House report

817 S 51st St

2 stories · 1,350 sqft · RSA3 · built 1925

Owner-occupied · assessed $317K · sold 1×. On the 800 block of S 51st St.

Property summary

Assessment$317KCity assessed value Last sale$67KRecorded 2003 Est. annual tax$3K/yearAssessment × 1.3998% Tax delinquency—Snapshot unavailable Permits8Dated events in report ViolationsNone openNone open when assembled

Report assembled Jul 9, 2026 “Open” reflects records available then historical records keep their source dates estimates are labeled

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Street view of 817 S 51st St — From the street — imagery © Google

From above — imagery © Esri, Maxar

What stands out

From the public record

Finding

Improved

Why it matters

Owner pulled a plumbing permit in 2018.

View supporting records →

Records to verify together

Rule-based groupings across this property's dated public records. Each flag shows the records that belong in the same verification step and where the inference stops.

Dated record flagAssessment/permit mismatch

The assessment jumped 104% in 2023, but no matching permit appears in the property timeline.

Evidence: assessment moved from $141,900 to $289,500 · no permit shown in 2022-2024

Limit: Not proof of unpermitted work; reassessment, corrected data, or a permit under another parcel can also explain it.

Transparent record rules, not a score or forecast. Each flag is a prompt to verify the cited records, not a prediction or allegation.

What to do with this

The record, translated into moves — what a buyer, the owner, and a landlord would each want to check next under Philadelphia's actual rules.

If you’re buying

Built 1925: lead rules apply

Federal law requires a lead-paint disclosure at sale for any pre-1978 home. If it will be rented, Philadelphia also requires a lead-safe or lead-free certificate before a rental license can issue.

Zoned RSA3: one household by right

Single-family attached. Converting to a duplex or apartments needs a use variance the zoning board rarely grants — Pennsylvania courts require a physical hardship of the lot itself, and economics alone do not qualify.

Derived from this house's public records and the city's rules as of 2026 (abatement ordinance, Homestead, rental licensing, lead certification, L&I process, excavation protections). Informational only — not legal, tax, or investment advice.

The investment read

How this house has moved and where it's pointed: the city's assessed value (not a listing price) over 12 years, charted against its block; appreciation is that history's pace, and the 5-year figure simply extends it. Yield estimates rent-vs-price from area rents. Ask the record to dig into any number.

Assessed value

$317K

built 1925

Price / sq ft

$235

block $221 · above block

Appreciation

+198%

+10%/yr, city 6.5%

In 5 years (~2031)

~$319K

+10%/yr own pace held 5 yrs — extrapolation, not a forecast

Est. tax / yr

$3K

0.96% effective

Jun 2022 tax snapshot

—

Gross yield

≈$2K/mo rent

Times sold

Value vs. the block, over time — sales, permits & L&I events marked on the line

This houseBlock median & rangePermit

The paper trail

Improved

Owner pulled a plumbing permit in 2018.

2009 ZoningPermitAdditionPermit
2010 ElectricalPermitPlumbingPermitAppeal city affirmedZoning6 L&I violationsL&IMajor alterationPermitInspection failed ×3L&I visit
2011 Major alterationPermit
2013 Inspection passedL&I visit
2018 PlumbingPermitPlumbingPermit

Flags: 1 zoning/board appeal on record. Informational only — not investment advice or a consumer report (FCRA).

The house, on paper

The city assessor's field record — the physical spec sheet behind the assessed number.

Stories

Interior

1,350 sqft

livable area

Lot

2,320 sqft

Exterior condition

Average

city code 4

Above averageBelow average

Interior condition

Average

city code 4

Above averageBelow average

Quality grade

assessor's grade

ABCDE

Zoning

RSA3

city zoning code

Zoning appeals

city affirmed 2010

OPA field-assessment attributes. Condition and grade are the assessor's codes, not an inspection.

Run the numbers

What owning 817 S 51st St takes, at your price and your rate. Taxes start with an annual estimate from the City’s taxable assessment, not a current bill or balance; rent starts at the area median. Assessed value is not an asking price — set the price slider to the real one.

Purchase price$317K

Down payment20%

Mortgage rate6.875%

Monthly rent$2K/mo

When this house last sold (2003) a 30-year mortgage ran about 5.83% — Freddie Mac's average that year.

Mortgage

—

P&I · 30-yr fixed

All-in monthly

—

+ taxes & insurance

Cash to close

—

down + ~4% costs

Cash flow

—

rent − all costs · /mo

Cap rate

—

NOI ÷ price

Cash-on-cash

—

year-1 return on cash in

Estimates for orientation, not advice. Assumes a 30-year fixed loan, $1,400/yr insurance, 1% of price/yr maintenance; taxes from this parcel's record.

Block context

817 S 51st St sits on the 800 block of S 51st St. Open the block report to compare its parcels, ownership and public-record history.

See the whole block →

Next door: 815 S 51st St · 819 S 51st St

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

Methodology & freshness

Available City datasets are queried from OpenDataPhilly (phl.carto.com), then reports are cached and refreshed on a rolling schedule. Source dates vary: the parcel-level tax-delinquency snapshot is June 2022 and the separate detailed tax ledger ends in 2016, so neither establishes today’s balance. Other dossiers re-pull on view once stale, and citywide benchmarks recompute weekly. AI-written passages are generated from these records only and rejected if they state a number the record doesn't hold.

BlockReport AICited sources

Ask about this property across the connected public record. Curated questions are free; ask 3 custom questions per browser. Analyst includes up to 150 custom questions per day.

About this data & fine print

Answers are generated by an AI agent querying available City of Philadelphia open data at the moment you ask: OPA property assessments, Recorder of Deeds transfer records, L&I permits, violations & licenses, dated Dept. of Revenue tax records, Zoning Board appeals, Police incident reports, Philly311 requests, and School District of Philadelphia catchment and school data.

For an explicit web search or a current listing/news question, the agent may also search the public web through OpenRouter and must link every web-derived claim. Public listing pages can be stale and are not direct or comprehensive MLS access.

Property-level tax data is historical: the delinquency snapshot is dated June 2022 and the separate detailed ledger ends in 2016. Neither shows what is owed today; verify a current balance with Philadelphia Revenue.

City data is published as-is and can lag, contain errors, or be corrected later; school performance datasets run years behind and are labeled with their school year. AI answers can contain mistakes — verify anything that matters against the official record (property.phila.gov, atlas.phila.gov) before acting on it.

Informational only. Not legal, financial, or investment advice. Not a consumer report under the FCRA — it may not be used to decide anyone's eligibility for housing, tenancy, employment, credit, or insurance.

Official city record ↗ · L&I history ↗ · See the whole block · Download this record (JSON)