A percolation test
Times how fast water drains out of a shallow hole to estimate an absorption rate. It's a single number — and on rocky, layered mountain soil, that number can hide what's really underground.
Soil & Perc Testing
Soil & perc testing for septic systems in Colorado
Before you can build a septic system, your ground has to be evaluated. Most people call it a "perc test." On Colorado's mountain lots, what actually designs a system is a soil profile pit test — and that's what we do, start to finish, from the feasibility visit through the engineered report.
Licensed Soil EvaluationReg 43 CompliantTwo Profile PitsEngineered Reports
A soil test is the cheapest way to find out — before you spend — whether a lot can be built on at all.
Effective septic systems protect your family and the environment by treating wastewater on-site, where there's no municipal sewer. But a system is only as good as the ground under it. Testing tells the engineer how your soil absorbs and filters water, how deep the bedrock and water table sit, and what kind of system — if any — your lot will actually support. Skip it or get it wrong, and you're re-digging a drainfield in frozen ground a few winters later.
The problem with a plain percolation test on mountain ground is that it hands you one number. Decomposed granite, clay lenses, and shallow bedrock don't show up in a single drain rate — but they absolutely show up in a septic system that fails. So we test the way the state's engineers design from.
Perc test vs. soil profile pit test
A soil profile pit test
Digs deep test pits so a licensed evaluator can read the actual soil horizons — texture, structure, depth to bedrock and groundwater, restrictive layers. It's what an engineer needs to design a system that lasts. It's what we do.
How testing works with us
1
PlanSite Feasibility Report
We visit the lot and check setbacks, slope, a hands-on soil read, and county/health-department code — and flag anything that could constrain a system before you spend on testing. You get a written report and a plan, usually within three business days.
$2,000credited toward your project if you move forward
2
TestSoil Profile Pit Test
We dig two soil profile pits and a licensed evaluator reads the real soil — texture, structure, depth to bedrock or groundwater, and any restrictive layers. That's the data a septic design actually stands on.
3
DesignEngineered Design & Report
The soil data goes to a licensed engineer, who sizes and stamps a system your county will approve — and you get a clear report of what your ground can support.
Perc & soil testing — questions
Do I need a perc test to build in Colorado?
If your property isn't on a sewer main, yes — you need the soil evaluated before an onsite wastewater (septic) system can be designed and permitted. In Colorado that evaluation is governed by CDPHE Regulation 43, and it's the first technical step on almost every mountain and rural build.
What's the difference between a perc test and a soil profile test?
A percolation test measures how fast water drains from a hole. A soil profile pit test digs deeper and reads the actual soil layers. On Colorado's variable mountain ground, the profile pit tells an engineer far more than a single drain rate — which is why it's the backbone of a real OWTS design. We dig two profile pits on every lot.
How much does soil and perc testing cost?
Everyone's first step with us is the $2,000 Site Feasibility Report — a licensed site visit, drone photos, and a code check — and it's credited toward your project if you move forward. We quote the profile pit testing itself after the feasibility, once we've seen the lot. No blind phone estimates.
How long does testing take?
The feasibility report is usually back within three business days. We schedule the profile pit testing after that; the field work is a single visit, and the engineered design follows from the results.
Can you test a steep or rocky mountain lot?
Yes — that's our normal. Decomposed granite, shallow bedrock, and slope are exactly the conditions profile pit testing is built to read, across Teller, El Paso, Park, and the rest of the Colorado high country.
What happens if my soil won't support a conventional system?
That's exactly what testing is for — finding out early, not after you've spent. If the soil is tight or the water table is high, we design around it with a pressure-dosed, advanced-treatment, or engineered system. The feasibility report usually tells us where a lot is headed before we ever dig.
Where we test
We run soil and perc testing across the Colorado high country and Front Range. Every county permits a little differently — pick yours:
Teller CountyEl Paso CountyPark CountyChaffee CountyFremont CountyCuster CountyHuerfano CountyDouglas CountyElbert CountyJefferson CountyBoulder CountyLarimer CountyClear Creek CountyGilpin CountySummit CountyEagle CountyGrand CountyGunnison CountyLake CountyPueblo CountyAdams CountyArapahoe CountyWeld County
From tested soil to finished system
SepticIQ · Instant plan-based estimate
Already have engineered septic or OWTS plans? Upload the PDF for an instant Colorado installation estimate, then have Tri-Lakes, a licensed Colorado OWTS installer, price and build the system.
Thinking about a lot? Test the soil before you commit.
Start with a Site Feasibility Report — $2,000, credited toward your project — and know what your ground can support before you buy or build.
Book a Feasibility Report