Site & Soil Evaluations in Puyallup, WA
Your septic system is only as good as the soil beneath it. A site and soil evaluation, also called a perk test, determines whether your property can support a septic system and what type of system will work best.
We conduct professional soil percolation testing to measure how quickly your soil absorbs water. This critical first step analyzes your soil type, drainage rates, groundwater depth, and site slope to assess feasibility. Without this evaluation, you could face costly problems later. Our certified team follows Washington State regulations precisely, testing multiple locations on your property to give you accurate, reliable results that satisfy county requirements.
The evaluation process typically begins with a deep hole test dug by machine to well below the bottom of the proposed drain field. Testers look for the seasonal high water table, the presence of rock ledge, or impermeable soil that could block absorption. Soil samples and visual observations of the soil layers help identify what’s called the “limiting zone,” where the soil is unsuitable for treating wastewater. The seasonal high water table is identified by looking for mottling, which refers to splotches or streaks of color in the soil that indicate the occasional presence of water.
What We Evaluate
The perk test reveals what your soil can actually handle. During our evaluation, we assess several key factors:
- Soil composition and classification (sand, silt, clay, gravel combinations)
- Percolation rate (how fast water drains through soil layers)
- Groundwater table depth and seasonal variations
- Site slope and drainage patterns
- Presence of bedrock, rock layers, or other barriers
- Setback distance requirements from wells, property lines, and water bodies
- Mottling indicators and limiting zone depth
Each of these factors affects what type of septic system your property can support. The percolation rate specifically dictates the size of your drain field and whether a conventional gravity system will work or if a pressurized or alternative system is needed.
Why a Proper Evaluation Matters
Soil type varies dramatically across King, Pierce, and Thurston Counties, from sandy and gravelly soils that drain quickly to clay soils that require special systems or modifications. We provide detailed documentation of our findings, including soil classification, percolation rates, and any site restrictions like high groundwater or unsuitable layers. This data becomes the foundation for your septic system design, giving your designer everything needed to engineer the right solution.
Many property owners save money and time by getting a proper evaluation upfront rather than discovering problems during the permitting process. If your soil doesn’t pass a standard perk test, that doesn’t necessarily mean you can’t build. It may mean you need an alternative system type. Our evaluation gives you the full picture so you can plan accordingly.
All modern septic codes in Washington require that perk tests be conducted on undisturbed soil. The drain field must also be placed on undisturbed soil. Both the primary drain field area and the required reserve area must pass testing. We handle all of this during your evaluation and document everything the county needs to see. Whether you’re planning a new construction project, adding a remodel or ADU, or developing a commercial property, the soil evaluation is always the first step.
Schedule Your Site and Soil Evaluation Today
A site and soil evaluation is where every septic project begins. All Septic Designs LLC provides professional perk testing across King, Pierce, and Thurston Counties for residential, mobile home park, and commercial properties. Reach out to our team and we’ll give you the facts you need to move forward with confidence.
