Choosing a Real Estate Agent in Port Costa, CA
By Matthew Martinez
Port Costa is a tiny unincorporated village on the Carquinez Strait in Contra Costa County, between Crockett and Martinez, with older homes on steep streets and very few sales in a typical year. Because Port Costa is not a city, permits and planning come from Contra Costa County, and a Port Costa agent should be able to find meaningful comparable sales, read an older home’s County permit history and flag hillside, drainage and fire zone questions.
This guide is published by Diamond Real Estate Group, one of the brokerages listed. Our broker is listed first; other agents are in alphabetical order. The order is not a ranking, and inclusion is not an endorsement.
How to use this agent guide
Start with the property questions below, then compare the publisher and five regional candidates. Public profiles and licensing records answer different questions: a license establishes regulatory status, while a profile describes claimed service areas. Neither establishes local sales experience, quality of service or suitability for your transaction. Some candidates name neighboring communities or the county rather than Port Costa itself; the profile evidence is shown explicitly. Interview more than one agent and ask for recent, relevant examples.
Port Costa housing in numbers
Port Costa is too small for reliable Census survey figures, and we did not find a current Census profile we could open, so we have left statistics out. With so few sales, ask any agent you interview which Port Costa, Crockett and Martinez sales they would use to price a home and why.
Port Costa settings: a hillside village on the strait
Port Costa’s homes are mostly older houses on steep, narrow streets above the waterfront, surrounded by open hillsides. That setting raises particular questions: older homes call for a close look at County permit records and inspections, steep lots bring drainage and slope questions, and the open hillsides make fire zone status and insurance important. Our guides to comparing Port Costa housing settings, older-home records and inspections and the local homeownership budget go into more detail. See also our Port Costa real estate guide.
Costs and rules specific to a Port Costa purchase
- Transfer tax. The Contra Costa County Clerk-Recorder charges the county documentary transfer tax at $0.55 per $500 of value. Port Costa is unincorporated, so no city transfer tax applies. On a $700,000 sale, the county tax is $770. Who pays is negotiable; confirm the figure on your escrow estimate.
- County jurisdiction. Building permits and planning approvals for Port Costa homes come from Contra Costa County; the County lists community plans on its Codes and Plans page. Compare the seller’s disclosures with County permit records; our older-home records guide covers the basics.
- Comparable sales. With very few local sales, an appraisal may rely on Crockett or Martinez sales; ask how the agent and appraiser will adjust for Port Costa’s setting.
- Condos and townhomes. If a property is part of an association, request the HOA budget, reserves and rules; our Port Costa condo and townhome costs guide explains what to review.
- Fire hazard zones and AB 38. Check whether the address sits in a State Fire Marshal Fire Hazard Severity Zone. In High and Very High zones, sellers may need to provide AB 38 defensible space documentation.
- Other hazards. The natural hazard disclosure report shows whether an address is in a mapped earthquake fault, landslide or flood zone.
Agent profiles to compare for a Port Costa transaction
Matthew Martinez, Diamond Real Estate Group (publisher)
Matthew Martinez is the Founder, CEO and Managing Broker of Diamond Real Estate Group, based in Sonoma County. Contact him to discuss representation for your specific property and location. Contact Matthew · Broker #01869679 · Diamond Group Estates Inc #02163490.
Five regional interview candidates
These profiles are drawn from the local and broader county research. The final column records the location evidence in each public profile; a nearby town or county reference does not establish completed transactions in Port Costa. Ask each candidate to demonstrate relevant experience before hiring them. This is an interview starting point, not a ranking or a claim that every agent specializes in this community.
| Agent / public profile | Brokerage as described by the profile | DRE record | Geographic evidence in the source profile |
|---|---|---|---|
| Jason Caskie | Coldwell Banker Realty | Salesperson #01347068 | Danville office |
| Kelly Copland | Coldwell Banker Realty | Salesperson #01376412 | Danville office |
| John Heywood | Coldwell Banker Realty | Salesperson #01765306 | Danville office |
| Malaika Hunt | Coldwell Banker Realty | Broker #01358675 | Walnut Creek office |
| Mike Kehrig | Coldwell Banker Realty | Salesperson #01823194 | Danville office |
For a wider comparison, read the county agent guide. Verify current license status and brokerage affiliation on the linked DRE record, and agree on representation terms in writing.
How to vet a Port Costa agent
- Ask which comparable sales they would use. With few Port Costa sales, ask how they choose and adjust Crockett or Martinez sales.
- Ask how they handle County permits. Ask how they check County permit records and planning rules for the parcel.
- Ask about slope, drainage and inspections. Ask which inspections they recommend for an older hillside home (foundation, drainage, sewer lateral, roof).
- Ask about fire zones and insurance. Ask how they handle AB 38 documentation and when they recommend getting insurance quotes.
- Ask for a net sheet. An estimate should show the county transfer tax, title and escrow costs and the commission terms you agreed to.
- Verify the license yourself. Look up the agent on the DRE site and confirm the responsible broker matches the brokerage they name.
Port Costa questions we hear
Is Port Costa a city?
No. Port Costa is an unincorporated community, so Contra Costa County handles planning, permits and most services.
Does Port Costa have a city transfer tax?
No. Port Costa sales carry the county documentary transfer tax of $0.55 per $500, according to the Contra Costa County Clerk-Recorder.
How should I use the regional candidate list?
Use it to arrange interviews. Ask each agent for recent transactions in this community, a sample pricing analysis and a plan for the property-specific checks described above. A county or neighboring-town profile is not proof of local transaction experience.
How do I check a Port Costa agent’s license?
Search the name or license number on the DRE public lookup. The record shows license type, status and responsible broker.
Sources & notes
- California DRE public license lookup
- Contra Costa County Clerk-Recorder: documentary transfer tax
- Contra Costa County: Codes and Plans (unincorporated communities)
- State Fire Marshal: Fire Hazard Severity Zones
- License records checked October 2026 on the California DRE public lookup. Last reviewed October 2026 by Matthew Martinez.
Related: Port Costa real estate guide · Port Costa home valuation · Contra Costa County agents guide · 20 tips for choosing a real estate agent
License-status update: the linked California DRE public records were checked November 2, 2026 and showed "Licensed." Public profile research retains the dates stated above. Names on DRE records may differ from public profile names; verify status and brokerage before selecting an agent.
