18 Saint Joseph Ave · Lake Ronkonkoma, NY 11779

$559,000

4 bd · 3.5 ba · 1,885 sqft · SingleFamily public records · 10 Days on market

Built 1955 6,098 sqft lot Est $690k · 19% under

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Why this score? — see what drove the D+ grade

The composite is a weighted blend of 9 inputs, each scored 0–100. Each bar is that input's sub-score; the figure is the points it added to the 100-point composite (weight × sub-score).

• ARV discount +15.0/15.0
• Cash flow +10.9/30.0
• Schools +6.6/10.0
• Livability +3.9/5.0
• DSCR +3.2/10.0
• 1% rule +3.0/10.0
• Rent growth +2.7/5.0
• Condition / age +2.5/5.0
• Appreciation +0.0/10.0

Listing remarks

This unique, spacious four-bedroom, three-and-a-half-bath home in Ronkonkoma offers ample space for an extended family. Boasting a newer roof, a full-house generator, Entire HVAC system 2 years old, Hot water heater and split unit 2 years old, 2 driveways and central air conditioning, the home also features two separate hot water systems. Hardwood floors exist just waiting to be brought back to life. Tons of outdoor storage. Additional highlights include super low taxes and a prime location close to the Long Island Railroad, shopping, and dining. This well-maintained property is ready to welcome you.

Key facts

• Two driveways
• Newer roof
• Full-house generator

Tags

• NEWER ROOF
• FULL-HOUSE GENERATOR
• TWO DRIVEWAYS
• CENTRAL AIR CONDITIONING
• TWO SEPARATE HOT WATER SYSTEMS
• HARDWOOD FLOORS

Property features AI

Exterior

• Parking: Driveway
• Utilities: Cesspool sewer; Cable available
• Home design: Single family residence
• Construction: Frame construction
• Exterior features: Frame construction; Not waterfront

Interior

• Kitchen: Gas oven
• Bedrooms: Bedroom on the first floor
• Bathrooms: 3 full bathrooms; 1 half bathroom
• Heating & cooling: Central air conditioning; Natural gas heating
• Interior features: First-floor bedroom; First-floor full bathroom; Partial attic; 10 total rooms

What this means for you Summary

Snapshot

• This is a 4-bed/3.5-bath single-family listed at $559k.

Deal economics

• At list price, monthly cash flow is $-241 ($-3k/yr) — negative.
• To cash-flow at today's rent, offer at most $516k (7.6% below list).
• To meet the 1% rule (rent ≥ 1% of price), the offer needs to be $448k (19.9% below list).
• Recommended offer: $448k (19.9% below list) — sets the bar for 1% rule.
• Cap rate 5.8% vs local median 4.0% in Lake Ronkonkoma — top-decile yield for the area; either an underpriced asset or a hidden risk that comps aren't pricing in. Stress-test before assuming the spread holds.

Location & tenants

• Location reads 78/100 on livability (#169 in NY, #2,606 nationally) — a middle-class / working-renter tenant base. Strengths: employment A+, housing A+, health & safety B; Watch: amenities D-, cost of living F.
• Sachem Central School District (suburban): math 69% / reading 76% proficiency, ranked #86 of 590 in NY (top 15%) — strong family-tenant draw, lease renewals of 3-5y typical; only 15% free/reduced lunch — higher-income household profile.
• Zoned schools: Chippewa Elementary School (math 47% / reading 62%, grade C, #908 of 2,108 statewide, top 46%, 515 students, 25% FRL); Samoset Middle School (math 51% / reading 63%, grade B, #192 of 729 statewide, top 28%, 892 students, 31% FRL); Sachem High School North (math 96% / reading 95%, grade A+, #76 of 1,100 statewide, top 7%, 1,923 students, 25% FRL).
• Market conditions: Rents flat; 175 active listings in the ZIP; 3 comparable units currently listed for rent nearby; rentals at typical pace (median 26d on market — plan ~3-4 weeks tenant-placement turnaround); high-income renter base; 1,366 units permitted in Suffolk County in 2024 (216 in 5+ unit buildings).
• At $4,477/mo this rent would consume 48% of the median local household income ($112k/yr) (locally 874% of renters already pay >50% of income on rent) — very limited rent-growth headroom before tenants either downsize or default.

