Contra County Tax Collector Office: Pay Property Tax & Hours
If you searched for the Contra County Tax Collector, you are most likely looking for the official Contra Costa County Treasurer-Tax Collector in Martinez, California. This guide explains how to pay Contra Costa County property taxes online, find the Tax Collector office address, check walk-in hours, call the right phone number, look up a tax bill by APN, understand first and second installment due dates, avoid penalties, use mail or drop box payment, and know when to contact the Assessor instead of the Tax Collector.
The Contra County Tax Collector search usually means the Contra Costa County Treasurer-Tax Collector. The property tax office is at Finance Building, 625 Court Street, Room 100, Martinez, CA 94553. The mailing address is Contra Costa County Treasurer-Tax Collector, P.O. Box 631, Martinez, CA 94553. Walk-in hours are listed as Monday-Friday, 8:00 AM-5:00 PM; Call Center and Chat are listed as Monday-Friday, 8:00 AM-4:00 PM. For property tax help, call 925-608-9500 or use the official Tax Portal.
Official source: Contra Costa County Treasurer-Tax Collector and Contra Costa County Tax Portal.Contra County Tax Collector Means Contra Costa County Treasurer-Tax Collector
The official county name is Contra Costa County, California. Many users shorten the search to “Contra County Tax Collector,” but the office that bills and collects property taxes is the Contra Costa County Treasurer-Tax Collector.
When Is Your
Next Tax Deadline?
Select your state — see your exact deadline, live countdown, and whether you’re on time or already accruing penalties.
Use the Tax Collector when you need to pay a tax bill, view a tax bill, schedule a payment, check a posted payment, ask about paperless billing, mail a payment, use the drive-thru drop box, pay by phone, or ask about penalties and delinquency. Use the Assessor when your question is about assessed value, ownership records, property characteristics, exemptions, value appeals or parcel data.
Property Tax Penalty & Interest Calculator
State-specific penalty rates • Interest accrual • Tax lien deadline • Cost-of-waiting breakdown
| Original Tax Amount | $0.00 |
| Initial Penalty— | $0.00 |
| Monthly Interest— | $0.00 |
| Fixed Fees— | $0.00 |
| Total Due | $0.00 |
Daily Accrual Rate
Interest and penalties are adding this much to your balance every single day
Tax Lien Warning
| If You Pay On | Days Late | Penalty | Interest | Total Owed | Extra Cost |
|---|
Use the Tax Collector for payment
Pay taxes, view tax bill details, schedule payment, verify posting, request payment help, and ask about secured, unsecured or supplemental tax payment handling.
Open official Tax PortalUse the Assessor for value
Assessed value, property characteristics, ownership records, exemptions and assessment appeals are not fixed at the tax payment counter.
Open Contra Costa County AssessorUse the correct county
This page is for Contra Costa County, California. Do not confuse it with unrelated “Contra” search results, private payment ads or non-county websites.
Read payment safety checklistHow to Pay Contra Costa County Property Tax Online
The official Contra Costa County Tax Portal lets property owners look up property tax details, pay online, schedule payments, sign up for Paperless Billing and review tax history.
Before submitting a property tax payment, carefully confirm the Assessor Parcel Number, property address, tax year, installment, amount due and any penalties already added. Online systems can show pending payments or corrections, so if you are paying near a deadline or after delinquency, verify the balance before relying on an old bill.
Official source: Contra Costa County Tax Portal.Open the official Tax Portal
Start with the official Contra Costa County Treasurer-Tax Collector portal, not an ad or unofficial directory page. The portal is used for lookup, payment and tax history.
Go to official Tax PortalSearch by APN or property details
The county’s mail-payment guidance mentions entering the 10-digit APN to verify payment posting. If you do not know the APN, check your tax bill, deed, escrow papers, property records or Assessor tools.
Read official payment posting guidanceChoose the correct tax bill and installment
Contra Costa County secured property taxes use two installments. Make sure you are paying the first installment, second installment, both installments, a supplemental bill, or an unsecured bill correctly.
Open secured property tax due-date pageReview payment method and confirmation
Online, mail, phone, in-person and drop box payment methods can have different timing and proof requirements. Save the confirmation number or proof of mailing immediately.
View official ways to pay secured property taxesVerify posting after payment
Your canceled check can serve as a receipt for mailed payments, but the county also recommends verifying the posting of your tax payment online by account lookup.
Read pay-by-mail receipt noteSenior-friendly payment tip
If you are helping a parent, senior homeowner or out-of-county owner, read the APN and property address out loud before paying. Save the confirmation, write the payment date on the bill, and check the portal later to confirm the tax payment posted.
Contra Costa County Tax Collector Office Address, Mailing Address and Phone Number
The Contra Costa County Tax Collector office is located in the Finance Building at 625 Court Street, Room 100, Martinez, California. The mailing address uses P.O. Box 631 in Martinez.
