12 William St, Cambridge, MA 02139 Property Records

Middlesex County and Cambridge City property record for 12 William St, Cambridge, MA 02139

Property Summary

Property Type	Duplex
Details	7 bd · 2.5 ba · 3,564 sqft · built 1873
Lot Size	0.103 acres (4,500 sqft)
Owner	2 Company Names on Record
Last Sale	$245,000 (May 1991)
Tax Bill	$16,688 (2025)
Deeds & Mortgages	Sep 2026 Transfer Nov 2021 Transfer
Flood Zone	Zone X (minimal risk)
APN	`106-5`

Property Details

APN / Parcel Number

Primary APN	`106-5`
Alternative APN	`CAMB M:00106 L:00005`

Interior

Bedrooms	7 Beds
Full Baths	2.5 Baths
Half Baths	1 Half Bath
Total Rooms	14 Rooms
Units	2 Units
Stories	3 Stories
Building Area	3,564 sqft Living Area
Gross Area	6,027 sqft
1st Floor Area	1,596 sqft
Basement Area	1,596 sqft
Unfinished Basement	1,596 sqft

Exterior

Year Built	Built 1873
Effective Year Built	Effective 1873
Architectural Style	Other
Exterior Material	Wood Siding
Construction Type	Brick
Roof Type	Gable
Roof Material	Asphalt
Lot Area	4,500 sqft (0.103 acres)
Parking Spaces	1 Parking Space
Deck Area	Deck Area

Utilities, Heating & Cooling

Cooling System	HVAC
Heating System	Hot Water
Heating Fuel	Oil

Location & Zoning

Street Address	12 WILLIAM ST
City	CAMBRIDGE
State	MA
Zip	02139-3916
Property Category	Residential
Property Type	Residential > Multi-Unit > Duplex
Local Zoning Code	C
Legal Lot Number	5
Jurisdiction	CAMBRIDGE MA
Township / Civil Division	CAMBRIDGE
Census Block Group	1
Census Block	1004
Census Tract	353300

Owner

Source: Middlesex County and Cambridge City records, as of October 20, 2026

Owner names and exact recorded amounts shown locked on this page are available instantly with a free trial.

Owner of Record	2 Company Names on Record
Mailing Address	12 WILLIAM ST, CAMBRIDGE, MA 02139-3916
Occupancy	Owner Occupied
Owner Type	Company
Vesting	Trust, Living Trust

Deeds, Mortgages & Sale History

Date	Document
Sep 23, 2026	Quit Claim Deed, Transfer Quitclaim
Nov 3, 2021	Quit Claim Deed, Transfer Quitclaim

Assessor's Deed Record

Deed Names	2 Names on Deed
Last Sale	May 10, 1991 · Amount on Record
Deed Sale	May 10, 1991 · Amount on Record
Deed Document Number	1991
Deed Book / Page	21150 / 274
Last Transfer Date	Aug 26, 2026
Transfer Doc	0000120648
Record Updated	Oct 29, 2026

September 2026: Quit Claim Deed, Transfer

Document Type	Quit Claim Deed
Jurisdiction	CAMBRIDGE MA
Recording Date	Sep 23, 2026
Property Address	12 WILLIAM ST, CAMBRIDGE, MA 02139-3916
Document Number	0000120648
Book / Page	86168 / 328
Instrument Date	Aug 26, 2026
Instrument	2026120648
Transaction Type	Transfer
Record Updated	Oct 14, 2026

Transaction

Tax	$0.00
Amount Accuracy	No Consideration Stated
Additional	Quitclaim Intrafamily Transfer

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Address	12 WILLIAM ST, CAMBRIDGE, MA 02139-3916

November 2021: Quit Claim Deed, Transfer

Document Type	Quit Claim Deed
Jurisdiction	CAMBRIDGE MA
Recording Date	Nov 3, 2021
Property Address	12 WILLIAM ST, CAMBRIDGE, MA 02139-3916
Document Number	079069-437
Book / Page	79069 / 437
Instrument Date	Nov 1, 2021
Instrument	241466
Transaction Type	Transfer
Record Updated	Oct 31, 2025

Transaction

Tax	$0.00
Amount Accuracy	No Consideration Stated
Additional	Quitclaim Intrafamily Transfer

Transferred From (Grantor/Seller)

Name	Verified Name

Transferred To (Grantee/Buyer)

Name	Verified Name
Address	12 WILLIAM ST, CAMBRIDGE, MA 02139-3916

Tax Assessment & Valuation

Source: Middlesex County and Cambridge City assessment roll, as of April 14, 2026

Property Jurisdictions

Type	Name
State	Massachusetts
County	Middlesex County
Municipality	Cambridge City
Unified School District	Cambridge School District (PK - 12)

Tax Bill & Assessment History

Year	Tax Bill	Assessed Value	Assessed Market Value
2025	$16,688.00 (+7.82%)	$2,628,100 (+0.53%) Land $1,072,600 Building $1,555,500	$2,532,380
2024	$15,477.00 (+9.23%)	$2,614,300 (+8.12%) Land $1,117,400 Building $1,496,900
2023	$14,169.00	$2,417,900 Land $1,106,200 Building $1,311,700

Assessed value and assessed market value are set for property tax purposes and are not market price estimates.

Flood

Source: FEMA National Flood Hazard Layer, effective September 10, 2026

FEMA Flood Zone	Zone X minimal risk
Flood Insurance Requirement	Not required lenders may require it

Values are read at the parcel center point; lenders make the official flood determination.

Wildfire

Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024

Wildfire Risk	Not rated no burnable land within ember reach

Values cover an area roughly 900 ft across, not the parcel itself; insurers use their own ratings.

Drinking Water

Source: EPA Safe Drinking Water Information System, as of September 2026

Water System	CAMBRIDGE WATER DEPARTMENT serves 118,214 people · EPA ID MA3049000
Water Source	Surface water
Last State Inspection	Jun 2023
Lead	8 ppb (2021–2023) action level 15 ppb

Violations Reported to EPA

Water Quality	None last 10 years
Treatment and Procedure	None last 10 years
Monitoring and Reporting	None last 3 years

Results are for the whole water system, not water tested at this address; lead at the tap also depends on the building's own pipes.

Internet Providers

Source: FCC Broadband Data Collection, based on 910 locations within half a mile, as of December 31, 2025

Provider	Max Down / Up (Mbps)
Xfinity Cable · Fiber in parts of the area	2,000 / 2,000
Verizon Fixed Wireless	1,000 / 75
T-Mobile Fixed Wireless	100 / 20
AT&T Fixed Wireless	100 / 20

May also be available: Starry.

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