My neighbor came over last weekend pretty shaken by her first full quote. She's in her late 60s, planning a detached 650 sq ft adu in the backyard for her daughter's family to use part time. The number landed at $340,000 fully loaded When she sat down with the builder and went line by line, most of it actually made sense. Site prep, soil report, sewer lateral and grading came to almost $45,000 on their own. School district fees, permits and utility hookups added another chunk she hadn't budgeted for at all. Because her lot backs up to a canyon, the foundation spec bumped up significantly too. The thing that bugs me is how many online calculators still show $180k to $220k for projects around here. For anyone currently pricing out the cost of building an adu in san diego, what are finalized quotes looking like for you in 2026, not the early ballpark numbers?
r/AccessoryDwellings
What ADUs actually cost around West LA right now
I’ve been noticing that ADU costs around West LA still surprise people more than almost anything else.
Especially in places like Mar Vista, Rancho Park, Beverlywood, Mid City, Santa Monica, and Culver City.
Rough ranges I keep seeing:
Garage conversion:
$175k–$250k
Detached ADU:
$280k–$400k
Two-story ADU:
$375k–$550k+
The big swings usually come from the boring stuff.
Electrical upgrades.
Sewer location.
Foundation work.
Fire-rated walls.
Access to the back of the lot.
How far utilities need to run.
What looks workable on paper may not fit cleanly on the actual lot.
From what I’ve seen, the biggest difference is early property review.
The practical takeaway is simple: square footage matters, but the lot conditions often decide the real budget.
Curious if other homeowners, designers, or builders around West LA are seeing similar numbers.
Garage conversion floor plan advice
I’m converting my garage to a JADU for rental income. In the planning stage at the moment and I want to achieve the best balance between staying in budget but also giving the future tenant a space that feels homely.
The attached picture shows the current proposed floor plan by the architect. The WH is existing so would prefer not to move it. The bathroom is there as a lot of the existing plumbing for a garage sink is there.
The kitchen sink will be moved to the top wall next to the stacked washer dryer so all the plumbing stays in the top wall.
My issue is that there seems to be a lot of wasted space in the middle. The kitchen seems like it comes too far down into the seating area. Also would like to have some storage space/closet.
Can anyone suggest any alternatives or improvements to the current proposed design? Appreciate the input.
Where building ADU can go wrong
Most homeowners think building an ADU is expensive because of construction costs.
That’s not actually what destroys the budget.
The real killer is bad planning before construction even starts.
I’ve seen people lose:
4–8 months in permitting
tens of thousands on redesigns
huge amounts on utility relocation
money fixing grading/drainage mistakes that should’ve been caught on day one
And the craziest part?
A lot of contractors still bid ADUs without properly analyzing:
setback limitations
sewer connection distance
electrical capacity
soil conditions
access logistics
parking impact
foundation compatibility
That’s why two identical-looking ADUs can have completely different final costs.
One finishes smoothly.
The other turns into a financial bleeding machine.
The homeowners usually blame “construction pricing”…
…but most of the damage started long before the first shovel touched the ground.
ADUs are becoming one of the smartest investments in California right now — but only when the planning phase is done correctly.
Most expensive mistakes in construction happen in silence before construction even begins.
Just found out from my town that they don't allow these! Anyone ever run into this and any other suggestions?
Rancho Cucamonga First Pre-approved ADU Plan: What It Means for California Homeowners
We recently finished Rancho Cucamonga’s first completed pre-approved ADU project.
Permit time: about 2 months
Build time: 5 months
We’re doing a short livestream about the project and sharing the full process from planning to construction.
Our own ADU Specialist, Janine, will walk through the project step by step:
- How a pre-approved plan helped reduce permit time from around 6 months to 2
- What California’s 2026 ADU law changes could mean for homeowners
- What a real 5-month ADU build looks like from start to finish
We’ll also cover:
- How the Rancho Cucamonga pre-approved ADU program works
- Actual city review timelines
- Why the owner changed floor plans during design
- Accessibility upgrades added for everyday living
If you’ve been thinking about building an ADU in California, feel free to join us.
LinkedIn: Apex Homes (LinkedIn) Live Stream Sign-up link
Youtube: Apex Homes (Youtube Link)
Hey all, I'm in the initial phase of scoping out ADU's. I'm looking to build something around 1000 sq feet that is super wheelchair accessible, next to my house. My sister recently passed away from cancer and my mom is 77 and now living alone, want to give her something nice that she can grow old(er) into. The only think I really want is a big bathroom with grab bars around the toilet and a no step shower. Wondering how hard that would realistically be to plan out and build. In Northern IL, on septic and well. Zoning is having a vote to allow ADU's at the end of summer, I already talked to the zoning board. Im hoping they vote yes and I can get this started.
Anyone got any build plans for wheelchair accessible ADU's?
Private Permit Reviewers needed for hire
Hey guys! With AB 253, we are now allowed to use a Private Permit Reviewer to handle the permits if the municipality take longer than 30 days on their dashboards (which is pretty much everyone). The problem is this industry has never existed in California before. Are there any licensed architects or engineers interested, even as a side hustle? Let me know because I have some companies that would set up such a business and handle the insurance and bonding if they have the people to do the jobs.
Looking to get an a good ballpark of what I should expect for a 749 sq fr ADU in San Diego. Bay park area. ADU is planned to be 749ft, 2 bed 2 bath . Electric and water and sewer .
I’ve been noticing that ADUs around West LA don’t really run like normal home additions, but they also don’t feel like simple backyard projects either.
The structure may be small.
But the property issues can be big.
Especially in places like Mar Vista, Rancho Park, Beverlywood, Mid City, Cheviot Hills, Culver City, Santa Monica, and nearby LA neighborhoods.
Setbacks.
Access.
Utilities.
Fire clearance.
Parking.
Privacy.
Drainage.
Older lots.
Tight driveways.
City-by-city review differences.
That middle ground creates its own planning category.
From what I’ve seen, the biggest difference is early property review.
What fits on paper may not fit cleanly on the actual lot.
A standard ADU plan may look approved, but the site still decides a lot.
Without checking the property early, the project can get blurry fast.
Curious if other West LA / Culver City / Santa Monica homeowners, designers, or builders are seeing the same thing.
Do you think ADUs in older Westside neighborhoods need their own early planning system before design starts?