Zoning · floor area · the market
In Atherton you are buying an acre first.
Atherton zones for one house per acre, allows each to grow to a set share of its lot, and has no commercial land at all. Every Eichler here is priced against what the same acre would fetch empty.
On level ground
Of the lot
Anywhere in town
The rules
What the code allows.
The minimum lot in Atherton depends on slope: one acre, 175 feet wide, on ground with an average cross slope under 20 per cent; two acres at 20 to 35 per cent; five acres beyond that.
On a lot of an acre or more, the house may cover 18 per cent of the lot in floor area. On a smaller lot the allowance is the lot area times 0.163, plus 726 square feet. Upper floors are held to 7.5 per cent of the lot. Front and rear yards are 60 feet. The main building may rise 30 feet.
There is no commercial zoning anywhere in the town — no shops, no restaurants, no grocery.
- Minimum lot, level ground
- 1 acre · 175 ft wide
- Floor area, lots ≥ 1 acre
- 18% of lot
- Floor area, smaller lots
- Lot × 0.163 + 726
- Upper floors
- ≤ 7.5% of lot
- Front and rear yards
- 60 ft
- Height, main building
- 30 ft
Source: Atherton Municipal Code §§ 16.24.050 and 17.32.040.
One house, measured
The room a single Eichler leaves.
Apply those rules to 19 Irving Avenue. Its lot is 39,123 square feet — just under an acre — so the smaller-lot formula governs, and the code would allow about 7,100 square feet. The house is 3,700.
That unbuilt half is the pressure every Atherton Eichler is under. It is also, precisely, the thing a preservation buyer is choosing not to use.
The market
Figures, dated and attributed.
Atherton has spent most of the past decade as the most expensive ZIP code in the United States. PropertyShark put the median sale price in 94027 at $8,333,000 for the first nine months of 2025, second in the nation. By the first half of 2026 it reported the median up about 20 per cent, to almost $10 million, and the title back.
Zillow’s Home Value Index for Atherton stood at $8,521,138 on 31 August 2026 — a modelled index across all homes, not a median of sales.
We do not quote Redfin figures on this site; its terms bar republishing them. And we do not blend these numbers, because they measure different things over different windows.
The land
What an acre fetches empty.
In October 2025 a 1.157-acre lot at 123 Stockbridge Avenue sold for $9.5 million on the strength of the land; the listing agent said the house “had no significant value.” In November a lot of just under an acre at 57 Fairview Avenue closed at $10.7 million. Replacement construction runs $2,200 to $2,600 a square foot, so a new estate is often a $10 million lot carrying tens of millions of building.
For comparison, and with the dates side by side: we listed Joe Eichler’s own house, on 0.90 acre, at $6,385,000 in March 2024. The land sales above are from late 2025, eighteen months later, in a market that rose sharply in between. They are not contemporaneous, and we do not present them as if they were.
The honest part
Architecture is not priced here.
We looked for any source that measures a premium for architectural significance in Atherton. We found none, and the evidence we do have points the other way. An Eichler here sells to one of two buyers: someone who wants the acre, or someone who wants the house. The whole job is finding the second one.
Questions we get asked
The ones that come up.
- What is the median home price in Atherton?
- It depends on the source and the window. PropertyShark put it at $8,333,000 for January to September 2025 and at almost $10 million for the first half of 2026. We cite each with its date rather than average them.
- Could I build a larger house on an Eichler lot in Atherton?
- Usually, yes. On a lot of an acre or more the code allows floor area of 18 per cent of the lot, and most Eichlers use a fraction of that. Whether you should is a different question.
- Why don't you publish a median for Atherton Eichlers specifically?
- There are too few of them, and they trade too rarely, for any median to mean anything.
What we can do for you
Things worth asking us for.
If you are trying to buy one
Seven are standing. They almost never sell.
An Atherton Eichler comes up once in years, and when one does the buyer who gets it is almost always the one who was already known to the seller’s agent. Tell us what you are looking for and we will tell you, honestly, whether it exists.
Talk to us
What yours is worth, as a house.
An Atherton Eichler has two prices: what the acre fetches, and what the house is worth to someone who wants it. We will tell you both, and show you how we got there.
Where to go next
Read these three.
The rest of the story