Office / Walk-In Address
Use for in-person property tax service and payments
Mailing Address
Use for tax payments by mail
The official Tax Collector pages list the office at 625 Court Street, Room 100, Martinez, CA 94553; the mailing address as Contra Costa County Treasurer-Tax Collector, P.O. Box 631, Martinez, CA 94553; and the phone number as 925-608-9500.
Official source: Property Tax Information contact section.Contra Costa County Tax Collector Hours: Walk-In, Call Center and Chat
Contra Costa County lists walk-in hours as Monday through Friday, 8:00 AM to 5:00 PM. Call Center and Chat hours are listed Monday through Friday, 8:00 AM to 4:00 PM, except holidays.
Official source: Treasurer-Tax Collector contact page.Best time to call
Call earlier in the business day, especially near December 10 or April 10. Deadline days can create heavy phone, chat and in-person demand.
Before visiting
Bring your tax bill, APN, property address, payment method, prior receipt and any delinquent or supplemental notice.
Deadline caution
Do not wait until late afternoon on a delinquency date. In-person payments must meet office timing, and electronic systems can have availability limits.
| Need | Contact / route | Use this for |
|---|---|---|
| Property tax support | 925-608-9500 | Tax bill, due date, payment, phone payment options, copy of bill and customer service. |
| TTY | 711 | Relay service access. |
| Walk-in service | 625 Court Street, Room 100 | In-person payments, office help and same-day counter service during listed hours. |
| Official portal | Tax Portal | Lookup, pay online, schedule payments, paperless billing and payment history. |
Contra Costa County Property Tax Due Dates: December 10 and April 10
Secured property taxes in Contra Costa County are paid in two installments. The first installment is payable by November 1 and becomes delinquent after December 10. The second installment is payable by February 1 and becomes delinquent after April 10.
Official source: Secured Property Taxes due-date page.First installment
Payable by November 1 and delinquent after December 10. In-person payments must be made by 5:00 PM, and electronic payments are accepted until midnight on December 10 before penalty.
Second installment
Payable by February 1 and delinquent after April 10. The county lists a 10% penalty plus a $20 delinquent cost after the April deadline.
Weekend or holiday rule
If the delinquency date falls on a weekend or holiday, the delinquency date extends to the next business day. Always verify on the official page and your bill.
| Installment | Payable date | Delinquent after | Penalty note |
|---|---|---|---|
| First installment | November 1 | December 10 | 10% penalty after deadline. |
| Second installment | February 1 | April 10 | 10% penalty plus $20 delinquent cost after deadline. |
| Unsecured tax bills | Usually mailed before July 31 | Usually August 31 | If mailed after July 31, delinquent date may extend to the end of the month after issuance. |
Ways to Pay Contra Costa County Property Tax: Online, Mail, Phone, In Person and Drop Box
Contra Costa County gives taxpayers several ways to pay, but each method has timing, proof and deadline rules. Choose the method that best matches your deadline risk and need for confirmation.
Pay online
Use the official Tax Portal to view the bill, pay online, schedule payments, enroll in paperless billing and review tax history.
Open Tax PortalPay by mail
If paying without a coupon, send payment to County Tax Collector, P.O. Box 631, Martinez, CA 94553-0063. Include APN or tax bill details.
Read pay-by-mail rulesPay in person
The in-person office is Finance Building, 625 Court Street, Room 100, Martinez, CA 94553. Listed business hours are weekdays, 8:00 AM-5:00 PM.
Read pay-in-person pagePay by phone
Use the official phone route for property tax information or tax bill payment. Call 925-608-9500 and follow the county’s menu prompts for property tax payment, due dates, office hours or copy-of-bill needs.
Open official pay-by-phone pageDrive-thru payment drop box
Contra Costa County provides a drive-thru payment drop box option. Use the official drop box page to confirm location, allowed payment methods and timing before relying on it near a deadline.
Open drive-thru drop box pageContra Costa County Property Tax Lookup by APN, Bill or Property Details
Many people search “Contra Costa County property tax lookup,” “Contra County tax bill,” “Contra Costa property tax payment,” or “APN property tax search.” The practical goal is to find the correct tax bill before making a payment.
The safest search starting point is the official Tax Portal. Use your Assessor Parcel Number, property tax bill, address details, prior receipt or escrow paperwork. Before paying, compare the APN, property address, owner name, tax year, installment and balance.
Official source: Contra Costa County Tax Portal.| Search need | Best starting point | What to verify |
|---|---|---|
| I have a tax bill | Use APN or bill information in the Tax Portal. | APN, property address, tax year and installment. |
| I only know the address | Use Assessor/property records first, then Tax Portal. | Unit number, parcel, owner and legal description. |
| I paid by mail | Check bank clearing and tax portal posting. | Canceled check, APN and payment posting. |
| Mortgage company should pay | Check county account and escrow record. | Escrow disbursement date, amount and APN used. |
APN mistake warning
If you own more than one property, recently bought a home, inherited property, or have a supplemental bill, do not assume the first search result is correct. Match the APN and tax year carefully before payment.
