Value Notices and Property Tax Information

We send construction questionnaires to the property owner of record after a building permit is issued. If your project is still open by the end of the year, we may send a follow-up questionnaire in late December.

City and town building departments do not notify us when a project is finished or a permit is finalized. Completing the questionnaire helps us update your property record and close the permit in our system.

Yes. We may send more than one questionnaire during your project to track progress. Even if nothing has changed, returning each form helps us keep your project record accurate and complete.

You have two options:

• Mail it back
• Scan and email both sides to the appraiser listed at the top of the form

Currently, there is no online version of the questionnaire.

We receive permit information directly from city and county building departments. If you think a permit was issued in error, call us at 415-473-7215 (CA Relay 711) so we can help.

Your notice will include:

• Owner name and mailing address
• Property location and parcel number
• Event date (sale or construction completion)
• Assessment date and tax year
• A breakdown of your value change and how it was calculated

The supplemental value is the difference between your new assessed value and the previous one. This amount is prorated based on how many months remain in the fiscal year (which ends June 30).

If the value decreased, you may receive a refund or negative tax bill. This will not change your regular annual tax bill, which you must still pay on time.

• Sale date: October 8, 2022
• Old assessed value: $300,000
• New market value: $995,000
• Difference: $695,000
• Months remaining in fiscal year: 8
• Proration factor: 8 ÷ 12 = 0.67

Your supplemental bill would be:
$695,000 × 0.67 × tax rate = bill amount

You may qualify for a $7,000 reduction in assessed value on your supplemental bill if:

• You live in the home as your primary residence within 90 days of purchase or new construction
• The property was not already receiving the exemption

To apply:

• Submit a Homeowners’ Exemption Claim Form within 30 days of the date on your notice
• If you file by the due date of the first installment, you can still receive a partial ($5,600) exemption

This exemption only applies to bills that show an increase in value.

Yes. If you disagree with the value:

• Contact the appraiser listed on your notice
• If needed, file a formal appeal with the Assessment Appeals Board
• Deadline: 60 days from the mailing date on your notice, bill, or refund check
• Appeal info: call 415-473-7345 (CA Relay 711) or visit the Assessment Appeals Board website

❗ Filing an appeal does not delay payment. You must still pay your bill on time to avoid penalties. If your appeal is successful, you’ll receive a refund.

All property tax bills, including supplemental bills, are managed by the Marin County Tax Collector:

• Phone: 415-473-6133 (CA Relay 711)
• Location: Marin County Civic Center, Room 202
• Hours: Monday to Friday, 9 a.m. to 4:30 p.m. (closed holidays)

When is my supplemental bill due?
The due date is printed on the bill. It varies depending on the mailing date.

Will I be taxed for the entire year?
No. You’re only taxed for the portion of the fiscal year that remains after your purchase or construction completion date.

Why did I receive two supplemental bills?
You’ll get two bills if the event occurred between January 1 and May 31:

• 1st bill: covers the rest of the current tax year
• 2nd bill: covers the full next tax year

Events between June 1 and December 31 only generate one bill.

Sold shortly after buying?
If you sold the property soon after purchase and received a bill, contact the Assessor’s Office:

• Phone: 415-473-7215 (CA Relay 711)
• Location: Civic Center, Room 208
• Hours: Monday to Friday, 9 a.m. to 4 p.m.

No. You are only taxed on the supplemental value for the portion of the current fiscal year remaining after you purchased the property or completed new construction.

If you add to or significantly improve your property, the Assessor may reassess the value of that new construction.

The Assessor receives copies of building permits from city and county building departments. If the changes to your property are considered new construction, an appraisal is done to determine the market value of the new portion only. Routine repairs are not reassessed.

Examples of assessable new construction include:

• Adding a room, second story, or garage
• Finishing a basement or attic
• Building a pool, spa, or patio
• Converting space to living areas
• Major kitchen or bathroom remodels with upgrades

Examples of work that is not assessed:

• Replacing a water heater or HVAC system
• Upgrading windows or flooring
• General maintenance or repairs
• Painting, patching, or refinishing

You can file an appeal if you believe the new assessed value is too high. Visit the Assessment Appeals Board website or call 415-473-7345 (CA Relay 711) for more info.

Our office finds out about new construction through:

• Building permits
• Property transfers
• Information from the public
• Field visits by Assessor staff

Even if you didn’t get a permit, the law requires the Assessor to value all new construction.

Example: partial remodel

If you added a new bedroom and bathroom, only that new part is reassessed—not your whole property. The increase is based on the market value, not the cost of construction.

Example: full rebuild

If you tear down and rebuild your home—even if you leave one wall standing—it is considered entirely new construction. Your property will be fully reassessed.

