The difference between building near Lake Austin and developing on the clay-rich uplands east of I-35 isn't just the view. It's the water. In Westlake Hills, fractured limestone of the Edwards Formation can drain a pond in hours if you don't quantify the mass permeability correctly. Over in the Blackland Prairie zones, tight expansive clays hold water and create hydrostatic pressure against basement walls. Both scenarios demand the same thing before you move a single yard of dirt: reliable field permeability data. Our team runs Lefranc tests in soil boreholes and Lugeon tests in rock to give you the in-situ hydraulic conductivity numbers that desk studies can't predict. When we combine these with test pits for visual soil profiling, you get a complete picture of how water moves through your site.
A single packer test in fractured limestone can save a developer from a multimillion-dollar water inflow problem during excavation.
Methodology and scope
Local considerations
The most common mistake we see in Austin is contractors assuming a soil boring log is enough to design an infiltration system. It isn't. A visual classification of 'silty clay' tells you nothing about field hydraulic conductivity, and that number can vary by two orders of magnitude depending on macropores, root holes, or fissures in the weathered rock. We've inspected detention basins that failed because the designer used a textbook permeability value from the lab while the actual in-situ rate was 10 times lower. The basin overflowed into the adjacent property, and the legal headache lasted two years. A two-hour Lefranc test during the geotechnical investigation would have caught the discrepancy. If your project falls within the Edwards Aquifer contributing zone, additional in-situ permeability documentation is not optional; it's a regulatory requirement for TCEQ compliance.
Regulatory framework
Field permeability testing in Austin (Lefranc & Lugeon) conforms to ASTM D6391-11, ASTM D2487-17e1, ASTM D1586-18, the City of Austin Environmental Criteria Manual, and the TCEQ Edwards Aquifer Protection Program.
Other technical services
Lefranc Permeability in Soil
Constant and falling head tests in soil boreholes for infiltration rate design, stormwater compliance, and retention pond sizing. We test at multiple depths to capture vertical variability in the soil profile.
Lugeon Testing in Rock Mass
Single and double packer tests in NQ/HQ core holes to evaluate rock mass permeability. Essential for grouting design, deep excavation planning, and slope stability analysis in the Edwards Limestone.
Permeability for Environmental Compliance
Testing programs designed to meet TCEQ requirements for the Edwards Aquifer contributing and recharge zones. We coordinate with your environmental consultant to deliver defensible data for permit applications.
Typical parameters
Frequently asked questions
What does a Lefranc or Lugeon test cost in Austin?
How long does a field permeability test take on site?
A single Lefranc test in soil usually takes 45 to 90 minutes once the drill rig reaches the target depth. A multi-stage Lugeon test in rock can take two to four hours depending on the number of pressure stages and the packer setup time. We can typically complete a standard program of four to six tests in one field day.
Do I need a Lugeon test or is a Lefranc test enough?
It depends on the geology at your test depth. If you are testing in soil, residual clay, or completely weathered rock, a Lefranc test is appropriate. If you are testing in competent limestone where fractures control the flow, you need a Lugeon test with a packer system. Many Austin sites require both, starting with Lefranc in the upper soil zone and switching to Lugeon once we hit bedrock.
Can you test below the water table?
Yes, we routinely perform Lefranc and Lugeon tests below the water table. For these tests we use a falling head method in soil or constant pressure injection in rock. The data is corrected for hydrostatic pressure and we report the in-situ saturated hydraulic conductivity. This is common for deep excavations and basement waterproofing design in Austin.