Condo Master Lot vs Unit Lot: Why a Title Search Shows 40 Mortgages
NYC condo unit lots run 1001-6999; the master (billing) lot runs 7501-7599. Searching the wrong one puts every neighbor’s mortgage on your report.
Quick answer
A NYC condominium has two kinds of tax lot: unit lots numbered 1001–6999, one per apartment, and a billing or master lot numbered 7501–7599 covering the whole complex. Searching at building scope returns every unit’s mortgage, so a report showing 40 mortgages on one condo unit is a scope error, not a lien problem.
What is a condo master lot?
New York does not treat a condominium building as one parcel. Real Property Law § 339-y provides that each unit and its common interest "shall be deemed to be a parcel and shall be subject to separate assessment and taxation," and expressly excludes the building, the property and the common elements from separate-parcel treatment.
So the Department of Finance issues every apartment its own tax lot. The NYC Department of City Planning PLUTO Data Dictionary states the ranges directly: "These unit lot numbers have values between 1001 – 6999. Each unit tax lot has an associated billing lot number, with values between 7501 – 7599." A 95-unit building therefore occupies 95 separate lot numbers on one tax block.
There is a third number practitioners hit constantly and almost no guide mentions: the base lot, also called the "formerly known as" or FKA lot. That is the original pre-condominium tax lot. The Department of Finance, which documents the base lot in its condominium-within-a-condominium recording guidance, still carries the base lot geography on the Digital Tax Map, and City Planning swaps the base lot number for the billing lot number when it builds MapPLUTO. Three numbers, one building, and only one of them is the parcel a unit buyer is acquiring.
Definition
Condo master lot (billing lot) — A condo master lot is the single tax lot the NYC Department of Finance assigns to an entire condominium complex for billing purposes. City Planning documents billing lot numbers in the range 7501–7599. Every unit lot in that complex on the same tax block shares one billing lot number.
How do I tell a master lot from a unit lot?
Read the last four digits of the BBL. The lot number alone tells you the scope of any search run against it, before you look at a single document.
| Lot number | What it is | What a search against it returns |
|---|---|---|
| Under 1000 (typical) | Ordinary tax lot, or the base / FKA lot of a converted building | Pre-declaration instruments and some building-wide filings, not unit-level title |
| 1001–6999 | Unit lot — one apartment, office floor, retail space or parking unit | That unit’s deed, mortgages, assignments and satisfactions. This is the lot you want |
| 7501–7599 | Billing lot, commonly called the master lot — the whole complex | Very little. It is an accounting key, not a recording index |
| 8000–9989 | Subterranean and air lots, published by DOF as separate Digital Tax Map layers | Separate encumbrances that may not appear on the ground parcel |
Why does a title search show 40 mortgages on one condo unit?
Because the search ran at building scope instead of unit scope. Every mortgage taken by every owner in the building is recorded against that owner’s own unit lot. Roll all the unit lots together into one result set and you get the building’s entire borrowing history presented as if it encumbered a single apartment.
Here is the effect on a real building, using public data anyone can re-run. 100 East 53rd Street in Manhattan sits on tax block 1307. Query the ACRIS Real Property Legals dataset for that block’s condominium unit lot range — borough 1, block 1307, lots 1001 to 6999, no address filter — and it returns 100 distinct unit lots carrying 1,094 distinct documents. Restrict it to the 95 of those unit lots that ACRIS indexes under the street name EAST 53RD STREET and the lot-scoped count is still 975 documents, among them 97 deeds and 44 mortgages. A search of one unit lot — lot 1104 — returns 49 documents: one deed, six mortgages, and the assignments and releases that go with them. Same building, same afternoon, two completely different reports. (Counts queried 18 August 2026.)
Now run the fallback the wrong way round, as an address-string search rather than a lot search. Filter those same 95 unit lots on the address string "EAST 53RD STREET" — the exact spelling — and the result collapses to 844 documents, 87 deeds and 36 mortgages — 131 documents, ten deeds and eight mortgages fewer than the lot-scoped answer for the identical lots. The missing instruments are indexed under "EAST 53 STREET" (112 documents), "LEXINGTON AVENUE" (16) and three further one-off spellings. Widening the scope inflates the count; matching on the address string quietly deflates it. Only the lot number is stable.
Those are counts of recorded instruments, not open liens. Many of the 44 mortgages have been satisfied: across those 975 documents the dominant types are partial releases (541) and releases (126), not mortgages. Counting mortgage documents is not the same as counting encumbrances, which is a second failure mode layered on top of the first.
