Code: B101 (official violation code)
Description: It is a formal DOB violation code for doing construction or alteration work without a required permit. It is classified as an immediately hazardous “Class 1” condition.
Practical Meaning: If you see B101 on your summons it is very serious. Someone did construction, plumbing, electrical, or other building work in your home without first getting the proper permit. In that case you will usually need an architect or other licensed professional to help you legalize the work or undo it.
Where You May See It: You may see B101 on a summons or violation notice from DOB or OATH, in DOB NOW or BIS when you look up your property, or on letters from your architect, expeditor, or attorney when they explain your case. It can also show up in title reports or due‑diligence reports when you try to refinance or sell, because open Class 1 violations stay in city records until they are properly corrected and closed.
Why It Matters: B101 is important because it can bring high fines, including default penalties in the five‑figure range if you ignore the summons or miss the hearing. It can also delay or block future permits, refinancing, or a sale of the property until you file for the proper permits, pass inspections, submit a Certificate of Correction, and officially clear the violation with DOB and OATH.
Source: More about work without a permit