is, but just seeking it seems to be an option, regardless of getting it.
There is nothing on the form as to how long an exemption to the Class 3 rate may continue.