Ask a longtime Larkspur homeowner why they haven't listed, and you'll usually get the same answer: the rate. They bought or refinanced when 30-year mortgages sat below 4%, and moving now means trading that payment for something built on California's average of 6.49% as of June 2026. That's real math, and it's kept a lot of equity parked in place.
But it's only half the story. The other half is a property tax basis that's been quietly compounding at 2% a year, sometimes for decades, while the house next door just sold to someone paying tax on today's price. Most owners assume that basis disappears the moment they sell. For a specific group of Larkspur homeowners, it doesn't have to. The rule that changes this math has been in effect since 2021, and based on how often the assumption still comes up, plenty of people haven't caught up to it.
Why So Little Comes on the Market
Look at what's actually listed in Larkspur right now and the scarcity isn't an impression, it's the number. A BAREIS MLS pull from early July 2026 showed seven active single-family listings and three pending sales in a city of roughly 12,800 people. The second quarter closed with 20 single-family sales total, a small enough sample that a couple of estate sales or a single hillside listing can swing the entire quarter's median.
That's exactly what happened. Larkspur's median single-family sale price rose 32.1% year over year in Q2 2026, while the average sale price actually slipped 2.2% over the same period, on the same 20 sales. That gap between median and average isn't a market getting more expensive across the board. It's a market where which 20 homes happened to sell changes the headline number more than any underlying shift in value.
The housing stock underneath those numbers tells its own story. The median year built across Q2 2026 activity was 1960, and most of Larkspur's single-family homes predate 1980. Most of that stock also carries no HOA and no Mello-Roos special tax, unlike newer Marin communities. A house this old, in a town like this, tends to have had the same owner for a long time. And a long ownership tenure under California's tax system means something specific: a tax bill that's fallen further and further behind market value with every year that passes.
The Rule That Changed in 2021
Here's where the assumption breaks down. Before 2021, if you wanted to sell a longtime home and carry your tax basis to a replacement property, you were boxed in. You could do it exactly once in your lifetime, and only into a county that had opted into reciprocity with your home county under Propositions 60 and 90. Miss that list and the whole benefit was gone.
Proposition 19 replaced that system. For homeowners 55 or older, severely disabled homeowners, and wildfire or disaster victims, the rules now look different:
- The transfer can happen up to three times over a lifetime, not once
- The replacement home can be anywhere in California, all 58 counties, with no reciprocity list to check
- You're no longer required to buy down. If your replacement home costs more, you keep your old basis and only pay tax on the difference in value
That last point is the one that surprises people most, because it means moving up doesn't automatically mean starting over on your tax bill.
The Math, Worked Out
Say a homeowner sells a long-held house for $900,000, carrying an old assessed value of $300,000. They buy a replacement home for $1.3 million. Here's how the assessor treats it under Prop 19:
- Take the market value difference between the new home and the old sale price: $1,300,000 minus $900,000 equals $400,000
- Add that difference to the original tax basis: $400,000 plus $300,000 equals $700,000
- The new home is assessed at $700,000, not $1.3 million
That's the blended formula. It doesn't erase the cost of moving up, but it means a $400,000 jump in home value doesn't translate into a $1,300,000 tax bill. For an owner who assumed selling meant resetting to full market value on whatever they bought next, that's a meaningfully different number to plan around.
What This Means If You're Actually Weighing a Move
Given how old Larkspur's housing stock is and how few listings turn over in any given quarter, there's a real population of owners here who likely qualify for this and haven't run the numbers. If you've owned your home long enough to remember when rates started with a 3, there's a decent chance your factored base year value is a fraction of what a buyer would pay for the same house today.
That gap matters more here than in newer parts of Marin, precisely because most Larkspur parcels skip the HOA dues and Mello-Roos assessments that inflate carrying costs elsewhere in the county. Your property tax bill has likely been the single most predictable, most locked-in number in your monthly budget. Prop 19 is the mechanism that lets you keep something close to that number even after you sell.
A few practical notes before anyone acts on this. The replacement home generally needs to be purchased within two years of selling the original for the transfer to apply in full, and the formal claim itself must be filed with the county assessor, using the correct BOE form, within the required window after that purchase. Marin's countywide transfer tax, separate from the ongoing property tax, is $1.10 per $1,000 of sale price and is customarily split between buyer and seller at closing. None of this is legal or tax advice. The Marin County Assessor-Recorder's office publishes the current eligibility rules and required forms, and a CPA or estate attorney should confirm how this applies to your specific situation before you list anything.
A Few Questions Worth Asking
Does the replacement home have to stay in Marin? No. Prop 19 dropped the old county-reciprocity requirement entirely. You can carry your Larkspur tax basis to a replacement home anywhere in California.
What if I'm not planning to downsize, just relocate closer to family? The benefit applies regardless of whether the replacement home is smaller, larger, or simply in a different part of the state. The blended-value formula applies either way.
Can I use this more than once? Homeowners 55 or older can use the base year transfer up to three times over a lifetime. Disaster victims can use it without that limit.
Two forces have kept Larkspur's inventory this thin: a mortgage rate that made staying cheaper than moving, and a tax assumption that made selling feel more expensive than it has to be. The first one is a market condition. The second is a rule that changed years ago and simply hasn't caught up with everyone's mental math yet.
If you're sitting on a longtime Larkspur home and trying to figure out what actually pencils out, that's exactly the kind of conversation worth having before you list, not after. Melissa Crawford has spent more than 20 years working through this math with Marin homeowners one property at a time. Let's Connect.
