ACS 2021 release
2017-2021 five-year estimate
- Median home value B25077
- $388,600Margin of error ±$131,136
- Median gross rent B25064
- $871Margin of error ±$303
- Population B01003
- 1,162Margin of error ±170
Rental market · ZIP 04421 · Castine, ME
ZIP 04421, Castine, ME rental market
Population 1,362 · Castine, Hancock County, ME · ZIP Code Tabulation Area
Ranked · ACS 2024 5-year
DGRADE
34.5/100 · Rental Investor ZIP Score
National rank #14,929 of 20,132 scored ZIP Codes
ME rank #186 of 228 · data confidence: moderate
under 28.1DCBA
Grade cut points, score out of 100: A from 63.7 · B from 54.7 · C from 42.4 · D from 28.1. This ZIP's 34.5 sits in the D band, which opens at 28.1 and ends below 42.4. The cut points are the model's own, read from the published ZIP dataset, and are identical for every ZIP Code area.
The four category scores that combine into the number above, on the model's own 0 to 100 score scale. These bars are not percentiles: for where those scores place this ZIP Code against every other scored one, see how this ZIP ranks below.
Cash Flow & Affordability ZIP data
22
Local Demand & Market Quality ZIP data
36
Surrounding-Market Growth county / place context
66
Stability & Risk ZIP + place context
37
Why it ranks here: the surrounding county/place is growing.
Watch: cash flow is thin relative to price. elevated stability/risk signals. survey margins of error are wider here (data confidence: moderate).
Scored on incomplete measured inputs: this ZIP is missing measured 3-yr home-value growth (Zillow), a measured home value (Zillow) to substitute into affordability/tax-burden, so it was scored on a narrower input basis than a ZIP with full measured coverage.
A transparent screening score, not a return forecast. Affordable, higher-yield markets can score well when demand, liquidity, low vacancy, reliable government data and a growing surrounding market support them. Categories labeled “context” use official county/place data, never presented as ZIP-level observation. ZIP and city scores are not directly comparable. See how this score works.
How this ZIP ranks: nationally & in-state
Each bar places this ZIP against all 20,132 scored ZIP Codes nationally.Each bar places this ZIP against the 228 scored ZIP Codes in ME. The marker is this ZIP and further right is more favorable to an investor; the tick is the median. Every position here is a percentile: the 0–100 scores and the grade they earn are stated once, in the card above, and this card states once where those same five numbers place this ZIP Code.
Overall Rental Investor ZIP Score
26th percentile
Cash Flow & Affordability
3rd percentile
Local Demand & Market Quality
22nd percentile
Surrounding-Market Growth county / place context
68th percentile
Stability & Risk ZIP + place context
28th percentile
← 0th percentile50th (median)100th percentile →
Percentiles are the frozen model's own numbers among scored ZIP Codes (deterministic competition ranking); an unreliable or thin-peer in-state comparison reads “Not available,” never zero. All underlying figures are ACS survey estimates with margins of error. The comparability caveat and the method link for this score are stated once, in the card above.
What went into this score: 13 national factor percentiles
Cash Flow & Affordability
Gross rental yieldZIP observation
3rd
Price to incomeZIP observation
22nd
Property-tax burdenZIP observation
60th
Rent as a share of incomeZIP observation
3rd
Local Demand & Market Quality
Population scaleZIP observation · scale, not quality
11th
Renter-household depthZIP observation · scale, not quality
14th
Renter share of householdsZIP observation
35th
Rental vacancyZIP observation
86th
Market heat (Zillow measured)ZIP observation
33rd
Surrounding-Market Growth
County population growthcounty context
66th
Stability & Risk
Median year builtZIP observation
40th
ACS data confidenceZIP observation
32nd
Recently built shareZIP observation
40th
Every figure here is the frozen model’s own national percentile for one factor, read from the published ZIP dataset: 13 of the 15 factors this model defines were available for this ZIP Code. 2 of them could not be measured here (surrounding-market growth, surrounding-market stability) and were left out of the average rather than filled in with a national guess. Higher is the direction the model treats as more favourable to a rental investor; population scale and renter-household depth are size, not quality. Each category score is the plain average of its own percentiles above; the overall score combines those four at the weights shown. The percentiles are published rounded to whole numbers, so averaging the printed figures lands a fraction of a point from the published score. This ZIP’s weakest category is 22, below the model’s published floor of 30, so the model applies its floor penalty and the overall score is lower than those four weighted together would be on their own. Nothing on this panel is recomputed here, and a factor percentile is not a score.
Key metrics
1,362
Population
±170 ±12.3% moderate
$603,500
Median home value (ACS, owner-reported)
±$110,000 ±18.9% moderate
$1,105
Median gross rent (ACS, incl. utilities)
±$100 ±9.4% tight
2.2%
Survey gross-rent yield (proxy)
Derived from ACS estimates: no published margin of error
$113,750
Median household income
±$26,000 ±23% moderate
0.0%
Rental vacancy
Derived from ACS estimates: no published margin of error
19.6%
Renter share
Derived from ACS estimates: no published margin of error
0.7%
Estimated property-tax burden
Derived from ACS estimates: no published margin of error
1974
Median year built
±8 years margin in years; a share of a year number would not mean anything
6.9%
Multifamily (5+ units)
Derived from ACS estimates: no published margin of error
Market context
Trend context
Loading home value context…
View source data
Each point is one ACS 5-year estimate on the same 2020-Census ZCTA boundary. Adjacent releases overlap, so the release-to-release differences are not independent annual market movement.
