Bay Farm Island, Alameda vs Rockridge, Oakland
Bay Farm Island, Alameda carries an effective property tax rate of 1.22% of assessed value and Rockridge, Oakland carries 1.36%, both for fiscal year 2025-26. On one identical reference loan the monthly carrying costs are $9,917 and $10,104 — $187 apart, with Bay Farm Island, Alameda lower. To Oakland City Center at AM peak the fastest published commutes are 20 min by car from Bay Farm Island, Alameda and 12 min by BART from Rockridge, Oakland. Every figure is an objective public metric or arithmetic on one, and names its source.
Bay Farm Island, Alameda (Alameda County) · Rockridge, Oakland (Alameda County)
| Metric | Bay Farm Island, Alameda | Rockridge, Oakland | Difference |
|---|---|---|---|
| Median $/sqft (SFR) | $750 | $1,000 | −$250 |
| Effective tax rate | 1.22% | 1.36% | −0.140% |
| Monthly cost, reference loan | $9,917 | $10,104 | −$187 |
| FiDi SF (Montgomery St BART) — BART | 45 min | 25 min | +20 min |
| FiDi SF (Montgomery St BART) — Drive | 40 min | 35 min | +5 min |
| Oakland City Center (12th St BART) — BART | 35 min | 12 min | +23 min |
| Oakland City Center (12th St BART) — Drive | 20 min | 15 min | +5 min |
| Sunnyvale / Mountain View (Sunnyvale Caltrain) — Drive | 55 min | 70 min | −15 min |
Difference is Bay Farm Island, Alameda minus Rockridge, Oakland. Sources are cited on each submarket page.
Rockridge carries $250 more per square foot than Alameda (Bay Farm) — 33% — and that single spread decides most searches that start with both names on the list. The tax rates land 1.22% in Alameda (Bay Farm) against 1.36% in Rockridge, a 0.14% spread that has to be carried on top of the price difference.
What the same money buys
Rockridge comps run $900-$1,000 per square foot; Upper Rockridge runs $1,000-$1,150. Against that, under $1M on Bay Farm means a townhome or the older tracts west of Island Drive. The median foot costs $750 in Alameda (Bay Farm) against $1,000 in Rockridge; on a 2,000 sq ft house that is $500,000 of purchase price.
Carrying $1,600,000 in each
Against an identical $1,600,000 note at 6.5% with 20% down and $2,400 a year of coverage, Alameda (Bay Farm) totals $9,917 a month at 1.22% and Rockridge $10,104 at 1.36% — tax lines of $1,627 and $1,813. The Bay Farm lagoon villages carry extra lagoon maintenance on top of base dues. Oakland library, parks, paramedic and school parcel taxes stack $800-$1,500 a year on a Rockridge parcel.
Commute, measured
To Sunnyvale / Mountain View (Sunnyvale Caltrain): 55 minutes by driving from Alameda (Bay Farm), 70 by driving from Rockridge — a 15-minute edge to Alameda (Bay Farm), or 2.5 hours across a ten-trip week. To FiDi SF (Montgomery St BART): 35 minutes by ferry from Alameda (Bay Farm), 25 by BART from Rockridge — a 10-minute edge to Rockridge, or 1.7 hours across a ten-trip week. The Harbor Bay terminal is a five-minute drive or ten-minute bike from most of the island. Door to door from the Rockridge bungalows to FiDi is 25-35 minutes, the shortest rail commute in this set.
Fire, flood and the premium
Bay Farm Island is not wildland-urban interface. The Hayward Fault runs along the Rockridge hill base, and the bungalows carry brick foundation and knob-and-tube disclosures. Verify any parcel against the CAL FIRE Fire Hazard Severity Zone map, the FEMA Flood Map Service Center and the California Geological Survey seismic hazard zones before removing contingencies.
The housing need each answers
Bay Farm fits a need for a detached home with a garage inside the ferry catchment. Rockridge is the answer when commute length is the binding constraint.
Sources. Effective rates and carrying costs: Alameda County Tax Rates by TRA FY 2025-26, composited in build/assets/metrics.json; TRA-level verification pending, so confirm the rate on the parcel's own bill. Commute times: door-to-door AM-peak estimates, data/commute/static.csv. Median price per foot is a trailing figure, not a valuation, and the local detail comes from the broker's own transactions.
Compare any two submarkets
| Metric | Bay Farm Island, Alameda | Rockridge, Oakland |
|---|---|---|
| Median $/sqft (SFR) | $750 | $1,000 |
| Effective tax rate | 1.22% | 1.36% |
| Monthly cost, reference loan | $9,917 | $10,104 |
| Fastest to FiDi SF (Montgomery St BART) | 35 min | 25 min |
| Fastest to Oakland City Center (12th St BART) | 20 min | 12 min |
| Fastest to Sunnyvale / Mountain View (Sunnyvale Caltrain) | 55 min | 70 min |
Same reference loan on both sides; the tax line is the only variable. Commute figures are door-to-door AM-peak estimates. Sources are listed on each submarket page.
Bay Farm Island, Alameda detail
| Component | Rate of assessed value |
|---|---|
| Prop 13 general levy | 1.000% |
| County / city voter-approved bonds | 0.042% |
| School district measures | 0.178% |
| Effective rate | 1.22% |
| Mello-Roos / CFD | None recorded |
Source: Alameda County Tax Rates by TRA FY 2025-26 (Alameda County), composited in
build/assets/metrics.json.
Tax Rate Area not yet verified parcel-by-parcel — confirm the rate on the parcel’s own tax bill.
Rockridge, Oakland detail
| Component | Rate of assessed value |
|---|---|
| Prop 13 general levy | 1.000% |
| County / city voter-approved bonds | 0.152% |
| School district measures | 0.208% |
| Effective rate | 1.36% |
| Mello-Roos / CFD | None recorded |
Source: Alameda County Tax Rates by TRA FY 2025-26 (Alameda County), composited in
build/assets/metrics.json.
Tax Rate Area not yet verified parcel-by-parcel — confirm the rate on the parcel’s own tax bill.
Bay Farm Island, Alameda vs Rockridge, Oakland: questions and answers
- Which has the lower effective property tax rate, Bay Farm Island, Alameda or Rockridge, Oakland?
- Bay Farm Island, Alameda, at 1.22% of assessed value against 1.36% for fiscal year 2025-26 — a gap of 0.140%. Rates are composited from county tax rate books; each parcel bill governs.
- How much do monthly carrying costs differ between Bay Farm Island, Alameda and Rockridge, Oakland?
- $187 per month on the identical reference loan: Bay Farm Island, Alameda $9,917, Rockridge, Oakland $10,104. Bay Farm Island, Alameda is lower. Principal and interest are held constant, so the difference is the tax line. Arithmetic only.
- Which has the shorter commute to Oakland City Center, Bay Farm Island, Alameda or Rockridge, Oakland?
- Rockridge, Oakland. Bay Farm Island, Alameda is 20 min by car; Rockridge, Oakland is 12 min by BART. Door-to-door, AM peak. Source: data/commute/static.csv.
- What is the price per square foot difference between Bay Farm Island, Alameda and Rockridge, Oakland?
- $250 per square foot: Bay Farm Island, Alameda $750, Rockridge, Oakland $1,000. Single-family medians, trailing twelve months. A median is not a valuation of any specific property.