Builder Rafael Pozas ends the episode with a stated mission: to get the realtors to walk away "looking at properties in a different way." The idea is simple — anyone buying a house in California today should know whether the lot can take an ADU, even without plans to build one.

Why this belongs in choosing the house

Rafael pictures the scene: the buyer closes the deal and, a week later, finds out what an ADU is and that the lot they chose wouldn't allow one. Even if they don't want to build, he argues, they should have had the right to choose a house where it was possible, because it widens the property's options down the road.

One of the realtors adds: it's a safety plan. "I bought this house, I paid this price, but if things get tight, I can build a unit and solve my problem." And, when it's time to sell, the next buyer may want to build — which makes the property more attractive.

The realtors say that, in general, a buyer with that intention says so up front: they want a house with room to build later. Since they don't have a contractor's technical knowledge, they steer the client toward talking to a builder — and that's where Rafael proposes working together: the agent sends the address and the dimensions, and a basic feasibility read comes back fast, in time to close the purchase.

Feasibility before the architect

In the episode, one of the realtors sums up the logic Rafael argues for: normally, people look for an architect first to design the ADU. But the architect is focused on the design and doesn't always know what is feasible and economical to build on that particular lot. So the recommendation is to flip the order: first, the feasibility study with someone who knows construction; then, the design.

Rafael describes that study as a "game of chess": lot dimensions (even from Google Earth, at first), setbacks, distance from the main house, how much can be built in total and how to split it between house and unit according to demand in the area.

What to evaluate before the offer

• Zoning: is the lot residential? Is it in an area with restrictions (historic, coastal, fire hazard)?
• Area and shape: free space accounting for setbacks of up to 4 feet from the property lines and the distance from the house.
• Slope: a flat lot is cheaper; a sloped one can require retaining walls and a sewage pump.
• Access: how do materials, the crew and, later, the tenant get in? Is there a side entrance or an alley?
• Utility connections: location of the sewer line, capacity of the electrical panel, water and gas meters.
• Homeowners association (HOA): the law limits HOAs' power to ban ADUs on single-family homes, but rules on appearance and prior approval can exist.
• Permit history: what of the current house was permitted.

In California, the buyer normally has a contingency period to investigate the property. That is the moment to check with the city and run the feasibility study — before giving up the right to walk away.

Does a main house in bad shape get in the way?

One of the realtors brings two real client cases: one who wanted a lot with room for two houses, not caring about the front house, which he planned to demolish; another, of elderly parents living in a house in terrible condition who wanted to build the ADU out back. Does the condition of the main house block approval?

According to Rafael, no. Remodeling the house and building the ADU can even go forward together, with separate permits. His suggestion for anyone with people living there: build the ADU first, move the residents into it temporarily and then remodel the main house.

And the unpermitted parts of the house?

What Rafael runs into often is a different situation: parts of the house built without a permit, and the owner's fear of drawing the city's attention by applying for the ADU permit.

His guidance is to evaluate case by case. If the irregular item is simple — an old patio cover, for example —, demolish it first and do the design without it, since officially it doesn't exist. If it's something bigger, it's worth considering folding the legalization into the process, because, to add value to the property, ideally everything should be on paper.

Rafael reports, from his experience, that the city inspector tends to stick to what is in the permit under review — a different situation from a complaint by a neighbor annoyed with the work, which can lead to a broader inspection. That does not eliminate the risk, however: unpermitted work can trigger a demand for legalization, a fine or demolition at any time, and safety problems should be fixed regardless.

An old unpermitted ADU: the AB 2533 route

For anyone buying a house with a unit out back built without a permit, the law has shifted in favor of legalization. AB 2533, in effect since January 1, 2025, establishes that the city cannot deny the permit for an ADU or Junior ADU built without permission before January 1, 2020 solely because it violates building standards or the local ADU ordinance — provided the unit is not a threat to health and safety, under the terms of the Health and Safety Code (section 17920.3). The law also limits the charging of certain fees and penalties in those cases.

That does not make legalization automatic or free: it may be necessary to fix safety items, pay permit fees and go through inspection. But it changes the risk analysis for anyone buying.

Selling with the plans approved

One last point Rafael raises: someone about to sell who never built can develop and get the ADU plans approved and put the house on the market with a permit ready to execute. For the buyer, that removes months of uncertainty — and it gives the property liquidity.

This text is for informational purposes and does not replace legal or technical advice, or a consultation with the city's planning department.

Sources and verification

• AB 2533 (2024) — legalization of ADUs and JADUs built without a permit before January 1, 2020, in effect since January 1, 2025 (guidance from San Mateo and Santa Cruz counties and from ABAG).
• California Health and Safety Code, section 17920.3 — conditions that make a building substandard.
• California Civil Code, section 4751 — limits on ADU prohibitions by homeowners associations (HOAs).
• California Department of Housing and Community Development (HCD) — Accessory Dwelling Unit Handbook (most recent update) and Government Code, sections 66310 to 66342.
• Transcript of episode 9 of the Cadê Moradia podcast (April 2026), with the show's realtors and builder Rafael Pozas.

This topic comes from the full episode — watch it:

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