| Series | 2017–2021 | 2018–2022 | 2019–2023 | 2020–2024 |
|---|---|---|---|---|
| Median home value B25077 | $388,600 ±$131,136 | $413,300 ±$138,025 | $557,700 ±$104,098 | $603,500 ±$114,039 |
| Median gross rent B25064 | $871 ±$303 | $992 ±$244 | $1,028 ±$254 | $1,105 ±$104 |
| Population B01003 | 1,162 ±170 | 1,289 ±156 | 1,222 ±139 | 1,362 ±167 |
ACS 2022 release
2018-2022 five-year estimate
- Median home value B25077
- $413,300Margin of error ±$138,025
- Median gross rent B25064
- $992Margin of error ±$244
- Population B01003
- 1,289Margin of error ±156
ACS 2023 release
2019-2023 five-year estimate
- Median home value B25077
- $557,700Margin of error ±$104,098
- Median gross rent B25064
- $1,028Margin of error ±$254
- Population B01003
- 1,222Margin of error ±139
ACS 2024 release
2020-2024 five-year estimate
- Median home value B25077
- $603,500Margin of error ±$114,039
- Median gross rent B25064
- $1,105Margin of error ±$104
- Population B01003
- 1,362Margin of error ±167
Source: U.S. Census Bureau, American Community Survey 5-year, table-based Summary File (ZCTA geography); tables B25077 (median value), B25064 (median gross rent), and B01003 (population); estimate + margin of error. Missing releases remain gaps and are never interpolated. Home value is owner-reported; gross rent describes renter housing stock; population is a ZCTA estimate. Dollar figures are nominal.
Measured market data
Measured observations for this ZIP Code, published beside the government survey figures above rather than replacing them. They measure different things and will legitimately disagree; the reconciliation below states on which axis, one axis at a time, instead of leaving a reader to guess. ZORI does not correct the ACS rent; neither is a better version of the other. Monthly series, revised in recent months, observed 2026-07, not live.
| Market heat index | 44 |
|---|---|
| For-sale inventory | 5 |
Source: Zillow Economic Research public research data, observation month 2026-07. Zillow keys on USPS ZIP codes; this page is a 2020 Census ZCTA, related but not identical geographies, so a Zillow value is matched to this ZCTA by code and is not a statement that the two areas are the same. Zillow is not affiliated with, and does not endorse, Compounding Estates.
Market Negotiation Leverage
Some buyer leverage (67th percentile among scored ZIP Codes)
Derived from Zillow's market-heat index for this ZIP, inverted (a cooler market means more room for a buyer to negotiate). 5 active listings. This is a cross-sectional snapshot (how this ZIP compares to every other tracked ZIP today), not a seasonal or historical baseline for this specific ZIP (no multi-year time series exists to support that claim). Not a prediction of what any specific seller will accept. See how this is calculated.
Source: Zillow Economic Research public research data. Zillow is not affiliated with, and does not endorse, Compounding Estates.
Underwrite with these as starting points
Opening a calculator pre-loads the ACS median owner value and median gross rent as a survey-level starting point; every calculator input is editable. Owner-occupied median value and renter median gross rent describe different housing stock: the median-valued home is not the typical rental, so this is a screen, not a listing, appraisal, asking rent, cap rate, or forecast. Bring your own entry price and rent.
ZIP Codes bordering 04421
6 ZIP Code areas share a land boundary with 04421 in the official Census 2020 ZCTA map, ordered by shared-boundary length, not ZIP-number proximity or driving distance. 4 of them are in CE’s ranked set and are listed below, each with its own Rental Investor ZIP Score, grade and national rank, read from the same published dataset as this page. The rest are counted here and searchable from the ZIP Code explorer. A neighbour’s score is a score for that area, never for 04421, and this list is ordered by border length, so it is not a ranking and no neighbour is called best.
Evidence, sources & limitations
Official geography: Castine CDP, Hancock County. Analytical entity: the U.S. Census ZIP Code Tabulation Area (ZCTA) 04421, an approximation of the USPS ZIP delivery area, not its exact route boundaries. Model z3-measured-v1; data ACS 2024 5-year.
This ZIP Code area is primarily in Hancock County, overlapping Castine, by land-area overlap from the official Census 2020 ZCTA relationship files (not population or address share).
| Population | survey ACS B01003 · ±12.3% margin of error |
|---|---|
| Median home value (ACS, owner-reported) | survey ACS B25077 · ±18.9% margin of error |
| Median gross rent (ACS, incl. utilities) | survey ACS B25064 · ±9.4% margin of error |
| Survey gross-rent yield (proxy) | derived 12 * ACS B25064 / B25077 · no published margin of error |
| Median household income | survey ACS B19013 · ±23% margin of error |
| Rental vacancy | derived ACS B25004 E002 / (B25003 E003 + B25004 E002) · no published margin of error |
| Renter share | derived ACS B25003 E003/E001 · no published margin of error |
| Estimated property-tax burden | derived ACS B25103 / B25077 · no published margin of error |
| Median year built | survey ACS B25035 · ±<1% margin of error |
| Multifamily (5+ units) | derived ACS B25024 (5+ unit structures / total) · no published margin of error |
Class: survey = ACS estimate (with margin of error); derived = computed from ACS. The survey gross-rent yield is a proxy (renter gross rent vs owner-occupied value, different housing stock; ACS top-codes very high values/rents) and is not a cap rate. Subscores are national percentiles among data-eligible areas; ranks are competition-ranked with deterministic ties. No vendor, listing, parcel, or school data. Not investment advice.