Red Hills Lake County Vineyards: Volcanic Uplands, Winery Permits, Wells and Wildfire

By Matthew Martinez, Founder, CEO & Managing Broker, Diamond Real Estate Group. California DRE #01869679.

Red Hills Lake County is an upland appellation on the southwestern shore of Clear Lake, between Kelseyville and Lower Lake, rising from the lakeshore to some of the highest vineyard ground in the Clear Lake AVA. Its boundary is drawn largely on elevation contours, its red volcanic soils are the reason for the name, and TTB expanded it in 2024. For owners, the issues that matter most are which Lake County permit a winery or tasting room needs, how the vineyard is watered on hillside ground, and wildfire.

Red Hills Lake County at a glance

Where the appellation runs

The current rule at 27 CFR 9.169 describes a 38-step boundary on four USGS quadrangles (Clearlake Highlands, Lower Lake, Whispering Pines and Kelseyville). It starts on the Clear Lake shoreline south of Slater Island, climbs to the 1,400-foot contour, follows Seigler Canyon and Perini Creeks and the 1,800-foot contour on the south side, then Copsey and Bad Creeks, Big Canyon Road and Loch Lomond Road past Seigler Springs. On the west it crosses the summits of Seigler Mountain and Mt. Hannah, reaches the 2,800-foot contour near Boggs Lake, and follows Harrington Flat Road and Bottle Rock Road. It returns along Highway 29/175, Wilkinson Road, Konocti Road, Konocti Bay Road and Soda Bay Road to the lake. Because so much of the line is a contour, a single ranch can have blocks inside and outside the appellation; an elevation survey of each block is worth the cost.

The TTB AVA list places Red Hills Lake County within the Clear Lake and North Coast AVAs. Clear Lake also contains Big Valley District-Lake County, Kelsey Bench-Lake County, High Valley and Upper Lake Valley, so parcels near Kelseyville should be checked against the Big Valley District and Kelsey Bench lines as well.

The 2024 expansion

TTB’s expansion rule, T.D. TTB-190, effective March 6, 2024, added about 679 acres in three separately owned parcels west of Bottle Rock Road. The rule found that about 90 percent of the added land has volcanic soils matching the original AVA, although the area west of Bottle Rock Road also has large serpentine soil areas. It also notes features that matter to growers: slopes from near zero to over 30 percent, some of the highest elevations in the Clear Lake AVA, a lake influence that helps reduce frost risk (some growers still use frost protection), harvests that rarely start before October 1, and less fog with warmer temperatures than much of the North Coast AVA. Blocks in the expansion area may have been labeled under Clear Lake before 2024.

For the full picture of Lake County’s appellations, see our Lake County vineyards page and California wine regions guide.

Zoning and winery permits

Red Hills is unincorporated, so Lake County’s Zoning Ordinance controls. In the Agriculture ("A") district, Article 5 sets out a clear ladder:

• Permitted: agricultural processing buildings up to 5,000 square feet and one produce stand per parcel.
• Minor use permit (Sec. 5.4(c)): small wineries producing 15,000 cases or less with up to 750 square feet of retail space; wine tasting facilities up to 750 square feet on sites with at least 10 acres of planted vineyard; a restaurant up to 750 square feet accessory to a tasting room; and winery promotional and non-promotional events, with non-promotional events reviewed after one year.
• Major use permit (Sec. 5.5): large wineries above 15,000 cases, and any small winery or tasting facility that wants amplified outdoor public events (also reviewed after one year).

Development standards in the A district include a 40-acre minimum lot size, a 500-foot minimum average lot width, a 5:1 maximum length-to-width ratio, and a 50-foot height limit for agricultural accessory structures. Other districts, such as Rural Lands (RL) and the Agricultural Preserve zone, have their own use lists, so confirm the parcel’s district on the county’s Zoning Ordinance page and ask Community Development how existing approvals carry over to a new owner. State ABC licensing and TTB permits are separate; see winery license transfer and how to start a winery.

