NorCal Civil Engineering Inc

05/11/2026

Napa County Affordable Accessory Dwelling Unit program to host information sessions

Homeowners in Napa County, including American Canyon, Calistoga, Napa, St. Helena, Yountville, and the unincorporated Homeowners in Napa County, may be eligible for a forgivable loan of up to $105,000 to build an Affordable Accessory Dwelling unit (AADU).

The Napa County Affordable ADU (AADU) Program is designed to expand affordable housing and increase flexible housing options for homeowners and the local workforce. Homeowners interested in building an affordable ADU and renting it to an income-qualified tenant are invited to attend upcoming information sessions on Wednesday, May 13, 2026 in American Canyon or on Thursday, June 11, 2026 in Calistoga.

The informational sessions will cover:

* Loan Amounts: Forgivable loans ranging from $60,000 to $105,000, depending on unit size and project-specific conditions
* Loan Forgiveness: Loans are fully forgiven over a five-year period when program requirements are met
* Tenant Eligibility: Requirements for income-qualified tenants and how the County supports tenant certification
* Building an ADU: Overview of the development process, including information from the Napa Sonoma ADU Center and County planning and building staff

Whether homeowners are in the early planning stages or ready to build, these sessions provides a clear roadmap to help homeowners benefit from the Napa County Affordable ADU program.

American Canyon Event Details: Learn About Napa County's Affordable ADU Forgivable Loan Program
Date: Wednesday, May 13, 2026
Time: 6:00-7:30 p.m.
Location: American Canyon City Hall, 4381 Broadway Napa
Live Spanish translation provided.
RSVP: Learn about Napa County's Affordable ADU Forgivable Loan Program Tickets, Wednesday, May 13 • 6 PM - 7:30 PM | Eventbrite

Calistoga Event Details: Learn About Napa County's Affordable ADU Forgivable Loan Program
Date: Thursday, June 11, 2026Time: 6:00-7:30 p.m.
Location: Calistoga Community Center, 1307 Washington Street, Calistoga
RSVP: Learn about Napa County's Affordable ADU Forgivable Loan Program Tickets, Thursday, June 11 • 6 PM - 7:30 PM | Eventbrite

04/02/2026

Napa River Flood Protection Project

https://www.napacounty.gov/1083/Napa-RiverCreek-Flood-Protection-Project

This is an interesting project that has moved into a new phase as shown by the map. Have you checked out the new features yet?

03/17/2026

Napa County Groundwater Sustainability

The NCGSA adopted Resolution 2025-05 on December 9, 2025, to implement Groundwater Sustainability fees in the Napa Valley Subbasin, as authorized by Water Code § 10730 to support implementation of the Groundwater Sustainability Plan. The Groundwater Sustainability fees were established based on the Rate and Fee Study (December 2025).

Properties in the Napa Valley Subbasin, excluding those in the City of Calistoga, City of St. Helena, City of Napa, and the Town of Yountville municipal service districts, are subject to the ground water fees.

Find out if your property is subject to this fee .https://www.napacounty.gov/3983/Groundwater-Sustainability-Fee

02/12/2026

Wet Weather Septic System Evaluations in Sonoma and Napa Counties

What Property Owners and Buyers Need to Know
In Sonoma and Napa Counties, wet weather groundwater testing is a critical part of septic system evaluation and permitting. Because both counties have areas with high seasonal groundwater, clay soils, vineyards, and sensitive watersheds, local environmental health departments require careful review of septic system performance during the rainy season.
If you are building, replacing a system, or buying property with septic, understanding wet weather requirements can save time, money, and major headaches.
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Why Wet Weather Testing Matters in Wine Country

Septic drainfields rely on unsaturated soil to treat wastewater. During Northern California’s rainy season (typically November–April):
• Groundwater levels rise
• Clay soils become saturated
• Drainfields may lose vertical separation
• Effluent treatment effectiveness can decrease
• Systems may back up or surface
Both counties require confirmation that adequate separation exists between the bottom of the drainfield and the seasonal high groundwater table.
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Sonoma County Septic Requirements

Sonoma County Permit Sonoma Environmental Health Division oversees onsite wastewater treatment systems (OWTS).
Wet Weather Groundwater Determination
Sonoma County:
• Establishes an official “wet weather testing period”
• Opens testing only after sufficient cumulative rainfall
• Requires groundwater observations during this period for many
new or replacement systems
Testing may involve:
• Excavated test pits
• Observation holes
• Temporary monitoring wells
• Soil profile evaluation for redoximorphic features (indicators of
seasonal saturation)
Vertical Separation
Typical minimum vertical separation:
• 2–4 feet between trench bottom and seasonal high groundwater
(Exact requirement depends on system type and soil conditions.)
If insufficient separation exists, alternatives may include:
• Raised mound systems
• Engineered systems
• Pressure distribution
• Sand filtration components
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Napa County Septic Requirements

Napa County Environmental Health also requires wet season groundwater evaluation for many new and replacement systems.
Key elements include:
1. Soil Profile Evaluation
• Identification of seasonal high groundwater indicators
• Soil texture and structure analysis
• Depth to limiting layers
2. Wet Season Testing Window
• Evaluations must occur during the rainy season
• Rainfall thresholds must be met
• Field observations are documented by a Qualified Professional
3. Replacement Area Requirement
Napa County requires a designated replacement drainfield area that must also meet groundwater separation standards.
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When Wet Weather Testing Is Required

You may need wet weather testing if you are:
• Building a new home
• Replacing a failed septic system
• Expanding a home (bedroom additions increase septic design
flow)
• Subdividing property
• Developing vineyard housing or rural structures

