The water situation

TL;DR

The facts on file

• Three wells; only one tested. The southwest primary is certified at 4.0 GPM with 100% recovery (tested by Jerry & Don's, 2021). Low instantaneous flow, but it refills fully; specific capacity 0.1 gpm/ft — a tight bedrock well. The other two wells have no yield or quality data on file.
• ~45,000 gal of storage across the property — though only 20,000 gal of it (four 5,000-gal concrete tanks) is actually documented.
• Water quality has never been tested. No potability or ag-suitability panel exists anywhere in the record.
• The aquifer is healthy. A hydrogeologic study placed it in a Class 2 major-recharge zone — ~11,933 ac-ft stored, ~247 ac-ft/yr recharge — with no overdraft and no impact to neighboring wells, and judged even a heavy modeled draw (~2.3 ac-ft/yr) sustainable. Current ag use is only ~0.66 ac-ft/yr.
• Clean history. No dry-well events, no water-supply restrictions, and no disclosed defects in the wells or plumbing.

What we can reasonably conclude

• The resource isn't the worry — getting it out is. The basin clearly holds plenty of water; the real variable is this property's extraction capacity. One 4 GPM well plus ~45k gal of storage easily covers today's light ag use, but is modest for an intensive, irrigation-heavy ag project.
• The two untested wells likely decide the question. If they're decent producers, combined capacity could be ample; if not, a serious operation would be leaning hard on one modest well and storage.
• Quality is a genuine unknown — and it matters twice. Potability for any future residence, and ag-suitability (salinity, boron, nitrate, sodium) for whatever you grow. Neither has been measured.
• Net: promising but unproven. Healthy basin, one good-but-modest proven well, two unknowns, and zero quality data.

If we make an offer — water contingencies & inspections

• Put a water/well contingency on any offer. Make it explicit: the right to test all three wells, with a minimum-yield threshold and acceptable water-quality results you define, and a walk-or-renegotiate right if they aren't met.
• Call Jerry & Don's Yager Pump & Well first — (707) 762-1473. They ran the 2021 test and service all the wells twice a year, so they know the real-world behavior better than any document. Ask: how do all three wells actually perform, especially late dry-season? what's the realistic combined deliverable yield? how is the storage plumbed, and is it enough? and what would it take to support a bigger ag draw — a deeper or new well, more storage? Low cost, high signal — do this before spending on formal tests.
• Test before close, under the contingency. A dry-season yield test on the primary and pump tests on both backups; a full potability + ag-suitability water panel (coliform / E. coli, nitrate, arsenic, boron, EC/salinity, SAR, pH, hardness); and pull the DWR well-completion reports for all three wells.
• Get the full hydrogeologic report. The study below is only summarized in the permit file — request the original (Hurvitz Environmental, 2022) for its well-interference and drawdown detail.
• If the ag vision is irrigation-intensive, add a hydrogeologist / ag-well consult to size wells and storage to the actual plan before committing.

Who inspected the wells

There is one formal well inspection in the record — a yield-certification pump test on the primary well. (It exists because the prior owner's cannabis application required proof of water sufficiency; for us its value is simply that it's real, paid-for water diligence we inherit.) It's filed under two cover pages: Permit Sonoma's WLS-010 certification form and the contractor's own Well Test Report #1493.

Performed by

Jacob Emschweiler — field technician, California Lic. C-57 #424778

Approved by

Jim Mickelson

Company

Jerry & Don's Yager Pump & Well — 1290 Bodega Ave, Petaluma, CA 94952 · (707) 762-1473 · Lic. C-36 / C-57 424778

Date of test

2021-09-08 (report #1493); filed to Permit Sonoma 2021-09-30

Commissioned by

Mike Agins (owner / Bloomfield Farms, LLC)

Also the incumbent

Jerry & Don's services the wells and pumps bi-annually — so they know this system well, and are the obvious first call

Source: Well Documents — WLS-010 Certification + Jerry & Don's Well Test Report #1493 (5 pp). Servicing arrangement confirmed in the Seller Property Questionnaire.

The certified well — Wel 21-0414

This is the site's primary domestic/irrigation well, near the southwest corner of the parcel. Here's what the 2021 test measured.

How to read 4.0 GPM. That's genuinely modest — about 240 gallons an hour. But the well showed 100% recovery: it refills as fast as it's drawn, and storage buffers the gap between a steady trickle and peak demand. Current ag use (~0.66 ac-ft/yr ≈ 590 gal/day) is easily covered — roughly two to three hours of pumping a day. The caution is scale: a serious irrigated-ag operation can need many times that, and one 4 GPM well — even backed by storage — won't carry it alone. That's exactly why the two untested wells, and the combined deliverable yield, are the number that matters for an ag plan. The low specific capacity (0.1 gpm/ft) is typical of west-Sonoma bedrock wells.

Source: Well Documents — WLS-010 form (p. 1), pump-test data log (p. 2), Well Test Report #1493 well data (p. 4), and the water-quality panel left N/A (p. 5).