Forward outlook

• Local home prices are declining (-3.0%/yr); year-one equity from $4k of loan paydown is wiped out by about $17k of value loss. Plan a longer hold.
• Suffolk County population projected to shrink 5% by 2050 — rents likely to lag national; underwrite the cash flow, not the appreciation.

Negotiation context

• Only 10 days on market — expect competitive offers; lowballing is unlikely to land.

Risks & watch-outs

• Watch-outs: built in 1955 — expect roof / HVAC / electrical / plumbing capex.
• Climate carrying-cost: major wind risk, 73% chance of damaging wind over 30y; extreme-heat days projected 7→17/yr by 2055 (HVAC capex compounding) — expect insurance premiums to compound above CPI over the hold.

Recommended offer $447,709 (19.9% below list)

Questions for the listing agent

1. What do current leases actually rent for vs. the listed asking? Can we see a recent rent roll and the last 12 months of T-12 income?
2. Built in 1955 — when were the roof, HVAC, electrical panel, plumbing, and water heater last replaced?
3. Is there a deadline driving the sale (1031 exchange, divorce, estate, relocation)? That informs how much negotiation room exists.
4. Schools are B-rated — typically a magnet for longer-tenancy family renters. What's the average tenant stay here, and is there a school-zone premium baked into asking?
5. The area grade is low — what's the realistic commute time and amenity access for the typical tenant pool here? Any planned neighborhood developments (good or bad) we should know about?
6. What's the average days-on-market for RENTAL listings here right now (not sales)? A rising rental-DOM trend means longer vacancies and softer asking-rent achievability than the comps imply.
7. What's the recent tenant-quality profile in this submarket — average credit score on applications, eviction rate, late-payment / NSF rate, and stable-employment percentage? A property-management company in the area should have these aggregated.
8. How much new for-sale + rental construction is in the pipeline within 1–3 miles? Heavy new supply typically softens prices + rents 12–24 months out; constrained supply supports both.

Investment metrics

• 1% rule: 0.80% ✗
• Cap rate: 5.78%
• Cash-on-cash: -1.85%
• DSCR: 0.92
• GRM: 10.4

CMA / ARV

• ARV (on-the-fly): $689,910
• Comps found: 12

Show comp detail 12 sales within ~0.75 mi

Address	Dist	Beds/Ba	Sqft	Sold	Price	$/sf	Match
327 Ronkonkoma Ave	0.24mi	4/3.0	2,000 (+6%)	12mo	$999,950	$500	66
12 Wyant Ave	0.21mi	4/2.0	1,988 (+6%)	11mo	$615,000	$309	66
22 10th St	0.19mi	3/2.0 (-1)	1,800 (-4%)	11mo	$685,000	$381	64
47 2nd St	0.49mi	3/2.0 (-1)	1,858 (-1%)	0mo	$650,000	$350	64
N/C Caroll Ave	0.30mi	5/3.0 (+1)	2,020 (+7%)	7mo	$800,000	$396	62
12 Bay Ave	0.27mi	4/2.0	1,728 (-8%)	9mo	$610,000	$353	60
30 Lake Promenade	0.35mi	3/2.0 (-1)	1,954 (+4%)	10mo	$715,000	$366	58
45 Marc St	0.58mi	4/2.5	2,039 (+8%)	12mo	$720,000	$353	46
106 Bay Ave	0.52mi	4/2.0	2,132 (+13%)	10mo	$685,000	$321	39
37 Weichers Ave	0.63mi	3/2.0 (-1)	1,666 (-12%)	3mo	$695,000	$417	38
8 Adolphi Pl	0.58mi	3/2.0 (-1)	2,102 (+12%)	6mo	$555,000	$264	37
14 Emily Dr	0.72mi	3/2.0 (-1)	1,604 (-15%)	12mo	$620,000	$387	20

Match score weights: distance 35% · size 25% · config 20% · recency 20%. Top-matched comps best support the ARV.

