A vineyard on the Russian River in Alexander Valley usually comes with a riparian water right. That right covers less than many buyers assume. Under State Water Resources Control Board rules, a riparian right allows use of the river's natural flow only. Water imported from another watershed can't be used under it. Neither can water stored in a wet season for later use, or water released downstream from an upstream reservoir. For more than a century, the Potter Valley Project has diverted Eel River water into the upper Russian River and supplemented dry-season supplies from Potter Valley down to Healdsburg.
That project is being wound down. Public discussion has centered on whether Eel River water will keep arriving. Sonoma Water's latest modeling says it will. The model also shows that under the proposed replacement, most of that water would arrive in winter rather than in summer. For anyone weighing a vineyard purchase here, the useful question is which water a given parcel can lawfully use in July, and from which stored supply.
The right that comes with the river frontage
Riparian rights usually pass with the land when it sells. They are lost if a subdivision cuts a parcel off from the water and no steps were taken to preserve them. They can't be moved to an adjacent parcel, even one that touches the riparian parcel. They also can't be sold separately from the riparian land. All riparian holders on a stream share the same priority. When supply is short, they divide what exists according to need.
The 2021 drought showed how this works on the upper Russian River. On May 26, 2021, the State Water Board sent water-unavailability letters to 930 Upper Russian River right holders. It said roughly 1,600 upper river users could face curtailment as conditions worsened. A 2022 staff assessment states that all water-right holders in the watershed were curtailed in August 2021. Appropriative rights were cut back in order of priority date. Riparian rights, which have no priority dates, shared the available natural supply through water budgets the Board assigned. The Board rescinded every Russian River emergency curtailment order on March 29, 2023. Its drought page, last updated September 3, 2026, lists no newer order for the basin.
So the riverfront right already depends on natural flow, and the imported Eel River water has been the part of the summer system that riparian law never reached. That puts the timing of the replacement diversion at the center of the issue.
More Eel River water on paper, about the same water kept
The proposed replacement is the New Eel-Russian Facility, known as NERF. It would be a pump station with fish screens and conveyance to the existing Van Arsdale tunnel. The Eel-Russian Project Authority would run it as a run-of-river diversion. It would generally move water during wet-season threshold flows and stop in the dry season.
At an August 6, 2026 board meeting, Sonoma Water presented preliminary modeling that tested NERF against what actually happened from October 2024 through June 2026. The presentation splits each month into two figures. "Diverted" is the total moved across. "Stored" is what Lake Mendocino could hold or pass downstream for use instead of releasing it for flood control.
| Month | Actual diverted, ac-ft | Actual stored, ac-ft | NERF diverted, modeled | NERF stored, modeled |
|---|---|---|---|---|
| January 2025 | 2,805 | 132 | 12,894 | 3,132 |
| February 2025 | 2,130 | 0 | 16,658 | 0 |
| May 2025 | 6,799 | 6,799 | 3,073 | 3,073 |
| June 2025 | 7,145 | 7,145 | 1,070 | 1,070 |
| July 2025 | 7,603 | 7,603 | 243 | 243 |
| August 2025 | 3,197 | 3,197 | 0 | 0 |
| Oct 2024 to Jun 2026 total | 65,795 | 56,213 | 124,667 | 51,913 |
Over those 21 months, the model diverts nearly twice the water that actually crossed. The stored total comes out slightly lower, about 52,000 acre-feet against about 56,000 observed. The monthly rows show why. February 2025's large modeled diversion produced no stored water. July 2025 went from more than 7,600 acre-feet actually transferred to 243 modeled. Annual modeled transfers ranged from about 18,500 acre-feet in drought year 2021 to 86,800 in wet year 2017. Sonoma Water's summary says transfers would happen every year. Both statements hold. The annual volume continues, and the summer share falls sharply.
Why winter water is harder to keep
Storage is the limit. Sonoma Water's model estimates that in non-drought years, an average of about 40,000 more acre-feet a year could be used if the Russian River watershed had more storage. NERF moves water in winter, when Lake Mendocino may have little room. The model also includes a 3,000 acre-foot placeholder for a future Potter Valley storage project. Sonoma Water calls the analysis preliminary and says it will be refined.