Contra Costa County Property Tax by Mail: Address, Receipt and Posting Check
If submitting a tax payment without a coupon, Contra Costa County says to send it to County Tax Collector, P.O. Box 631, Martinez, CA 94553-0063.
The county’s pay-by-mail guidance says your canceled check is your receipt and recommends verifying that the check clears with your bank within a week. It also recommends verifying payment posting online by using Account Lookup and entering the 10-digit APN.
Official source: Contra Costa County Pay by Mail page.Mail payment checklist
- Use check, money order or accepted mailed payment method.
- Include the coupon when available.
- Write APN or tax bill details clearly.
- Use the official P.O. Box address.
- Keep a copy before mailing.
After mailing
- Watch for bank clearing.
- Use Account Lookup after posting time.
- Keep canceled check as receipt.
- Do not wait until last minute if mailing.
- Call if payment does not post as expected.
New Property Owners: Contra Costa County Tax Bill, Supplemental Bill and Escrow Questions
New property owners can be confused because the regular secured tax bill, supplemental tax bill, escrow account and prior-owner name may not all line up neatly.
Contra Costa County explains that the first installment is due November 1 and delinquent after December 10, while the second installment is due February 1 and delinquent after April 10. A new owner may not receive the annual tax bill, so checking the official Tax Portal is safer than waiting for mail.
Official source: New Property Owners page.Check closing documents
Look for APN, escrow tax prorations, prior-owner information and whether the mortgage company is expected to pay future installments.
Look up the tax bill online
Do not wait only for mail. Search the official Tax Portal and confirm if there is a current annual bill or supplemental bill.
Understand supplemental taxes
A supplemental tax bill can arrive separately after a change in ownership or new construction. It may not be paid by the mortgage company unless your servicer confirms it.
Unsecured Property Taxes, Supplemental Bills and Installment Plan Questions
Not every Contra Costa County tax bill is the standard secured annual property tax bill. Unsecured tax bills and supplemental bills can have different due dates, delinquency rules and payment timing.
Contra Costa County says most unsecured bills are mailed before July 31 and must be paid on or before August 31. If the bill is mailed after July 31, the delinquent date is extended to the end of the month following the bill’s issuance.
Official source: Contra Costa County unsecured tax bill due-date information.Unsecured property tax
Often applies to taxable property not secured by real property in the same way as a standard real estate tax bill. Read the bill carefully.
Supplemental tax bill
Usually connected to ownership changes or new construction. Do not assume your mortgage company automatically pays it.
Installment plan
Contra Costa County has official installment-plan information for certain delinquent property taxes. Check eligibility and deadlines directly with the county.
Open installment plan informationContra Costa County Tax Collector vs Assessor: Which Office Do You Need?
The Tax Collector collects and processes tax payments. The Assessor handles property value, ownership records, property characteristics and assessment-related questions.
| Your question | Correct office | Reason |
|---|---|---|
| I need to pay property tax or check payment posting. | Treasurer-Tax Collector | Payment, billing, due dates and collection service are Tax Collector tasks. |
| My assessed value seems too high. | Assessor | Assessed value is not changed through the payment portal. |
| I need a homeowner exemption or property record change. | Assessor | Exemptions and property records are assessment-side issues. |
| My bill is late or has penalties. | Treasurer-Tax Collector | Penalties, delinquency and payment plans are collection-side issues. |
Before You Pay: Contra Costa County Property Tax Safety Checklist
Use this checklist if you are paying close to a deadline, helping a senior homeowner, paying from outside California, or dealing with a new property purchase.
Website safety
- Use official Contra Costa County or Tax Portal links.
- Avoid ads that look like payment portals.
- Do not enter bank data on generic directory pages.
Account safety
- Match APN, address and tax year.
- Check first or second installment carefully.
- Look for supplemental or unsecured bills.
Proof safety
- Save online confirmation.
- Keep canceled check if mailed.
- Verify payment posting online.
Contra Costa County Tax Collector Videos: Pay, Read Your Bill and Understand Tax Types
Contra Costa County has Treasurer-Tax Collector video resources that help taxpayers understand secured property taxes, how to read a tax bill and ways to pay by mail, online or in person.
Official video source: Treasurer-Tax Collector Videos page.Ways to pay your property taxes
How to read your secured property tax bill
Contra Costa County Tax Collector Map: 625 Court Street, Martinez CA
Use the map for directions to the Contra Costa County Treasurer-Tax Collector office at the Finance Building, 625 Court Street, Room 100, Martinez, CA 94553.