Projected returns pro-forma

-3.0% appreciation · 0.79% rent growth · sell at horizon

5-year hold

• IRR: -21.8%
• Equity multiple: 0.26×
• Total profit: $-115,640
• Equity at exit: $83,349

10-year hold

• IRR: -21.8%
• Equity multiple: -0.01×
• Total profit: $-158,618
• Equity at exit: $48,332

Cash invested: $156,520 (down + closing). Projections, not guarantees.

Landlord ↔ Tenant lean methodology

• Overall (STATE): 15 Strongly Tenant-Friendly
• State New York: 15 Strongly Tenant-Friendly · D+10
• County: — inherits STATE
• City: — inherits STATE

NYC rent stabilization (~1M units); 2019 HSTPA strengthened tenant rights; courts deeply backlogged.

Methodology + full state rankings →

ZIP-level market 11779

• Rents YoY: 0.8%
• Active inventory: 175
• Price-to-rent: 10.4×

Monthly cashflow live

• Estimated rent: $4,477 medium
• Mortgage (P&I): −$2,931
• Tax from tax record: −$613 /mo · $7,359/yr
• Insurance: −$233
• HOA: −$0
• Vacancy / Maint / Mgmt: −$940
• Net cashflow: $-241

Break-even live

Break-even rent $4,782

Max offer price $516,474

Occupancy floor —

Sensitivity live

Price	-10% $76	-5% $-83	+0% $-241	+5% $-399	+10% $-557
Rent	-10% $-594	-5% $-418	+0% $-241	+5% $-64	+10% $113
Rate	-1.0pp $41	-0.5pp $-99	base $-241	+0.5pp $-386	+1.0pp $-533

UW: 25.0% down · 7.5% · 30yr · 1.5% tax · 5.0% vac · 8.0% maint · 8.0% mgmt

Financing live

Cash to close

• Down payment: $139,750
• Closing costs: $16,770
• Reserves months: —
• Total cash needed: —

Rent comps 3 comps

Address	Beds	Baths	Sqft	Rent	$/sqft	DOM	Units	Dist
2 Hawkins Ave Lake Ronkonkoma, NY	3.0	1.0–2.0	959	$5,009	$5.22	0d	130	0.47mi
100 Lake Rd Ronkonkoma, NY	3.0	2.5	1800	$4,500	$2.50	45d	1	0.61mi
16 Birch Dr Ronkonkoma, NY	3.0	2.0	1536	$4,250	$2.77	26d	1	0.66mi

Listing history 2 events

1. 2026-04-15
   status Pending
2. 2026-03-31
   listed $559,000 Active

ⓘ Source: listings_history table (triggers on properties + properties_extension) + one-shot backfill from property_details.listing_events for pre-trigger history.

Tax reassessment forecast NY · Partial reset (capped growth)

• Current annual tax: $7,359 · $613/mo
• Projected year-2 tax: $8,403 · $700/mo
• Expected delta: +$1,044/yr (+$87/mo · 14.2%)

ⓘ Screening estimate from a state-policy table — verify with the county assessor before closing.

Climate risk First Street

• 🌊 Flood 1/10 Low FEMA zone X (unshaded) · 0% chance over 30 yrs
• 🔥 Wildfire 1/10 Low
• 🌡 Heat 5/10 Major 7 d/yr ≥93°F today · 17 d/yr by 30 yrs out
• 💨 Wind 6/10 Major 73% chance of damaging wind over 30 yrs
• 🫁 Air quality 4/10 Moderate 4 unhealthy d/yr today · 6 by 30 yrs out

