House hacking in Castro Valley (Castro Valley central).

What's actually happening in 94546

• Adopted / effective 2026-07-01

  Castro Valley BART with MTC TOC Tier 3 and SB 79 upzoning: 50–75+ du/ac within a half mile of the station, parking maximum 1.0. Alameda County

• Update underway

  CBD Specific Plan update underway. Alameda County

• Existing anchor

  Eden Medical Center (Level II trauma) in-ZIP. Alameda County

• Under construction / delivered

  The Chapter townhomes and Crescent Grove (72 affordable units). Alameda County

The numbers

Median price

~$1.3M (Castro Valley proxy)

Market rent

2bd $2,600 / 3bd $3,200 whole-home (underwriting band)

Property tax (Alameda County)

~1.33% effective (Castro Valley)

Per-bed rent band

$1,000–1,350/mo per bed

ADU rent band

$2,000–2,600/mo

Whole-home rent band

2bd $2,600 / 3bd $3,200 whole-home

Underwriting vacancy

5% underwriting vacancy

Appreciation scenarios

1.5 / 3.0 / 4.0 %/yr (conservative / base / upside)

Viability graded medium at this basis. Appreciation basis: BART plus TOC/SB 79 densities; SB 9 hillside-constrained; mid capex. Rent bands are city-level medians; confirm the specific parcel before trusting any of them. Run your own scenario in the calculator.

The house-hack angle

SFH-with-ADU near the station under the new TOC and SB 79 densities; room rentals to Eden Medical staff. SB 9 is hillside-constrained here.

What breaks it

• A ~$1.3M basis pressures a 3–10% down buyer: run the numbers cold
• SB 9 lot splits are hillside-constrained
• The CBD Specific Plan is an update in progress: designation ahead of capital