Water on volcanic hillsides

Unlike valley-floor Lake County vineyards, many Red Hills blocks sit on hillside volcanic ground above the main alluvial basins, so water usually comes from private wells, ponds or springs. The Lake County Watershed Protection District’s groundwater data page explains that staff measure wells in seven major basins, normally in April and October, and warns that individual wells can differ substantially from basin summaries, with shallow wells more likely to have problems. In nearby Big Valley, the District monitors six wells influenced mainly by Adobe Creek and six by Kelsey Creek each month, and a water quality program is starting under the Big Valley Basin Groundwater Sustainability Plan. Parcels toward Kelseyville should be checked on DWR’s basin prioritization map to see whether that plan applies.

For upland parcels, ask for well completion reports, a pump test run in late summer, water quality results and the history of any pond or spring diversion. If frost protection is used, confirm the water source and equipment. See vineyard water rights, vineyard ponds and reservoirs and our Lake County water, sewer and septic records guide.

Wildfire, smoke and insurance

Southern Lake County has a recent and severe fire record. CAL FIRE’s file on the Valley Fire shows it began September 12, 2015, burned 76,067 acres in southern Lake County, destroyed 1,958 structures including 1,280 homes, and caused four confirmed civilian deaths. Check whether the specific parcel was inside that or any other fire perimeter, and review its rebuild history.

CAL FIRE’s Fire Hazard Severity Zone maps rate land as Moderate, High or Very High, and the State Responsibility Area maps took effect April 1, 2024. Insurance availability can shape a deal here, so get quotes early. See wildfire smoke taint, vineyard and winery insurance and our Lake County wildfire, insurance and rebuild records guide.

Williamson Act land

Agricultural Preserve land in Lake County is often under Williamson Act contract. According to the Department of Conservation, contracts bind every later buyer, renew each year on rolling 10-year terms (20 years under a Farmland Security Zone), and can be cancelled only by the landowner with a 12.5% fee. Read the recorded contract before planning a homesite split or non-farm use; our Williamson Act guide has more.

A due diligence list for a Red Hills Lake County vineyard

• Survey each block against the 27 CFR 9.169 contours, and against the 2024 expansion line west of Bottle Rock Road.
• Near Kelseyville, also check the Big Valley District and Kelsey Bench boundaries.
• Confirm the zoning district and which winery, tasting or event permits are in place under Article 5 (or the applicable district).
• Verify that the 10 planted vineyard acres required for a tasting facility in the A district exist and are documented.
• Get well logs, late-summer pump tests and water quality results; document ponds and springs.
• Check whether the parcel overlies a monitored basin and whether the Big Valley plan applies.
• Review fire history, the hazard zone, defensible space, road access and insurance quotes.
• Check for serpentine soils on newer blocks, especially west of Bottle Rock Road.
• Obtain any recorded Williamson Act contract.
• Work through the vineyard due diligence checklist.

Questions people ask

Sources & notes

1. 27 CFR 9.169 Red Hills Lake County, 2025 CFR edition via GovInfo (current text at eCFR Part 9)
2. TTB final rule: T.D. TTB-190, Expansion of the Red Hills Lake County Viticultural Area, 89 FR 7618 (Feb. 5, 2024)
3. TTB: Established American Viticultural Areas
4. County of Lake: Zoning Ordinance Article 5, Agriculture District and Zoning Ordinance index
5. Lake County Watershed Protection District: Groundwater data
6. DWR: Basin prioritization
7. CAL FIRE: Valley Fire incident record
8. CAL FIRE Office of the State Fire Marshal: Fire Hazard Severity Zones
9. California Department of Conservation: Williamson Act questions and answers

General information, not legal or tax advice. Last reviewed November 2026 by Matthew Martinez.

Related: Lake County vineyards · Kelseyville real estate guide · Lower Lake real estate guide · Lake County real estate guide · Anderson Valley vineyards · Vineyard due diligence · Vineyard water rights · All vineyard and winery guides