Step 09 · Consider letting
A large share of ADUs are never let to a stranger at market rent. That finding should shape the expectations you build the project on.
The short answer
Most ADUs can be let long-term, subject to local rules. In California a rental created under the by-right provisions must be for a term longer than 30 days (Gov. Code § 66323), which rules out short-term letting under that route.
Rent control and short-term rental rules are separate local questions. Actual rental income depends on your local market.
We do not publish projected returns. Rental income depends on local rent, vacancy, your construction cost, financing, operating costs, taxes and insurance — and any general figure would be misleading.
What moves it
Four separate bodies of rule, each with its own answer:
Gov. Code § 66323 requires terms longer than 30 days for ADUs created under the by-right section; § 66315 lets an agency impose the same floor generally.
A separate local regime. Many cities regulate or prohibit letting under 30 days regardless of ADU law.
Whether a newly built unit is exempt is a question of statute and date, not of intuition. See the research below.
Ordinary landlord–tenant obligations apply. An ADU in your garden is still a tenancy.
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ADU occupancy is the finding most likely to change how you plan. A substantial share of ADUs house family members, or are used by the owner, rather than being let at market rent to a stranger.
If your budget depends on market rent from day one, that assumption deserves testing before you commit. The occupancy evidence is on the research page below, with its sources and limits.
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We will not tell you what your ADU will rent for. We do not hold a rent dataset for your street, and any figure we produced would be a guess wearing a decimal point.
Our rent estimator asks you to look up HUD Fair Market Rent for your area — a published, dated, official figure — and work from that. It is a deliberate design decision, and it is why the tool asks you to do a step other sites would fake for you.
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Insurance changes when a second dwelling is added and when it is let; our insurance research covers what actually changes. Property tax treatment changes too, and the ADU is typically assessed as new construction without reassessing the whole property.
Vacancy, maintenance, turnover and management all come out of gross rent before anything reaches you.
Go deeper
ResearchOriginal analysis
StatisticsSourced figures
ToolsRun your numbers
Often not. In California a rental created under the by-right provisions of Gov. Code § 66323 must be for a term longer than 30 days, and many cities separately regulate or prohibit short-term letting. Check both your ADU’s approval route and your city’s short-term rental ordinance.
That depends on your local market and we do not hold that data for your street. Our rent estimator works from HUD Fair Market Rent, which you look up for your own area — an official, dated figure rather than an invented one.
It depends on the statute and the unit’s construction date, and it is not safe to assume. Our rent control research sets out how the exemptions are structured and what dates govern.
Plan your project
Three short steps: the ADU you want, your home, and how to reach you. Nothing goes to a contractor unless you agree.
A straight answer: our ADU professional matching is still being built, so this is not a quote service, and we cannot tell you whether your lot qualifies. We can help you work out which questions to ask and what a thorough proposal should contain. Your planning department decides what is permitted at your address.
Get ADU Options
Tell us about the ADU you are planning and where you are. We will follow up about connecting you with contractors serving your area.