For real estate transactions, wet weather testing is not always automatically required, but it is strongly recommended if:
• The system is older
• The property is near a creek or floodplain
• The area is known for high groundwater
• There are signs of seasonal saturation
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What the Evaluation Process Looks Like

1. Hire a Qualified Professional (QP)
Typically a civil engineer, registered environmental health
specialist, or licensed septic designer.
2. Soil and Site Evaluation
o Test pits dug to 7–10 feet (or refusal)
o Soil logged and described
o Groundwater indicators documented
3. Wet Weather Observation
o Groundwater measured during rainy season
o Rainfall totals verified
4. Percolation Testing (if required)
5. Report Submission to County
6. County Review and Approval
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Common Challenges in Sonoma & Napa

High Clay Content Soils
Slow percolation and drainage limitations.
Shallow Bedrock
Limits trench depth and vertical separation.
Seasonal Perched Water Tables
Common in valley areas.
Creek and Watershed Protection
Additional setbacks may apply near water bodies.
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Costs to Expect

Wet weather testing and site evaluation typically cost:
• $2,500–$6,000+ for evaluation and reporting
• More if monitoring wells are required
• Engineered systems can range $20,000–$50,000+ if site
constraints exist
Costs vary widely based on terrain, soil, and complexity.
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Tips for Property Buyers

If purchasing in Sonoma or Napa:
• Request septic records from the county
• Confirm permit history
• Ask when the system was last pumped
• Consider a wet weather evaluation if buying in winter
• Verify there is a code-compliant replacement area
A failing septic system in these counties can significantly impact property value and escrow negotiations.
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Bottom Line

If you’re planning development or purchasing rural property, consult a local Qualified Professional early in the process. Wet weather testing windows are seasonal — missing the rainy period can delay your project until the following winter.

12/18/2025

As reported in the Press Democrat, the Napa County Board of Supervisors on Tuesday approved the county’s first effort to define how a new state law that opens up tasting experiences directly in vineyards will work in the Napa Valley.

The pilot program implementing that law, Assembly Bill 720, is set to run from Jan. 1, 2026, to July 1, 2027, while county staff work to figure out permanent rules. The new law allows wineries to host small “estate tasting events” at vineyard sites with only a permit from the state Department of Alcoholic Beverage Control when it becomes effective.

California Assembly Bill 720 (AB 720) for the 2025-2026 session significantly impacts wineries by creating a new permit for off-site vineyard tastings, offering them more flexibility, and delaying
California Redemption Value (CRV) labeling deadlines for wine containers, allowing more QR code use. It allows for "pop-up" tastings at controlled vineyard sites, pushes the main CRV label date to 2026, and offers regulatory relief for existing bottled wine.

Key Provisions of AB 720 (2025-2026 Session)
• Estate Tasting Event Permit: Allows wineries to host tastings at non-adjacent vineyards they control, offering new consumer experiences.
• CRV Labeling Relief: Extends the deadline for new wine containers to have CRV indicia from July 1, 2025, to July 1, 2026.
• Exemptions: Delays the permanent exemption for already-bottled wine from CRV labeling to July 1, 2025.
• QR Code Flexibility: Permits the use of smaller, half-inch QR codes for compliance.
• Fees & Limits: Imposes a $200 annual fee for the new permit and limits it to 36 events per licensee yearly, with transferability.

Why It Matters
• For Wineries: Provides greater freedom to host unique tasting experiences and more time to comply with complex recycling regulations.
• For Consumers: More opportunities for authentic wine experiences at vineyard sites.
• Economic Impact: Supports California's wine industry by easing regulatory burdens and fostering tourism.

Bill Status
• Introduced in February 2025 and passed, becoming Chapter 562, Statutes of 2025, in October 2025, making it law.

12/15/2025

10/29/2025

California Building Codes are set to change on January 1, 2026, impacting all new building projects. In Sonoma County, the Permit Sonoma offices are hosting three Zoom meetings to explain and answer questions on the code changes. There is still time to submit your building project for review under the 2022 codes requirements, but don't wait too long and make sure your package is complete with all the required documentation for review.

The Building Division inspects construction projects after the building permit has been issued. They review projects inside and out to make sure they are built according to the approved plans and building codes. The focus of this division is on protecting public health and safety.

10/14/2025

The California Water Boards SWAMP Bioassessment program helps us to understand stream health using biological data collected from our waterways.
Here is an overview from them and the beta version of the dashboard to check out the data housed on the site.
Protecting the ecological integrity is part of understanding it and sharing with the community.
https://www.waterboards.ca.gov/water_issues/programs/swamp/bioassessment/
https://gispublic.waterboards.ca.gov/swamp-data/

07/31/2025

Permit Sonoma adjusts issued permits to fall in line with the State expiration requirement. Instead of the previous three year time frame to complete a project, now it is 1 year effective August 1, 2025. Progress needs to be shown within that twelve month period or the permit could be marked as expired. It could mean potential extra cost if a new permit has to be submitted to the county. Improved management of the project overall, from start to finish, to meet the new requirements will have to be considered during the concept stage to allow for this constraint.

07/15/2025

Planning a Construction Project in Unincorporated Sonoma County?

All construction projects in unincorporated Sonoma County that require a building permit must follow CALGreen recycling and reporting requirements. To simplify the process, Permit Sonoma has partnered with Green Halo a free, web-based system that helps you track and report your recycling efforts.
Here, you’ll find everything you need: step-by-step instructions, training guides, and helpful tools to create an account, submit your recycling plan, and log your recycling tickets.

Recycling Requirements:
• Recycle 100% of inert materials (e.g., concrete, asphalt, soil, stone, and fines)
• Recycle at least 65% of all other construction materials

https://wastetracking.com/city/sonomacounty/