It's generally solid for state-level ADU rules. Double-check anything local or hazard-related against your city or a parcel-level tool, since overlays vary block to block.

Is there a free ADU feasibility tool?

Yes. Symbium's core checks are free statewide, and BackyardCheck's address check is free for Los Angeles with an optional $99 cost/ROI report.

Does BackyardCheck cover cities outside Los Angeles?

Not yet. It's deliberately deep on the City of Los Angeles first using the city's own parcel and zoning data. If you need another city today, Symbium has wider coverage.

Symbium alternatives — what Reddit actually recommends

People on Reddit like Symbium for statewide coverage but reach for other tools when they want a faster, more honest yes/no on a specific lot. The alternatives that come up most: BackyardCheck for an LA-specific verdict with cost and rent ROI, ADU Scale and Site Plan Creator for design and site layout, and simply calling the city for the authoritative answer. No single tool wins for everyone — pick by your city and how deep you need to go.

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The alternatives, with honest pros and cons

Tool	Pros	Cons
Symbium	Free; statewide California coverage; sketch an ADU and see rough placement	Can read one-size-fits-all on overlay/hazard lots; nudges toward its vendor marketplace
BackyardCheck	Reads your actual LA parcel (zoning, setbacks, hillside/fire/flood/coastal); flags "needs review"; honest cost/ROI	LA-first — expanding city by city, so other metros aren't live yet
ADU Scale / Site Plan Creator	Useful once feasibility is confirmed and you want to lay out the unit	Less focused on the upfront "can I even build" question
Calling the city	Authoritative; free	Slow; hold times; you need to know what to ask

Comparison reflects publicly available information and may change. Symbium is a trademark of its respective owner; BackyardCheck is not affiliated with Symbium.

The verdict

Start with Symbium for a statewide overview. If you're in Los Angeles and want a straight feasibility answer plus real cost and rent numbers, BackyardCheck is the more direct alternative — it reads your specific lot and tells you when it isn't sure rather than overpromising.

Comparing tools head to head? See BackyardCheck vs. Symbium and BackyardCheck vs. ADUscale.

Symbium alternatives: common questions

It depends on your city. Symbium has the widest California coverage. If you're in Los Angeles and want a fast, honest yes/no plus real cost and rent ROI, BackyardCheck reads your specific parcel and flags ambiguous lots instead of guessing. Both have free checks.

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