Bring before visiting
- Tax bill or APN
- Property address
- Payment method accepted by the county
- Photo ID if needed
- Prior confirmation or notice if following up
Call before parking
- Confirm walk-in hours and holiday closures.
- Ask if your payment type is accepted.
- Ask if your issue is secured, unsecured, supplemental or delinquent.
- Do not wait until late afternoon on a delinquency date.
Official Contra Costa County Tax Collector Links
This article covers practical details, but final payment, current balance, payment method, hours, penalties and delinquency instructions should always be verified with official Contra Costa County resources.
More TaxCollectors.org Property Tax Guides
Use these related TaxCollectors.org guides to compare county tax collector payment workflows, office address formats, due-date rules, receipts and online payment systems.
Contra County Tax Collector FAQ
These answers cover the real search intent behind Contra County Tax Collector, Contra Costa property tax payment, office hours, address, phone number, APN lookup, due dates, penalties, mail payments and Assessor questions.
Who is the Contra County Tax Collector?
The correct official name is Contra Costa County Treasurer-Tax Collector. Many users shorten the search to Contra County Tax Collector, but the office serves Contra Costa County, California.
How do I pay Contra Costa County property taxes online?
Use the official Contra Costa County Tax Portal to look up property tax details, pay online, schedule payments, sign up for Paperless Billing and review tax history.
What is the Contra Costa County Tax Collector phone number?
The property tax contact phone number listed by Contra Costa County is 925-608-9500. TTY users can call 711.
Where is the Contra Costa County Tax Collector office?
The office is located at the Finance Building, 625 Court Street, Room 100, Martinez, CA 94553.
What are Contra Costa County Tax Collector hours?
Walk-in hours are listed as Monday through Friday, 8:00 AM to 5:00 PM. Call Center and Chat hours are listed as Monday through Friday, 8:00 AM to 4:00 PM, except holidays.
When are Contra Costa County property taxes due?
The first secured property tax installment is payable by November 1 and delinquent after December 10. The second installment is payable by February 1 and delinquent after April 10. If the delinquency date falls on a weekend or holiday, the date extends to the next business day.
What penalties apply after the deadline?
Contra Costa County says the first installment receives a 10% penalty after the December deadline. The second installment receives a 10% penalty plus a $20 delinquent cost after the April deadline.
Where do I mail Contra Costa County property tax payments?
If submitting a tax payment without a coupon, Contra Costa County says to send it to County Tax Collector, P.O. Box 631, Martinez, CA 94553-0063. Use the official page and your bill for final mailing instructions.
Can I pay Contra Costa County property taxes in person?
Yes. In-person payments are handled at the Finance Building, 625 Court Street, Room 100, Martinez, CA 94553, during listed weekday business hours.
Can I pay Contra Costa County property tax by phone?
Yes. Contra Costa County has a pay-by-phone information page and phone menu. Call 925-608-9500 and follow the prompts for property tax payment or tax bill information.
What if my mortgage company should pay my property taxes?
Check the official Tax Portal and your escrow statement. If payment does not show, ask the mortgage servicer for proof of disbursement, date, amount, APN and tracking details.
Who handles Contra Costa County assessed value questions?
The Contra Costa County Assessor handles assessed value, ownership records, property characteristics and assessment issues. The Treasurer-Tax Collector handles tax billing and payment collection.
Is TaxCollectors.org the official Contra Costa County website?
No. TaxCollectors.org is an independent informational guide. Always verify payment links, balances, deadlines, office hours, penalties and account instructions directly through official Contra Costa County sources.
Best Way to Use This Contra County Tax Collector Guide
Start with the official Contra Costa County Tax Portal if you need to pay or view a property tax bill. Search carefully, match the APN and property address, choose the correct installment or bill type, review payment timing, then save proof of payment.
Payment source: Official Contra Costa County Tax Portal.Use the Treasurer-Tax Collector for payment, receipt, due date, delinquency, mail, phone, drop box and tax bill questions. Use the Assessor for assessed value, ownership, property records, exemptions and value-related questions.
Official source: Treasurer-Tax Collector and Contra Costa County Assessor.Independent guide and official-source warning
This TaxCollectors.org page is an independent guide for people searching for Contra County Tax Collector, Contra Costa County Tax Collector, property tax payment, office hours, address, phone number, APN lookup, property tax bill, mail payment, drop box, due dates, penalties, supplemental tax bill and unsecured tax help. It is not the official Contra Costa County Treasurer-Tax Collector, Assessor, California government office, mortgage servicer, legal adviser or tax adviser.
Before paying, mailing documents, using a drop box, visiting the office, relying on a due date, disputing value, applying for relief, using an installment plan or handling delinquent taxes, verify current details directly with official Contra Costa County and California resources. Payment methods, processor rules, hours, holidays, mailing instructions, penalties, portal availability and account balances can change.