How Long Does a Soils Report Take in Southern California?

The short answer: 2–4 weeks for most projects

For a typical single-family residential project in Southern California — new home, ADU, addition, retaining wall — a soils report takes 2 to 4 weeks from the day we mobilize to the day you have a stamped report in hand.

That said, "typical" covers a wide range. We've turned around reports in 10 days for straightforward flat lots. We've also had reports take 8 weeks on complex hillside sites with deep borings, expansive soil conditions, and slope stability analysis. Your timeline depends on what's actually happening underground, not just what's on the surface.

Here's how each phase breaks down — and where time actually gets spent.

Phase 1: Field Work (1–3 days)

The field phase is the fastest part of the process. For a standard residential project, our driller is typically on site for 1 to 2 days. We drill borings (usually 2–4 for a single home, more for larger sites), log the soil, take samples, and wrap up.

What can stretch field time:

• Difficult access: Properties on steep slopes, with locked gates, or with overhead utility conflicts require more setup time and sometimes specialized drilling equipment.
• Deep borings: Most residential borings go to 25–35 feet. Hillside projects, commercial sites, or sites with deep fill can require 50–75 feet or more — which takes significantly longer per boring.
• Hard rock: Drilling through rock is slower and may require a different drill type. Some San Diego hillside areas hit metavolcanic rock at 10–15 feet.
• Utility conflicts: We call DigAlert before every job, but hand-digging around utilities adds time.

Scheduling the driller is often the longest wait in this phase. In Southern California, reputable drillers have 1–2 week backlogs during busy seasons (spring and fall). We maintain relationships with multiple drillers to minimize this.

Phase 2: Laboratory Testing (1–2 weeks)

Once the field samples come back, they go to the lab. Standard tests for a residential soils report include moisture content and dry density, grain size analysis, Atterberg limits (plasticity), expansion index (required by California building code), and maximum dry density and optimum moisture (Proctor test, for compaction specs).

Most labs in Southern California turn around standard residential testing in 5–10 business days. Specialty tests — like direct shear for slope stability or consolidation tests for settlement analysis — can add another week.

We can't write final recommendations until lab results are in. This is typically the gating step for most residential reports.

Working on a project in Southern California? We can handle the engineering.

Phase 3: Engineering Analysis and Report Writing (3–7 days)

With field data and lab results in hand, the geotechnical engineer analyzes the findings and writes the report. For a straightforward residential project, this typically takes 3 to 5 business days.

More complex projects — slope stability analysis, liquefaction evaluation with detailed shear wave velocity data, settlement analysis for structures sensitive to differential movement — take longer. A full hillside analysis with limit equilibrium modeling can take 1 to 2 weeks just for the engineering.

The report then goes through internal review and stamping by the licensed PE/GE of record. We don't skip this step, even on rush jobs.

Phase 4: Plan Check Review (Variable — not our timeline)

Once we hand you the stamped report, the clock switches to the building department. This is the phase that surprises most clients.

In San Diego, first-round plan check for a soils report currently runs 3–6 weeks. Orange County cities vary widely: Irvine is fast (often 2–3 weeks), while some smaller cities can take 6–8 weeks. LA County unincorporated runs 4–8 weeks.

Cities with over-the-counter (OTC) review for simple residential projects can move much faster — sometimes same-day or same-week. Check with your city's building department for current wait times.

Plan check comments on the soils report are common. The most frequent: insufficient boring depth, missing expansion index, slope stability not addressed, or foundation recommendations not sufficiently detailed for the plan checker's questions. We respond to these quickly — typically within 3–5 business days of receiving comments.

How to speed up your soils report

If you're on a tight timeline, here's what actually helps:

Start early. The soils report should be one of the first things you commission — not something you scramble for when plan check requests it. Most architects want the report before finalizing foundation design anyway.

Have site access ready. We need clear access to boring locations with no vehicles, construction, or landscaping in the way. Locked gates, aggressive dogs, and landscapers who "didn't know we were coming" are real delays.

Tell us if it's a rush. We can expedite lab testing (most labs offer rush service for a fee) and prioritize report writing for time-sensitive projects. We can't always do it, but we'll tell you up front if we can.

Don't reuse an old report. If a report exists from a previous owner or a different project on the site, it may or may not be usable. Bring it to us first — we'll tell you if it covers your scope or if a new investigation is needed. Using an outdated report that the plan checker rejects costs far more time than starting fresh.

Bottom line

Budget 3 to 5 weeks from authorization to stamped report for a typical Southern California residential project. Add time for complex sites, deep borings, or specialty testing. Then budget separately for building department plan check — that's a parallel process we can help you navigate but can't control.

If you're getting started on a project, contact us now and we'll give you a realistic timeline specific to your site and jurisdiction.

Related Service

Soils Reports & Geotechnical Investigation

We handle this for projects across Southern California.