The scope error is usually a fallback rather than a deliberate choice. Geocode a plain street address with no unit number and you generally get the condominium’s billing lot, because PLUTO stores the billing lot as the BBL for a condominium — the data dictionary says so outright: "For condominiums, the BBL is for the billing lot." Search ACRIS on that BBL and you get nothing back. Block 1307 has no lot in the 7501–7599 range in ACRIS at all. An empty result looks like a bug, so the tool widens to the block or the street number, and the widened search sweeps in the other 99 unit lots.
Why does the master lot show zero deeds?
Because nobody ever conveys it. Section 339-y makes each unit and its common interest the parcel, and expressly excludes the building, the property and the common elements from that treatment. An owner’s share of the lobby, roof and mechanicals passes automatically with the unit deed. There is no separate instrument to record, so there is no deed to find.
The billing lot is an accounting construct rather than a recording index, and the record reflects that. Across the whole of ACRIS — four boroughs, 1966 to the present — tax lot 7501 appears on only 217 distinct documents citywide. For most condominium complexes the billing lot never appears in the land records at all.
So an empty master lot result is the correct answer to the wrong question. A report that says "no deeds found" on a 75xx lot has not failed to locate the deed; it searched a lot that never had one. The dangerous version is the report that reads that emptiness as a clean chain of title and says nothing about scope.
How to search the correct lot for a condominium unit
Get the unit-level BBL, not the building BBL
Geocoding a street address without a unit number usually returns the complex’s billing lot. Look the address up together with the unit designation in the NYC Property Information Portal to get that unit’s own 10-digit BBL.
Read the lot number before you run anything
1001–6999 is a unit. 7501–7599 is the whole complex. Under 1000 is an ordinary lot or a pre-condominium base lot. If you are holding a 75xx lot, you do not yet have the parcel your buyer is acquiring.
Search ACRIS by BBL on the unit lot
ACRIS covers Manhattan, Brooklyn, the Bronx and Queens from 1966 to the present. Staten Island falls outside that document-search coverage and has to be researched separately, which matters because Staten Island has condominiums too.
Expect the declaration on every unit
The declaration (ACRIS document type CDEC), its amendments (ADEC) and the condominium plans (MAPS) are indexed against every unit lot in the complex. On block 1307 a single 2018 declaration document is indexed against 96 lots. Seeing it on your unit is correct behavior, not duplication, and it is not a lien.
Match satisfactions to mortgages before counting anything open
Releases and partial releases outnumber every other document type on an active condominium block. A count of mortgage documents is not a count of live encumbrances until each one has been paired with its satisfaction or release, or shown to have none.
Watch the street name if you ever fall back to an address search
ACRIS holds the same building at 100 East 53rd Street under both "EAST 53RD STREET" (844 documents on the unit lots) and "EAST 53 STREET" (112). A string-matching address fallback that hits one spelling silently drops every document filed under the other — that is where the 131 missing documents above went.
Which instruments actually attach to a single condo unit?
Once you are searching the right lot, the remaining question is which of the returned instruments burden the unit and which are building-wide records that merely appear in its index.
| Instrument | Where it is indexed | Burdens one unit? |
|---|---|---|
| Unit deed | The unit lot | Yes — this is the chain of title you are verifying |
| Purchase-money or refinance mortgage | The borrower’s unit lot | Yes — that unit only, never the neighbors |
| Declaration (CDEC) and amendments (ADEC) | Every unit lot in the complex | No — governing document, not an encumbrance |
| Condominium plans (MAPS) | Every unit lot | No — building-wide record |
| Sponsor or construction blanket mortgage | The base lot, and unit lots not yet released | Only until that unit is released — look for the partial release |
| Common charge lien by the board of managers | The specific unit in arrears | Yes — RPL § 339-z gives the board "a lien on each unit for the unpaid common charges thereof" |
How HeritageDeed handles master lots
HeritageDeed classifies the BBL before it searches anything. A lot in the master range is flagged as building scope, and the report carries an explicit notice saying so rather than presenting building-wide results as unit-level findings. Where the only available data is building scope, the deed chain is narrowed to the unit’s own chain of title and the report says that narrowing happened.
The honest limit: unit-level filtering leans on matching the owner to the grantee on the unit deed. Where a unit is held by an LLC that later changed names, or where an ACRIS party name is misspelled at recording, that match degrades. The report states which scope produced the answer so a reader can tell a clean unit search from a filtered building search. Handling this correctly is a real differentiator against tools that scrape the same public sources and never check the lot range — it is not magic, and it does not make a search into something it is not.
