Site Assessment in San Jose, CA
A site assessment for an ADU in San Jose tells you whether your lot can legally and physically support the unit you want to build, before you spend a dollar on plans or permits. Most San Jose assessments run $450 to $950 depending on lot size, slope, and how deep into the city’s records we have to dig. Fielding ADU San Jose handles the whole thing for you, and the written report you get back is yours to keep whether you build with us or not.
Call (669) 201-3984 to schedule yours. A live person answers, day or night.
If you’re still figuring out whether you need this step, our ADU Design & Permitting in San Jose page walks through the full process from first sketch to final inspection. The site assessment is step one, and skipping it is how people end up with a set of plans the city rejects.
What a Site Assessment Actually Covers
Here’s the plain version. A site assessment answers four questions:
- Will the city approve an ADU here at all? San Jose has its own ADU ordinance, with rules on setbacks, lot coverage, parking, and height. We check your parcel against the current code, not the version someone quoted you last year.
- Where can the structure physically go? On a flat lot in Willow Glen, that’s a quick answer. On a sloped lot in the East Foothills, it takes real measurement. We flag retaining-wall costs and drainage early, not after groundbreaking.
- What’s underground? Sewer lateral depth, gas line location, electrical service capacity. If your panel’s at 100 amps and the ADU needs 200, that’s a $2,500 – $4,000 upgrade you want to know about now.
- What’s the realistic budget? We tie the site conditions to a build method. A Tuff Shed-style conversion on a flat pad costs less than a Plant Prefab unit that needs a foundation pinned into a hillside.
We deliver the assessment as a written report you can read in one sitting. No 40-page binder, no jargon fog. Just what’s possible, what it costs, and what’s in your way.
When You Need Site Assessment
Most people call us at one of four moments. If you’re in one of these spots, the assessment is the right next step:
- You’re not sure your lot qualifies. Maybe a neighbor said your backyard’s too small, or an old contractor said the setback rules killed the idea. San Jose’s ADU rules have changed more than once. What was true five years ago is often wrong today.
- You already have plans from someone else. Before you pay a drafter or an architect, pay for a site assessment. We regularly see plan sets in San Jose that ignore a sewer easement or a 15-foot rear setback and get bounced at the permit counter.
- You’re comparing build methods. Abodu, Boxabl, Plant Prefab, conventional stick-frame. The right answer depends on your lot, not a brochure. The assessment tells you which methods are actually viable on your parcel and what each one will really cost to site and connect.
- You got a quote that seems too low. A contractor who prices an ADU without walking the site is guessing. We walk first, then price. That’s the whole point.
Our Site Assessment Process
Here’s how it goes, step by step, no surprises:
- First call. You reach a live person at (669) 201-3984. We ask about your lot, your goals, and whether you have any existing surveys or plans. Then we schedule the visit.
- On-site walk. Reed Calloway or a senior Fielding ADU San Jose crew lead walks the property with you. We measure, photograph, check access for equipment, and note the grade, drainage, and adjacent structures.
- Records pull. We pull your parcel’s zoning, overlays, and permit history from the City of San Jose’s system. We look for easements, historic designations, and any open permits on the property.
- Utility and soil review. We check current service capacity at the panel, locate the sewer lateral and gas line where records allow, and assess soil and slope. If a geotech report is needed, we say so now, with a real cost number.
- Written report. You get a report with findings, a clear list of constraints, your viable build options, and a price range for each. We walk you through it in person or on the phone.
- Recommendation meeting. If you want to move forward, we tell you the next step and what it costs. If you don’t, you keep the report. No obligation, no follow-up pressure campaign.
Every assessment is done by someone who actually builds ADUs, not a sales rep. That’s the difference. When we tell you a setback is a problem, it’s because we’ve poured concrete against one.
Site Assessment Pricing in San Jose
Most San Jose site assessments from Fielding ADU Builders run $450 to $950. Here’s what moves the number:
| Factor | How it affects cost | Typical range |
|---|---|---|
| Standard flat lot, city utilities, clear records | Base assessment | $450 – $600 |
| Sloped lot requiring grade and drainage evaluation | Adds measurement and report time | $650 – $800 |
| Older home with incomplete permit history | Adds records research | $550 – $750 |
| Large lot, multiple possible ADU locations | Adds full-lot evaluation | $700 – $950 |
| Geotech soil report needed (hillside or fill) | Third-party cost, arranged separately | $1,800 – $3,200 |
If you proceed to ADU design and permitting with us, we credit the full assessment fee toward your design contract. That’s in writing, on the quote, before you sign anything.
And yes, the estimate for the assessment itself is free. You’ll get a fixed price before we schedule the visit. The number we give you is the number you pay, unless we hit something that legitimately expands scope mid-assessment, and then we stop and call you first. That’s the home standard we’ve operated under since 2006, and it applies to every assessment we do.
Key Takeaways
- A site assessment answers the four questions that kill ADU projects: legality, location, utilities, and budget.
- In San Jose, expect to pay $450 – $950 for a thorough assessment, with the fee credited back if you build with us.
- The assessment is yours to keep even if you never hire Fielding ADU San Jose for anything else.
- We assess with builder eyes, not sales eyes. What we report is what we’d build against.
- Written report, fixed price, no obligation. Call (669) 201-3984 to schedule.
