2026 assessment
$879K
OPA value, not a listing price
Property report
1730 Mount Vernon St
3 stories3,375 sqftRM1built 1920
Property at a glanceApartment building
Loonstyn Development LP
2027 published assessment
$826K
Future roll, not the current tax bill
Location
1700 block of Mount Vernon St
ZIP 19130
Neighborhood area
Fairmount · Spring Garden
Approximate · based on ZIP 19130
Assessment and City record timeline
The line tracks this property’s published City assessment. Markers show deeds, permits, inspections, licenses, violations, certifications, and appeals on their recorded dates. Select one to read the filing.
Assessments are tax-roll values, not sale prices or appraisals. OPA has published a 2027 assessment of $825,700. It is not yet the billed-year tax basis.
- OPA assessment · 2016$603K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2017$603K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2018$852K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2019$877K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2020$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2021$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2022$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2023$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2024$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2025$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2026$879K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- OPA assessment · 2027$826K assessed valueOPA’s value on the City tax roll for that year. It is not an appraisal, listing price, sale price, or live tax balance.How Philadelphia property assessments work ↗
- Deed / sale · 2005Deed / sale $9KA recorded real-estate document or transfer event. The amount and date can be useful history, but the underlying deed and transfer-tax filing control the parties, consideration, and legal effect.How to read the recorded document ↗
- Deed / sale · 2015Deed / sale $360KA recorded real-estate document or transfer event. The amount and date can be useful history, but the underlying deed and transfer-tax filing control the parties, consideration, and legal effect.How to read the recorded document ↗
- Permit · 2015-09-30UseThis permit category usually covers the property’s allowed use, dimensions, occupancy, or site configuration. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2015-10-01DemolitionThis permit category usually covers partial or complete removal work. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2015-11-16UseThis permit category usually covers the property’s allowed use, dimensions, occupancy, or site configuration. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2015-11-25Major alterationA broad legacy permit work category for a substantial building alteration. It can include changed layouts, partitions, fixtures, finishes, structural work, or occupancy-related work, but only the approved scope and plans say what this permit actually authorized; separate trade permits may be required.What Philadelphia building permits can cover ↗
- Permit · 2015-11-27AdministrativeThis permit category usually covers construction, repair, alteration, addition, or occupancy work. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2016-03-16ElectricalThis permit category usually covers electrical installation, alteration, replacement, or repair. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2016-03-31MechanicalThis permit category usually covers construction, repair, alteration, addition, or occupancy work. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2016-04-19PlumbingThis permit category usually covers water, drainage, fixtures, or other plumbing work. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2016-04-22PlumbingThis permit category usually covers water, drainage, fixtures, or other plumbing work. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- Permit · 2016-04-28PlumbingThis permit category usually covers water, drainage, fixtures, or other plumbing work. The approved scope—not the short category—defines what was authorized, and issuance alone does not prove completion.Philadelphia construction and repair permits ↗
- License · 2017-05-03William Loonstyn: Rental landlord or residential registration initially issuedA City license record tied to an activity or property use. Its issue, expiration, inactive, and status fields—not the category alone—show what was recorded for this date.Philadelphia L&I licenses and property records ↗
Property assessmentAssessmentDeed / salePermitLicense
Scroll horizontally to move through the years. Each icon sits on its recorded date; records without a day are labeled and centered within their year. Select one to explain the filing.
Highlight
Every dated record13 events · exact dates, newest first
- LicenseWilliam Loonstyn: Rental landlord or residential registration initially issued
- PermitPlumbing
- PermitPlumbing
- PermitPlumbing
- PermitMechanical
- PermitElectrical
- PermitAdministrative
- PermitMajor alteration
- PermitUse
- PermitDemolition
- PermitUse
- Deed / saleDeed / sale $360K
- Deed / saleDeed / sale $9K
Verify the public record
Property tax
$6,992/year estimated property tax
2026 taxable assessment $499,499 × 1.3998%. This is an estimate, not a bill or account balance. The City maintains payments, credits, interest, and the current amount due.
OPA has published a 2027 assessment of $825,700. It is not the 2026 billed-year value.
Payments, credits, interest, and the current amount due are maintained by the City.
OPA 8818075452026 OPA taxes $499,499 of $879,400 assessed. The assessment fields alone do not identify a program, approval date, expiration, or buyer eligibility.
See the assessment math →Historical delinquency sources No current conclusion
This parcel did not match the June 2022 delinquency snapshot. That absence does not confirm the account is current today.
For a purchase, refinance, or closing, request the City’s official Property Payoff statement in Tax Center under “More options.”
Property report
Commercial property
Apartment building, recorded in the City's multi-family category. The public record and owner trail follow.
What it is
Apartment building
Apts 5-50 Units Masonry
Owner
Loonstyn Development LP
$ / sq ft
$245
assessed value ÷ interior sqft
Licensed units
5
active rental license
Interior area
3,375 sqft
Lot size
1,645 sqft
Stories
3
Built
1920
Zoning
RM1
Recorded owner
Who's behind it
Loonstyn Development LP · corporate / LLC owner
• Owns 12 properties across Philadelphia under this name, assessed at $14M combined
• Tax bills mail to 2048 A Fairmount Ave, Philadelphia PA, 19130
• Holds an active rental license for this address
Block context
1700 block of Mount Vernon St. Compare parcels, ownership, and public-record history.
See the whole block →Next door: 1728 Mount Vernon St · 1732 Mount Vernon St
L&I license dates · data through Jul 23, 2026
Business licenses at this address Latest pull
What L&I has registered at this OPA parcel, newest initial license date first.