We decide if a remodel is the equivalent of new based on the extent of work.

May be considered new:

• Structural changes
• Moving or removing walls
• Major electrical and plumbing upgrades
• Full kitchen or bathroom remodels with upgrades

Not usually considered new:

• Painting
• Replacing carpet
• Moving electrical outlets
• Non-structural tenant improvements

If your project is not done by January 1 (lien date), we’ll assess the value as of that date. Once complete, the full value of the newly constructed portion will be reassessed.

• Construction is complete when the space is:
• Approved for use by building officials, or
• Usable based on clear visual signs, or
• Done according to the builder’s contract
• If you finish one part first (like a family room), we may assign a new base year value to that portion while the rest is still under construction.

• New construction made to improve accessibility for a person with a permanent disability may be excluded from reassessment.
• You must file Form BOE-63-A, the Claim for Disabled Accessibility Construction Exclusion. The property must be eligible for the Homeowners’ Exemption.

Active solar energy systems—those that produce electricity or heat for your home—are not assessed as new construction.

✅ Covered:

• Solar panels for electricity
• Solar systems for heating water

❌ Not covered:

• Solar pool or hot tub heaters

Exclusion deadline: This exclusion is valid through the 2025–26 tax year and sunsets on January 1, 2027.

If your new home included a solar system, you may receive a form titled "Initial Purchaser Claim for Solar Energy System New Construction Exclusion" from the developer.

• Mail the completed form to:
  Marin County Assessor-Recorder-County Clerk
  PO Box C, San Rafael, CA 94903
  Or drop it off at:
  3501 Civic Center Drive, Room 208, San Rafael, CA

Your builder can tell you the value of the system and any rebates or credits.

Call 415-473-7215 (CA Relay 711) . You can also visit our office Monday to Friday, 9 a.m. to 4 p.m.

If you received a Value Notice due to Proposition 8, it means the Assessor has reviewed your property and temporarily lowered its taxable value because the market value has dropped below the assessed value.

Passed in 1979, Proposition 8 allows a temporary reduction in your property’s assessed value when the market value on January 1 (the lien date) is less than your factored base year value (established under Proposition 13).

Each year, the Assessor must compare:

• Your property’s market value, and
• Your Proposition 13 factored base year value (adjusted annually for inflation)

The lower value is enrolled.

Proposition 13, passed in 1978, created the base year value system. Your base year value is set when:

• You buy the property
• You build new construction, or
• There is a change in ownership

Each year, this value may increase by no more than 2%, based on the inflation rate set by the state.

No. Once your property qualifies for a Proposition 8 reduction, the Assessor automatically reviews it each year. You'll receive a Property Assessment Value Notice in July with your updated value.

The annual review stops only when your market value is equal to or higher than your Proposition 13 factored base year value.

The law requires the Assessor to return your property to its original factored base year value once market conditions improve. Proposition 8 reductions are not permanent.

Your property will continue to be reviewed every year. If market values drop further, your assessment may go down again.

When market values rise, your temporary value may increase by more than 2% in one year. This is allowed because:

• The 2% limit applies only to base year values under Proposition 13
• Proposition 8 values are not considered base year values

Once your market value reaches or exceeds your adjusted base year value, the 2% limit applies again.

Example 1: Not eligible for reduction

• Assessed value: $650,000
• Market value: $740,000
  ✅ Market value is higher → No reduction

Example 2: May qualify

• Assessed value: $985,057
• Market value: $695,000
  ✅ Market value is lower → May qualify for Proposition 8

Example 3: No longer qualifies

• Assessed value: $985,057
• Market value: $1,050,000
  ❌ Market value is higher → Reduction removed

• Contact the appraiser listed on your notice
• You may also file an Assessment Appeal Application between July 2 and November 30
• The Assessment Appeals Board is an independent panel appointed by the Board of Supervisors
• Filing an appeal does not delay your tax payment—pay on time to avoid penalties

• Proposition 8 relief usually applies to recent purchases or construction
• Relief is based on the market value as of January 1 only
• Only the total assessed value is reviewed—not land and improvements separately
• Comparable sales must occur before April 1, and no later than 90 days after January 1
• A "Request for Assessment Review" is not the same as a formal appeal and is a separate process in a different department. 

• The Assessor determines property values
• The Department of Finance calculates and prepares tax bills
• The Tax Collector sends bills, receives payments, and distributes revenue

Need a copy of your bill or have payment questions?
Contact the Marin County Tax Collector:

• Phone: 415-473-6133 (CA Relay 711)
• Address: Civic Center, Room 202, San Rafael, CA
• Hours: Monday to Friday, 9 a.m. to 4:30 p.m. (closed holidays)
• Online tax payment

The annual tax bill is addressed to the owner of record on January 1 of that year.