Site Assessment vs. City Pre-Approval
One thing worth clearing up. The City of San Jose has pre-approved ADU plan programs, and people confuse those with a site assessment. They are not the same thing.
A pre-approved plan means the building design itself has already passed plan check. It saves time on the drawings. It does not tell you whether your specific lot can fit the structure, handle the drainage, or connect to your existing sewer line without a $12,000 trench cut through your driveway.
We’ve assessed lots in Almaden Valley where a pre-approved plan looked perfect on paper, then failed on site because the only viable ADU location sat directly over a storm drain easement. The homeowner spent $2,800 on a plan set they couldn’t use. A $600 site assessment would have caught it on day one.
If you’re considering a pre-approved plan or a prefab unit from Abodu or Dvele, do the site assessment first. It takes about two weeks from call to report, and it tells you which pre-approved or prefab options will actually work on your parcel.
What the Report Looks Like
You’ll get a written document, plain language, usually 6 to 12 pages depending on lot complexity. Sections include:
- Parcel summary – zoning district, lot dimensions, current use, and any overlays that apply.
- Setback and coverage analysis – where an ADU can legally sit relative to property lines and existing structures.
- Site constraint map – annotated photos and a simple overhead sketch showing viable build areas.
- Utility assessment – panel amperage, sewer lateral condition and depth, gas service location, and any upgrade requirements.
- Build method recommendation – whether your lot favors a conventional build with James Hardie siding, a Tuff Shed-style conversion, or a factory-built unit from a partner like Plant Prefab.
- Budget range – site prep, foundation, utility connections, and the structure itself, broken out so you can see where the money goes.
- Permit pathway – which city applications you’ll need, what they cost, and how long they typically run in San Jose right now.
We walk you through every section. You’ll know exactly what the city will push back on, because we’ve sat in those plan check meetings before.
Why San Jose Lots Are Tricky
San Jose has some specific quirks that make a site assessment non-negotiable here, more than in a lot of other Bay Area cities.
First, the city’s lot sizes vary wildly. You have 5,000-square-foot postwar lots in Cambrian, half-acre properties in the hills, and everything between. Setback and lot-coverage rules interact differently across those.
Second, San Jose is largely a flat valley floor with steep foothill edges. On the valley floor, drainage and high groundwater in low pockets near the Guadalupe River and Coyote Creek corridors affect foundation design. In the East Foothills and parts of Evergreen, slope stability and retaining requirements can add $15,000 to $40,000 in site work before a single wall goes up.
Third, the city’s sewer infrastructure is aging in many districts. A sewer lateral replacement under a street or driveway is one of the most underestimated costs in San Jose ADU building. The assessment flags this before it becomes a change order.
These are the things a generic contractor’s “free site visit” doesn’t check, because checking takes time and they’re trying to get to a contract. We take the time.
FAQs – Site Assessment
How much does a site assessment cost in San Jose?
A site assessment in San Jose typically costs $450 to $950 through Fielding ADU San Jose, depending on lot size, slope, and how much records research your parcel needs. If you move forward with us for design and permitting, we credit the full assessment fee toward your design contract. Call (669) 201-3984 and we’ll quote a fixed price on the phone.
Do I need a site assessment before building an ADU in San Jose?
You don’t legally need one, but you’d be making financial decisions blind without it. The City of San Jose won’t ask for a site assessment as part of the permit application, yet the assessment is what confirms your lot can fit an ADU before you pay for plans. We’ve seen too many San Jose homeowners lose money on plan sets that ignored a setback rule or an easement. The assessment protects the plan investment.
How long does a site assessment take?
From the day you call to the day you have the written report usually runs 10 to 14 days. The site visit itself takes an hour or two, and the rest is records pull, utility review, and the write-up. If a geotech report is required, that adds time depending on the soil engineer’s schedule, typically two to three weeks more.
Can you do a site assessment for a prefab or modular ADU?
Yes. We assess lots for owners considering Abodu, Boxabl, Dvele, Mighty Buildings, and other prefab and modular platforms, plus conventional builds. The assessment tells you whether your parcel can physically accept the unit you’re considering and what site prep, utility work, and foundation costs will look like. Call (669) 201-3984 and we’ll talk through your options on the first call.
What happens if the site assessment finds problems?
You get a clear list of what’s wrong, what it costs to fix, and whether it kills the project or just changes the budget. Some problems are fatal, like a sewer easement that leaves no legal build area. More often, the issues are manageable, like a $3,200 panel upgrade or a $6,000 retaining wall. You’ll know the real number before you commit to anything. That’s the point of the whole exercise.
Get Your Site Assessed
If you’re serious about building an ADU in San Jose, start with a site assessment. It costs a few hundred dollars, takes about two weeks, and gives you a written answer to the only question that matters right now: can this lot support what I want to build, and what will it actually cost?
Call (669) 201-3984. A live person answers, 24 hours a day, 7 days a week. We’ll schedule the visit, put the price in writing, and send a background-checked, uniformed crew lead to your property. No voicemail, no callback queue, no pressure.
Fielding ADU Builders has operated under the Garrison Standard since 2006. Written price first. Permitted work, by the book. A full year of written warranty behind everything we touch. If the work fails in that year, we come back and make it right at no charge. That includes the assessment.
Call (669) 201-3984 today and get the first straight answer you’ve had since you started looking into an ADU.
Written by Reed Calloway, Owner at Fielding ADU San Jose, serving San Jose.
