Plain-English answers for homeowners in Lancaster, Palmdale, and across the Antelope Valley who are building an ADU, an addition, or a new home — and just hit a requirement they didn't expect.
If the city, the county, or your architect just told you that you need a "soils report," a "geotechnical investigation," or a "perc test," you're not in trouble and your project isn't in danger. These are routine requirements, and homeowners across the Antelope Valley go through exactly this step every week.
What you need is someone to explain what's being asked, do the work properly, and give you a straight answer on the price. That's what we do. You'll deal directly with the engineer who signs your report — not a call center.
A soils report (also called a geotechnical report) is an engineer's study of the ground under your project. We drill or dig a few holes, describe the soil layers, test samples in a lab, and write a stamped report telling your designer how to build the foundation: how deep, how wide, and how to prepare the ground underneath. Think of it as a medical exam for your lot before the surgery.
More about soils reportsA percolation test measures how fast water soaks into your soil. It's only needed if your home uses (or will use) a septic system instead of a city sewer — common in Littlerock, Lake Los Angeles, Quartz Hill, and rural Lancaster and Palmdale. The result tells the county whether a septic system will work on your lot and how big it must be.
More about perc testingThe California Building Code makes the building department responsible for confirming your foundation is designed for the actual soil. In the Antelope Valley that's important: some desert soils settle suddenly when they get wet, and some clays swell. For septic systems, Public Health needs proof that wastewater will soak in safely rather than surface or reach groundwater. A soils report or perc test is that proof.
Before we arrive, we clear underground utilities through DigAlert (811). On the day, we mark the boring locations, drill or dig — usually with a small truck-mounted rig or hand equipment — log the soil, collect samples, and backfill the holes. For a typical house lot, we're there for part of a day. You usually don't need to be home; just make sure we can get through the gate.
Some projects need one, some need both. Here's the difference at a glance.
| Question | Perc test | Soils report |
|---|---|---|
| What it answers | Can the ground absorb wastewater from a septic system? | Can the ground safely support your building's foundation? |
| Who usually asks for it | LA County Public Health (Environmental Health), or Kern County in Rosamond | City of Lancaster, City of Palmdale, or LA County Building & Safety — or your architect/engineer |
| When you need it | Your property is not on a public sewer and you're building, adding bedrooms, or replacing a septic system | New homes, most detached ADUs, additions with new footings, grading, and retaining walls |
| What we do on site | Dig test holes or drill a deep boring where the septic system will go, pre-soak, and time how fast water drains | Drill borings or dig test pits where the building will go, log the soil, and collect samples for the lab |
| What you get | Stamped percolation report and, if needed, the septic system design | Stamped geotechnical report with foundation, grading, and seismic recommendations |
| Do I need both? | If you're building a new home or adding an ADU on a lot without sewer, you very likely need both. We can do them in the same site visit to save you time and money. | |
For a basic residential soils report in the Antelope Valley — a single-family home, addition, or ADU on a relatively flat lot — Southern California fees commonly fall somewhere around $2,500 to $5,000. The number moves with how many borings are needed, how deep they go, whether the site needs a drill rig or can be hand-sampled, what lab tests the soils call for, and whether the plan checker will want extra analysis (slopes, fill, or a nearby fault zone).
Titan's pricing for a typical residential report: [NEEDS FROM MOHAMMED: Titan's standard residential soils-report fee or range]. Every quote is a fixed written fee for a defined scope — send us the address and plans and we'll give you an exact number before any work starts.
Often, but not always. The California Building Code requires a geotechnical investigation for new foundations, but the building official can waive it for small, simple structures where the soil conditions are already known. In practice, whether you need one depends on where you are and what you're building:
If you're not sure, call us with the address. We'll tell you honestly whether you're likely to need one.
Usually not. We need clear access to the area where the work will be done, a gate code or unlocked gate if the lot is fenced, and the location of any known underground utilities, septic tanks, or irrigation lines. We call Underground Service Alert (DigAlert, 811) before any drilling. Most homeowners are at work while we're there; we'll call you when we arrive and before we leave.
Yes — that's the normal way we work. We'll coordinate directly with your architect, structural or civil engineer, and contractor, send them the report in the format they need, and answer plan-check comments that relate to the soils. You stay in the loop on every email, but you don't have to be the go-between.
Percolation testing costs depend on the type of test the county requires for your lot (shallow pit tests for a leach field, or a deep boring for a seepage pit), how many test locations are needed, and whether a drill rig is required. Across Southern California, a residential perc test and report commonly runs in the low-to-mid thousands of dollars. Titan's pricing: [NEEDS FROM MOHAMMED: Titan's standard residential perc-test fee or range]. We'll give you a fixed written quote once we know the lot and the system type.
Call or send us your address and what the city asked for. We'll tell you what's actually required — even if the answer is that you don't need us.