The valley's growers read the outlook more cautiously. The Russian River Property Owners Association's plan for a proposed Alexander Valley Water District says losing Eel River imports could cause surface-water shortages in most years. In its comments to FERC, the Sonoma County Farm Bureau cited an analysis it commissioned. That analysis estimated $67.5 million in first-year direct economic losses from a 10% cut in Potter Valley Project water capacity. The figure is an industry-funded projection, not a measured loss. Much of the gap between these readings and Sonoma Water's comes down to seasonal timing and storage. Alexander Valley has 43 wineries and roughly 14,500 vineyard acres. The same river flows and connected groundwater also serve Cloverdale, Healdsburg, Geyserville, tribes and rural users.
The timeline still has no fixed date
PG&E filed its surrender and decommissioning application on July 25, 2025. It had been operating the project on annual licenses since the old license expired on April 14, 2022. Some coverage describes the license as surrendered. FERC's project page describes the application as pending environmental review, with scoping comments extended to September 18, 2026 and no surrender order posted. PG&E proposes removing Scott Dam and Cape Horn Dam, keeping only the infrastructure the replacement diversion needs.
Nine parties signed the Water Diversion Agreement dated July 16, 2025. They include Sonoma Water, Sonoma County, Humboldt County, the Mendocino County Inland Water and Power Commission, the Round Valley Indian Tribes and the California Department of Fish and Wildlife. PG&E did not sign. The agreement states that PG&E had not agreed to transfer its water rights, lands or other property. The agreement targets 2028 for decommissioning work to begin. The Eel-Russian Project Authority's August 2026 schedule shows design at 30 to 60 percent through the second quarter of 2027 and bid and award in 2031. KQED has reported that the dams will likely come out in the 2030s. A buyer closing today is likely to own through the changeover.
Alexander Valley's attempt to organize around it
The proposed Alexander Valley Water District would cover more than 28,000 acres along the river, from near the Mendocino County line south to Healdsburg. Cloverdale, Healdsburg, Geyserville, tribal trust lands and public lands would sit outside it. Its proposed services include expanding the voluntary water-sharing program, taking part in any future Eel-Russian diversion, managing groundwater and recharge. It would have a preliminary operating budget of about $500,000. Proponents gave $20 per irrigated acre a year as one example of an assessment. Landowners would vote on whether to form the district and would elect its board.
Sonoma LAFCO denied the district on May 6, 2026. A continued reconsideration hearing is noticed for October 7, 2026, where the commission may approve, amend, condition or deny the request. The outcome is not yet known. If LAFCO lets it proceed, landowners inside the boundary would still have to approve it. Cloverdale City Council member Andrés Marquez represents his city in the discussions. Healdsburg City Manager Jeff Kay gave the city's view in a statement to the Press Democrat:
"The proposed decommissioning of the Potter Valley project is a source of concern for all water users in the Russian River watershed, including Healdsburg. We understand the desire of Alexander Valley property owners to be organized and involved in discussions about water security for the future."
The paperwork that shows which water a vineyard holds
Summer supply will shift. That makes the documents behind a vineyard's water a pricing input as well as a closing formality. A review typically covers these points:
- Current records. CalWATRS has replaced eWRIMS, which is closed, so an old eWRIMS printout doesn't confirm current status. Check each right's source, point of diversion, season, quantity and place of use against the vineyard's actual works.
- Claims and confirmed rights. A Statement of Water Diversion and Use is a reporting record. The Board does not investigate its legal status. For unadjudicated riparian or pre-1914 claims, only a court decree confirms the right.
- Use history. A pre-1914 claim may be lost after five or more consecutive years without use. Riparian rights are not lost by non-use.
- Parcel lines. Board records are not reliably indexed by APN, because one right can span many parcels and parcel numbers change. Cross-check right IDs against deeds, maps and decrees, especially after any past lot split.
- After closing. The Board must be notified of an ownership change within 30 days through CalWATRS. Annual reports for October 1, 2025 through September 30, 2026 are due January 31, 2027.
- Measurement. The revised measurement regulation starts with Water Year 2027, which began this October. It generally applies to rights above 10 acre-feet a year, and devices and methods must be registered by January 31, 2027. Ask for the meter inventory and the reported diversion data, not only a seller's estimate of seasonal use.
A surface-water right does not grant a groundwater entitlement, so wells need their own local review. Sonoma County's well rules are also in flux. On August 4, 2026, a state appeals court ruled that the county must complete CEQA review of its amended well-permitting ordinance. This is general background, not legal advice. Each parcel's water position needs review by qualified water counsel.
If you are buying or selling Alexander Valley vineyard land, Graham Sarasy can help you put together the water-rights record, reported diversions and storage facts before price is set. Request a confidential consultation.