No L&I business license is on record at this address in data through Jul 23, 2026.
Landlord and residential filings
These are property registrations or landlord filings, not businesses operating at this address.
William LoonstynActive
Rental · Initial issue date May 3, 2017 · Filed expiration May 2, 2027
A license is an L&I registration, not proof that a business is open, operating today, or located at this storefront. Dates are license dates. Events are deduped by parcel, business identity, and license type, so a renewal is not shown as another opening. Other permit and filing types remain in the full source ledger.
Open every source row 13 dated rows
- License issue eventWilliam Loonstyn: Rental landlord or residential registration initially issued
License 737166 · Active
License event. Registration does not prove present operation or storefront occupancy.
- PermitPlumbing
Permit 687940 · COMPLETED
REPLACE SEWER MAIN TO BLDG 5" TRAP, HOUSE DRAIN, FAI S&I 1 1/2" WATER SERVICE PA1# 2016-1171429 "SELF-CERTIFICATION'S ARE NO LONGER PERMITTED" - "ALL EXCAVATIONS AND PLUMBING TRENCHES IN EXCESS OF 5 FEET IN DEPTH MUST HAVE APPROVED SHORING IN PLACE AT THE TIME OF INSPECTION"
- PermitPlumbing
Permit 669317 · COMPLETED
ALTERATION: INTERIOR PLUMBING FOR A 3-STORY, (5) DWELLING BUILDING (MULTI FAMILY). THE INSTALLATION WILL COMPLY WITH THE PHILADELPHIA PLUMBING CODE 2004. A SEPARATE PERMIT IS REQUIRED FOR THE BACKFLOW PREVENTION CONTAINMENT ASSEMBLY.
- PermitPlumbing
Permit 685363 · COMPLETED
INSTALL NEW 1-1/2"RPZ BACKFLOW PREVENTOR (MULTI FAMILY)THE INSTALLATION WILL COMPLY WITH THE PHILADELPHIA PLUMBING CODE 2004
- PermitMechanical
Permit 680772 · COMPLETED
INSTALL (5) HVAC SYSTEMS WITH DUCTWORK. (MULTI-FAMILY)
- PermitElectrical
Permit 669034 · COMPLETED
INSTALL 600AMP SERVICE AND WIRE THROUGHOUT WITH RECEPTS,LIGHTS,FIXTURES,SWITCHES,SMOKES AND CO DETECTORS AS PER 2008 NEC (CC DISTRICT) INSTALL COMPLETE FIRE ALARM SYSTEM THROUGHOUT AS PER NFPA72
- PermitAdministrative
Permit 654707 · COMPLETED
TO AMEND AP#651337 TO REFLECT THE CORRECT BUILDING COST.
- PermitMajor alteration
Permit 651337 · COMPLETED
FOR INTERIOR LEVEL 3 ALTERATIONS TO EXISTING APARTMENT BUILDING (R-2 OCCUPANCY) AS PER PLANS. SEPARATE PERMITS REQUIRED FOR MECHANICAL, ELECTRICAL, PLUMBING AND FIRE SUPPRESSION WORK.
- PermitUse
Permit 643671 · COMPLETED
FOR THE DOCUMENTATION OF EXISTING FIVE UNITS AS PER PERMIT 148227
- PermitDemolition
Permit 642254 · COMPLETED
INTERIOR DEMOLITION NON LOAD BEARING PARTITIONS ONLY, NO CHANGES TO EXTERIOR AND NO WORK ALTERATIONS EXTERIOR WINDOWS AND DOORS PER HISTORICAL COMMISSION APPROVAL(4 FAMILY)
- PermitUse
Permit 641938 · COMPLETED
USE TO (4) FAMILY DWELLING
- Recorded transfer$360K transfer
2015
- Recorded transfer$9K transfer
2005
Where this comes from
- Assessment, spec sheet & owner: OPA Property Assessments, Office of Property Assessment
- Sales & deed history: Realty Transfer Tax records, Recorder of Deeds
- Permits, violations & inspections: L&I Property History · Atlas
- Tax delinquency snapshot · June 2022: Real Estate Tax Delinquencies, Dept. of Revenue
- Historical tax ledger & liens · through 2016: Real Estate Tax Balances, Dept. of Revenue
- Current property-tax balance: Verify with Philadelphia Revenue
- Zoning appeals: L&I & Zoning Board appeals
- Neighborhood income & rents: US Census ACS 5-year estimates
- Historical mortgage rates: Freddie Mac Primary Mortgage Market Survey, annual averages
- Imagery: Street photo © Google · Aerial © Esri, Maxar
Methodology & freshness
This report was assembled Jul 24, 2026, 1:22 AM ET. Available City datasets are queried from OpenDataPhilly (phl.carto.com) and the cited City ArcGIS feeds; record queries paginate rather than silently taking a first page. For this property: Permits: queried · Violations: queried · Investigations: queried · Appeals: queried · Licenses: queried · Building certifications: queried. “Unavailable” means the source query failed or was not supplied, not “no record.” Reports re-pull on view after seven days and on an overnight rolling schedule; citywide benchmarks recompute weekly. Source dates still govern: the parcel-level tax-delinquency snapshot is June 2022 and the separate detailed tax ledger ends in 2016, so neither establishes today’s balance. The live balance and date-effective payoff must be verified in Tax Center. AI-written passages are grounded in the assembled record and rejected if they state a number the record does not hold.
Official city record ↗ · L&I history ↗ · See the whole block · Download this record (JSON)