Taxation est. · year 1

• Rental income: $53,725
• − Mortgage interest: −$31,313
• − Property taxes: −$7,359
• − Insurance: −$2,795
• − Repairs & maintenance: −$4,298
• − Management: −$4,298
• − Depreciation: −$16,262
• Taxable loss: −$12,600
• Est. tax savings @ 24.0%: +$3,024
• After-tax cash flow: $135/yr

For passive investors: Depreciation is non-cash, so a rental often shows a tax loss while cash-flowing — sheltering income. Rental losses are passive: they offset passive income freely, and up to $25,000/yr can offset ordinary (W-2) income if you actively participate and your MAGI is under $100k (phasing out to $0 by $150k); unused losses carry forward. On sale, claimed depreciation is recaptured at up to 25%, and gains may owe capital-gains tax (a 1031 exchange can defer both). Figures are a year-1 estimate at your 24.0% rate — not tax advice; consult a CPA.

Schools (NCES district)

• District: Sachem Central School District
• NCES district ID: 3625350
• Math proficiency: 69% ▬ 0.00%
• Reading proficiency: 76% ▲ 12.00%
• Median HH income: $92,968
• Composite: 65.53/100
• National rank: #472
• State rank: #86 of 590 in NY

Livability — Lake Ronkonkoma

• Score: 78/100
• State rank: #169
• US rank: #2606

Category grades

Amenities D- Commute B- Cost of living F Crime C+ Employment A+ Housing A+ Health & safety B User ratings A+

Schools grade is shown separately in the Schools card above.

Census & demographics

• Census place: Lake Ronkonkoma, NY
• County: Suffolk County · 679,920 people
• City population: 38,273
• Metro: New York-Newark-Jersey City, NY-NJ-PA
• Population (ZIP): 38,206
• Household income: $112,180
• Rent vs Own: 24.3% rent · 75.7% own
• Severe rent burden: 874.0

Population outlook (Suffolk County) Hauer SSP2

• Today (2025): 1,505,262 people
• By 2030: 1,498,318 · -0.5%
• By 2040: 1,471,101 · -2.3%
• By 2050: 1,424,848 · -5.3%
• By 2075: 1,337,157 · -11.2%
• By 2100: 1,217,720 · -19.1%

Race, ethnicity, and origin ACS 2023

• Neighborhood character: Predominantly White (67%)
• Race & ethnicity: White 67% Hispanic / Latino 19% Two or more races 9% Asian 7% Black 5%
• Hispanic origin (detail): Puerto Rican 7% Dominican 1%
• Common ancestry: Romanian 4% Scotch-Irish 1% Lithuanian 1%
• Foreign-born: 14% · Canada, Jamaica, China
• Languages at home: 79% English-only · Spanish 10% Other Indo-European 7% Other Asian/Pacific 1%

Political lean MEDSL · Suffolk

• 2024 margin: Lean R (+10.0) · D 45.0% · R 55.0%
• 2008→2024 swing: -16.0pp toward R · 2008: 6.0pp · 2024: -10.0pp
• All cycles: 2024: R+10.0 2020: R+0.0 2016: R+8.2 2012: D+2.9 2008: D+6.0

Not yet ingested

• Civics: —

Market trends

• HPI YoY: ▼ -569.98%
• Current HPI: 350.0973
• Rent YoY: ▲ 0.79%
• Metro: New York-Newark-Jersey City, NY-NJ-PA
• State GDP YoY: ▲ 2.60%
• F500 in state: 92

Industry mix (Fortune 500 HQ in NY)

Industry	F500 HQs	Revenue
▸Financial Services	10	$950B
▸Consumer Goods	9	$162B
▸Insurance	4	$225B
▸Telecommunications	2	$144B
▸Pharmaceuticals	2	$112B
▸Media / Entertainment	2	$69B

Price history

2 events — show timeline

• 2026-04-15 Pending — OneKey® MLS as Distributed by MLS Grid
• 2026-03-31 Listed $559,000 OneKey® MLS as Distributed by MLS Grid

Property tax history

+2.7%/yr

Latest (2025): $7,359 · +0.0% YoY. Source: county tax records.