Neighborhood
Cos Cob
Greenwich, Connecticut US
Cos Cob, Greenwich, Connecticut has a mixed investment profile: pricing is in line with Greenwich and about 285% above Connecticut, while gross yield is 2.2%. Prices are up 13.1% over the past year, which supports recent momentum. The neighborhood has a Red Flag score of 62, walkability of 59, and education in the 97th percentile, combining strong school metrics with a moderate risk reading.
AI Summary•Updated May 2026
Area
1.54 mi²
ZIP Code
06830
County
Western Connecticut Planning Region
State
Connecticut
Redfin — median sale & volumeZillow ZORI — asking rentFEMA National Risk Index v1.20OpenStreetMap — POIFBI UCR — state crimeWashU ACAG — satellite PM2.5EPA FRS / BTS — hazard screeningUS Census ACS / TIGER 2024
Verified Price · Median Sale
$2,574,236
YoY+13.1%
Gross Rental Yield
2.2%
Listed rent · ZORI annualized
Red Flag Index
High
62 / 100
Walkability Score
59
OpenStreetMap POI density · national percentile
Education Score
97 / 100
Pre-pandemic SEDA (2018/19) · district proxy
AI Score
38
DistrictScore attractiveness · national model
Cos Cob Property Prices & Rental Yield
Verified Redfin sale data and Zillow ZORI asking rent for Cos Cob, Greenwich.
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Sign in to view — freeMarket Economics Snapshot
May 2026| Metric | Value | YoY |
|---|---|---|
| Median Sale Price | $2,574,236 | +13.1% |
| Price / Sq Ft (Verified) | $896/sqft | +7.3% |
| Asking Rent (Median) | $4,653/mo | +13.6% |
| Gross Rental Yield | 2.2% | — |
| Liquidity Score | 28 / 100 | Low |
| Homes Sold (Period) | 73 | -30.5% |
Is Cos Cob Safe? Natural-Hazard Risk
FEMA National Risk Index composite across eight hazards, plus inherited Connecticut crime context.
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Sign in to view — free What Stands Out AI Insight
Appreciating market — +13.1% sale-price YoY
Active transaction volume — 73 homes sold last period
Flood risk is Very High (100/100)
Hurricane risk is Very High (100/100)
Insights are generated from Cos Cob's live DistrictScore metrics.
Cos Cob Environment & Safety
Satellite PM2.5 air-quality history, FBI UCR crime trend (Connecticut-level, the finest official aggregation), EPA radon potential and point-source hazard screening.
Air Quality — PM2.5
2015–20247.8 µg/m³ Meets EPA, above WHO guideline+12.1% since 2015
EPA 9WHO 5
20152024
Annual mean fine-particle (PM2.5) concentration at the Cos Cob centroid, satellite-derived (ACAG). References: WHO guideline 5 µg/m³ · EPA annual standard 9 µg/m³. Latest year ranks worse than 94% of U.S. neighborhoods.
Connecticut Crime Trend
FBI UCR20132024
All crimes / 1k
Violent / 1k
| Year | Crimes / 1k | Violent / 1k | YoY |
|---|---|---|---|
| 2024 | 15.0 | 1.4 | -11.7% |
| 2023 | 17.2 | 1.5 | +3.8% |
| 2022 | 16.6 | 1.5 | -1.4% |
| 2021 | 16.9 | 1.7 | -1.6% |
| 2020 | 17.5 | 1.8 | +7.8% |
| 2019 | 16.2 | 1.9 | — |
Reported at the state level — the finest official US crime aggregation; Cos Cob inherits the Connecticut figures.
Environmental Hazards
EPA / BTSIndustrial odor1 nearbyHigh
Point-source screening near Cos Cob: EPA Superfund National Priorities List & Facility Registry (2026), BTS aviation noise (2020, 24-hour average level). Superfund shows distance to the nearest listed site; odor shows detected sources within the screening radius. Only detected sources are listed; the bar shows severity vs. all U.S. neighborhoods.
