Implied 1% ad valorem property tax (Prop 13): ~$11,014/yr base, plus voter-approved overlays. Total tax bill (incl. parcel fees) likely ~$12,500–14,000/yr. The Mosimans appear to have held it for at least 15+ years based on the ENC09-0030 permit filing date (2009), but possibly significantly longer — the low assessed value relative to the obvious land-market reality is consistent with a long Prop 13 hold.
All buildings small along this corridor (highest building value $413K, most well under). These are predominantly rural-residential and ag parcels where building value < land value.
Land $/sf varies dramatically:
3845 Bloomfield: $0.45/sf
4201 Bloomfield: $0.27/sf
4707 Bloomfield: $0.20/sf
4500 Bloomfield: $1.70/sf (small lot, premium)
4400 Bloomfield: $0.72/sf
3845’s land value of $1.0M on 51 acres = $19.6K/acre assessed. Hanson’s 4707 (113 ac) at $1.0M = $8.9K/acre assessed. Hanson’s deeper hold (2001 acquisition) compresses the per-acre Prop 13 base; 3845’s higher per-acre tells you the Mosimans almost certainly purchased more recently — likely 2007–2009 (consistent with the 2009 first permit filing) — at the top of the pre-GFC ag-land market.
3845 carries the lowest building value of any parcel on the corridor ($100,763 — far below 4201’s $413K barn or 4500’s $349K residence). Consistent with the parcel having a small 1925 dwelling and not much else permitted.
Notes / caveats
The city-data page header lists multiple owner names parenthetically. “(TOM BIRSE ET AL)” sits next to 3858 Bloomfield, not 3845 — Birse is the neighbor to the northwest per the OnX map and matches that address. 3845’s owner per Permit Sonoma is unambiguously MOSIMAN.
Rehold lists “M Gaggero” as a resident at 3845 Bloomfield. Could be a former tenant or a data error; not corroborated by any other source.