One boundary, stated plainly: HeritageDeed sells title searches, not title insurance. It does not underwrite and it does not issue policies. A buyer taking a mortgage cannot close on a search alone — the lender requires a policy from a title insurer, a distinction worked through in title search vs title insurance. HeritageDeed reports cost $49, $79 and $129 and are delivered as both a PDF and structured JSON, which is what makes a scope flag machine-readable rather than a sentence someone has to notice.
Key takeaways
Key takeaways
- NYC condominium unit lots are numbered 1001–6999; the billing or master lot is 7501–7599. The lot number alone tells you the scope of a search.
- A report showing dozens of mortgages on one apartment is a building-scope false positive, not a lien problem. Check the BBL before the lien schedule.
- A master lot with zero deeds is correct. RPL § 339-y makes the unit the parcel and excludes the common elements, so the master lot is never conveyed.
- Geocoding an address without a unit number returns the billing lot, because PLUTO stores the billing lot as the BBL for a condominium. That empty result is what triggers most bad fallbacks.
- The declaration, its amendments and the condominium plans appear on every unit lot in the complex. They are governing documents, not encumbrances.
- Mortgage document counts are not encumbrance counts until each mortgage is matched to its satisfaction or release.
Frequently asked questions
- What is the difference between a condo master lot and a unit lot in NYC?
- A unit lot is the tax lot for one apartment, numbered 1001–6999, and it carries that unit’s deed and mortgages. The master or billing lot, numbered 7501–7599, is the Department of Finance’s billing key for the whole complex and is rarely used to index recorded documents at all.
- Why does my NYC condo title search show 40 mortgages?
- The search ran at building scope. Every owner’s mortgage is recorded against their own unit lot, so a search that sweeps a whole block or every unit lot in a building returns the neighbors’ loans alongside yours. On Manhattan block 1307, a search rolled up across the 95 unit lots of one condominium returns 44 mortgage documents; the correct search of a single unit lot returns six.
- Is it a problem that the condo master lot has no deed?
- No. Under NY Real Property Law § 339-y each unit and its common interest is the parcel, and the building, property and common elements are expressly excluded. The common elements are never conveyed separately, so no deed is ever recorded against the master lot. Zero deeds there is the correct result.
- What lot number range are NYC condo unit lots?
- The NYC Department of City Planning PLUTO Data Dictionary states that condominium unit lot numbers have values between 1001 and 6999, and that each unit tax lot has an associated billing lot number between 7501 and 7599. All units of one complex on a tax block share the same billing lot number.
- How do I find the unit BBL for a condo apartment?
- Look up the street address together with the unit designation in the NYC Property Information Portal, which returns the unit’s own 10-digit BBL. Geocoding the street address alone generally returns the complex’s billing lot, because PLUTO stores the billing lot as the BBL for a condominium.
- Why does the condominium declaration appear on my unit search?
- Because it is indexed against every unit lot in the complex. On Manhattan block 1307 one 2018 declaration document is indexed against 96 separate lots. The declaration and its amendments govern the unit but are not liens, and a report that lists them as encumbrances is miscategorizing them.
- Does searching the correct unit lot replace title insurance?
- No. A title search reports what is in the public record; a title insurance policy is an indemnity contract issued by an insurer. HeritageDeed does not sell or underwrite title insurance. A buyer taking a mortgage cannot close on a search alone, because the lender requires a policy.
- Does the master lot problem also affect co-ops?
- Differently. A co-op building is a single tax lot owned by the corporation, and shareholders hold shares and a proprietary lease rather than real property. Co-op unit financing is secured by UCC filings against the shares, not by mortgages recorded against a unit lot, so ACRIS lot searching does not surface it.
Sources
Primary records and official documentation cited in this article.
- 1PLUTO Data Dictionary (May 2026, 26v1) — condominium unit and billing lot ranges — NYC Department of City Planning
- 2NY Real Property Law § 339-y — Separate taxation of condominium units
- 3NY Real Property Law § 339-z — Lien for common charges
- 4Processing and Recording a Condominium-within-a-Condominium (base lot / FKA lot) — NYC Department of Finance
- 5ACRIS — coverage and property search — NYC Department of Finance
- 6ACRIS Real Property Legals — NYC Open Data (dataset behind the lot-level counts above)
- 7NYC Property Information Portal — unit-level BBL lookup — NYC Department of Finance
HeritageDeed provides public-record search reports only. Reports do not constitute title insurance, an attorney opinion of title, or a title insurance commitment.