Walkability & Amenities in Cos Cob
Amenity density and pedestrian access from OpenStreetMap points of interest.
Walkability & Amenities
OpenStreetMap POI59
Somewhat Walkable
Walkability Score
3
Grocery
27
Dining
4
Schools
0
Universities
0
Hospitals
1
Pharmacies
15
Parks
2
Rail Transit
0
Coworking
POI counts are amenities within Cos Cob's boundary plus a 400 m walk buffer. Rail transit excludes bus stops.
Cos Cob vs Greenwich vs Connecticut
How Cos Cob benchmarks against its city and state medians.
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Sign in to view — freeBuying Property in the US as a Foreigner
Federal & Connecticut tax facts for non-resident buyers, plus the latest local market news.
Buying as a Foreigner
US Tax & OwnershipApplies to everyone7
Capital Gains (Federal)
Long-term capital gains taxed federally at 0/15/20%, plus a 3.8% Net Investment Income Tax on higher incomes (2026).
Property Tax
Property tax: ~1.36% average effective rate (statewide average; set and collected locally).
State Income Tax
State income tax up to 6.99%; rental income is taxed at these rates.
State Capital Gains
Capital gains are taxed as ordinary income at state rates.
Transfer Tax
Real estate transfer tax: graduated, with a high-value surcharge over $2.5M.
Assessment Cap
No Proposition 13-style assessment cap; property is reassessed at market value.
Mansion Tax / Rent Control
Mansion-style surcharge: an extra 2.25% on the price portion above $2.5M.
US citizens & tax residents7
Primary-Home Exclusion
Selling your main home: exclude up to $250k of gain (single) / $500k (married) if you owned and lived there 2 of the last 5 years.
1031 Like-Kind Exchange
A 1031 like-kind exchange defers capital gains tax on investment property; 45 days to identify, 180 to close. Real estate only.
Depreciation Recapture
Residential rentals depreciate over 27.5 years; on sale, recaptured depreciation is taxed up to 25% (Section 1250).
Mortgage Interest Deduction
Mortgage interest is deductible on up to $750k of home debt. The SALT cap rose to $40,000 for 2025-2029 (reverts to $10k in 2030).
Opportunity Zones
Opportunity Zones are now permanent (2025): reinvested capital gains get deferral plus a basis step-up, and are tax-free after 10 years.
Rental Income (Resident)
Rental income is reported on Schedule E; passive-loss rules (Section 469) limit deducting rental losses against other income.
1031 State Conformity
The state conforms to the federal 1031 like-kind exchange rules.
Foreign buyers (non-residents)5
FIRPTA (Foreign Sellers)
FIRPTA: the buyer withholds 15% of the gross sale price when a nonresident sells US property. It is an advance deposit, not the final tax.
Non-Resident Capital Gains
Nonresident sellers pay US capital gains tax (generally 15-20%) on the net gain via Form 1040-NR; FIRPTA withholding is credited.
Non-Resident Rental Tax
Nonresident rental income is taxed at 30% of gross by default, or on net income at graduated rates via a Section 871(d) election (W-8ECI).
Estate Tax (Non-Resident)
Nonresidents get only a $60,000 US estate-tax exemption (vs $13.99M for residents); US property above it is taxed up to 40%. Treaties may help.
ITIN Requirement
Nonresidents without an SSN need an ITIN (Form W-7) to file US tax returns, claim FIRPTA refunds, and report rental income.
Talk to a US real-estate tax advisor
FIRPTA, ITIN & Connecticut property-tax guidance for foreign buyers
Cos Cob Real Estate FAQ
Cos Cob, Greenwich, Connecticut shows a mixed profile. Gross yield is 2.2%, prices are in line with Greenwich and about 285% above Connecticut, and values are up 13.1% over the past year. The Red Flag score is 62, with walkability of 59 and education in the 97th percentile.
Neighborhoods near Cos Cob
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