Agriculture Ombudsman
University of California
Agriculture Ombudsman

Milk Processing

Welcome! You must be interested in making an artisan dairy product. Great! Sonoma and Marin Counties are home to family dairies of cows, goats and sheep and many great artisan milk products are made here, but there is room for more. Here we will cover the regulatory requirements, licenses required and provide additional resources to help you get started.

Milk Products & Grades

The term "milk product" will be used throughout unless the sentence refers to a specific milk product (i.e. cheese, butter, etc).

There are a variety of milk products on the market today - ice cream, yogurt, kefir, butter, cheese. In California, most milk products must be made with milk from a Grade A dairy. Grade A vs Grade B milk products:

Grade B Milk Allowed Grade A Milk Required
Ice Cream
All other milk products

What is the difference between Grade A and Grade B dairies? Not a whole lot. From Milk Standards: Grade A vs Grade B:

Milk from both Grade A and Grade B milk producers is checked regularly for: sight and odor, bacterial limits, somatic cell count (an elevated count is indicative of the presence of infection in the dairy cow), the presence of antibiotics, cooling temperature, and sediment. In addition, dairy farms are periodically inspected for compliance with water supply standards, and proper construction and maintenance for milking barns and milk rooms.

In order for a dairy farmer to be classified as a Grade A producer, the producer's facilities and milk must meet more stringent health and sanitation requirements than those of a manufactured grade (commonly called Grade B) milk producer.

In Sonoma & Marin counties, Grade A dairies are inspected twice a year; Grade B once a year. Contact the local dairy inspector before you start work on designing and building a new diary or if you are bringing a former dairy back online:

Kathleen Haase
Dairy Inspection, County of Sonoma & Marin

Organic or Conventional

In general, most cow dairies in Marin & Sonoma counties are Organic, this is because most of their milk is sold to the fluid milk market and pricing is better. For value-added product, such as cheese and ice cream, there is debate as to weather being organic is necessary.  

Artisan value-add milk products are expensive to make due to lack of economies of scale; if you own the dairy and are using all of the milk for value-added products, going organic may not be necessary. Research your market to know for sure.

Organic Milk Products

Organic milk products must comply with the following.

  • Milk from a registered organic dairy. Registration is required through California Department of Food & Ag. Register online, see "Cost Share Program" below the fess chart to help offset the registration fee.
  • Refer to 110820 p18 of California Organic Products Act:
    • Water, air and salt may be added (non-organic)
    • Non-organic product additives may not represent more than 5% of the weight of total finished product, excluding salt and water
  • If gross annual sales of organic product are greater than $5,000, your operation is required by law to become third party certified. If your sales are under $5,000 and you want to use the "USDA Organic" seal, you must become third party certified. CDFA provides a list of qualified certifiers on their site.

State Licenses

Milk processors must hold both a Milk Handler License and a Milk Product Plant License; both are issued by California Department of Food & Agriculture (CDFA):

Guidelines for the Sanitary Construction of Market Milk Dairy Farms

Milk Handler License is issued by CDFA

  • Required of every person who handles milk.

CDFA issues Milk Product Plant License

Zoning & Use Permits

If you want to make the product at the dairy, you will need to obtain approval from the county as that type of use is not allowed on ag zoned land by right. However, it is allowed. In Marin & Sonoma counties, if your plant is small, you will probably only need a zoning permit, which is ministerial. However, if you decide to grow the project beyond the zoning permit size, a far more costly and time-consuming conditional use permit will be required.

Either way, the permit is required to ensure that the waste will be handled properly and to minimize impacts to the environment and neighbors.

Marin County

Sonoma County

Building Permits

Nearly all buildings will require some sort of permit (there are exemptions). If you plan to construct a new building or modify an existing building to house your cheese plant, you will need a building permit. Anything from building to plumbing to electrical to remodels will most likely require a permit. Work on septic and well also require permits.

Marin County

In Marin County, you will work with the Community Development Department to obtain the permits.

Sonoma County

You will work with Permit & Resource Management Department to obtain necessary building permits. PRMD links:

CDFA Approval

The interior of the building must meet California Department of Food and Agriculture (CDFA) criteria. Refer to the Milk Plant Guidelines and contact the CDFA Dairy Program inspector for our area as soon as you are considering this project:

John Macy, CDFA Dairy Program

If you plan to have non-family members work in the creamery, California Building Code requires that the building and parking area meet accessibility requirements and accessible restrooms be provided.

Waste Water

North Coast Regional Water Quality Control Board - area in the Pacific Ocean watershed (most of the county). Scroll down to Permits-Diary Program.

San Francisco Bay Region Water Quality Control Board - area in the Bay watershed (parts of south county). Scroll down to Conditional Waiver for Dairies.

Map of Water Board Regions


Farm Labor – page on Sonoma AgOm site, we can use the same for the diary pages.


Make sure you and your business are covered for these activities. Farm Liability Insurance policies generally only cover farming activities (ag processing may not be considered a farming activity). You may need a Commercial General Liability coverage. Talk to your agent. 


View webinar Adding Value to Farm Products: Getting the Legal Ducks in a Row by Farm Commons to learn about insurance, employment laws, liability potential, and tax factors.

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