Water tanks & storage

The seller's amenities list claims ~45,000 gallons of water storage. Only part of that is documented:

Documented

(4) × 5,000-gal concrete tanks = 20,000 gal, recorded on the certified well system (Well Test Report #1493)

Claimed total

~45,000 gal across the property (seller's amenities list)

Undocumented

~25,000 gal — type, location and condition not itemized anywhere in the packet Verify

Pressure system

WX-201 pressure tank at 130 psi; well-pump static pressure 140 psi

Other water infra

A storm-water retention pond + drainage, from the prior site-prep work

Storage is doing real work here. With a modest-yield well, the tank capacity is what lets the property meet peak demand — so the true storage figure matters. Confirm the undocumented ~25,000 gal actually exists and is serviceable; for an intensive ag plan, expanded storage is one of the cheaper ways to stretch a low-yield well.

Where the four tanks sit matters. The Transfer Disclosure (§C.7) reports that soil can slump on the west-side slope "below the 4 water tanks" during extreme rain — it's happened "a few times in 24 years," each time cleared with a tractor and the perimeter road rebuilt. So the concrete-tank pad sits above a known, minor, recurring slump zone. Combined with §C.6 (the pad sits on extensive select fill over a former quarry floor), the west-side ground near the storage warrants a geotech look before relying on or expanding that pad.

Sources: Seller list of Amenities (~45,000 gal, 3 wells); Well Test Report #1493 (the 4 × 5,000-gal concrete tanks, p. 4); Transfer Disclosure (TDS) §C.6 (fill) and §C.7 (slump below the 4 tanks).

The three wells

The parcel has three active wells (confirmed in both the seller's amenities list and the hydrogeologic study). Only the primary has any test data:

Only the primary well has been tested. The two others are confirmed to exist but carry no yield, depth, or completion data in the disclosure set — pulling their DWR well-completion reports and pump-testing them is the single highest-value water diligence step. Source: Seller list of Amenities; hydrogeologic study (in the permit Initial Study / MND).

Basin & aquifer capacity

The prior owner's permit work left behind one genuinely useful asset: a basin-wide hydrogeologic study (Hurvitz Environmental, 2022). Its conclusions are about the aquifer, so they hold regardless of what the land is used for — and they're reassuring on the question of whether the resource can support a serious ag draw.

Groundwater setting

Sonoma County Groundwater Availability Class 2 (Major natural recharge); not a priority basin; "very low priority" under SGMA

Aquifer storage

~11,933 acre-ft stored in the study area

Annual recharge

~247 acre-ft/yr (≈123.5 ac-ft in drought years)

Current onsite use

~0.66 acre-ft/yr (horses + landscaping today)

Heaviest modeled draw

~1.27 ac-ft/yr net (the study even modeled a full cultivation operation on top of existing ag) — still well under 1% of recharge

Verdict

Sustainable — no overdraft, and no significant impact to neighboring wells or streamflow

What this means for an ag project. At the resource level there's ample headroom — current use is a rounding error against annual recharge, and even a far heavier draw was judged sustainable with no overdraft and no harm to neighbors. So the basin is a green light. The limiter is purely on-site: how much you can physically extract and store. Scaling water for serious ag here is an infrastructure question (wells + storage), not a question of whether the water is in the ground.

Source: Hydrogeologic study, summarized in the CEQA Initial Study / MND — water-supply narrative and Table 4 (p. 52). The underlying report (Hurvitz Environmental Services, 2022-01-26) isn't in the packet; request it from the listing agent for the full well-interference and drawdown analysis.

Where the water stands today

As it runs now: the wells and ~45,000 gal of storage have supported a commercial vegetable farm, a horse-boarding operation, livestock and landscaping for years on roughly 0.66 acre-ft/yr of groundwater, with the certified primary at 4.0 GPM / 100% recovery. The seller discloses no dry-well history (no county drought-tank assistance), no water intrusion, no defects in the well or plumbing, and no restrictions or surcharges on the wells or groundwater. For the current level of use, the water has been sufficient and uneventful.

For a future residence: the same wells should comfortably serve a modest house alongside continued ag use — the binding constraints are storage and the (untested) potability of the water, not flow. Test before you trust it.

For a serious ag operation: this is where it gets real. Whether the property can water an intensive, irrigated ag use comes down to combined deliverable yield across all three wells plus storage — and right now two-thirds of that capacity is unmeasured. The aquifer can supply it; proving the on-site infrastructure can is the work to do before committing.

Sources: Seller Property Questionnaire (SPQ) §§8–10 (no dry-well assistance, intrusion, or well restrictions); Transfer Disclosure (TDS) (water supply = private well; septic).

Sources: SPQ §10.C; hydrogeologic study / Initial Study (no Class I/II streams on-site; ephemeral Class III drainages only).

Source documents

Every figure on this page traces to one of these — the seller's disclosure packet and the permit-era water studies, mirrored here so you can read the original alongside the finding.