FROM THE NGS FIELD NOTEBOOK
Why do you need a soils report?
A soils report helps your design team understand how the ground may affect the structure and site improvements you are planning. It brings together the geotechnical investigation, engineering evaluation and recommendations for the proposed development.
For a home, ADU or addition, the questions may include how to support the foundations, prepare the building area and address soil conditions that can affect movement or construction. For a larger development, the investigation may also need to consider deeper foundations, substantial grading, pavement, retaining structures or stormwater facilities.
Start with the proposed development
A useful investigation begins with a clear description of the project. Share the site plan and every planned improvement: the residence, ADU, pool, additions, walls and other relevant work. An investigation should be scoped around the complete development rather than an isolated part of it.
The building locations and loads, grading concept, existing improvements, slopes and available access all help define the field program. Previous soils reports and agency comments can provide additional context. If the plans are preliminary, identify the items that may change.
What happens during a geotechnical investigation?
NGS reviews available project and site information, plans appropriate exploration and obtains samples of the materials encountered. An engineer or geologist records the subsurface observations. Selected samples are tested to help evaluate engineering behavior relevant to the assignment.
The exploration method is chosen for the site and proposed work. Some smaller projects can be investigated with hand-auger equipment. Other developments or ground conditions require a drill rig, deeper exploration or a specialized investigation. There is no single field program that suits every property.
What does the report include?
The report describes the project and investigation, summarizes the conditions encountered and provides recommendations supported by the field and laboratory work. Depending on the scope, it may address site preparation and earthwork, foundations, slabs, settlement, expansive soils, groundwater, seismic considerations and other relevant geotechnical issues.
Logs, test results and other supporting information help the design team understand the basis of the recommendations. The report also identifies its limitations. A preliminary or shallow investigation does not automatically include every specialized study a site might need.
Does my project require a soils report?
The reviewing authority, development and site conditions affect what is needed. Send NGS the property location, available plans and any plan-check comments so we can help develop an appropriate scope. A previous report may be useful, but its applicability to a different building, layout or grading plan needs review.
Our residential and ADU soils-report service explains the process for smaller developments. For other work, see our geotechnical engineering services and documented project experience.
How do percolation testing and construction testing fit in?
A building investigation and water-related testing answer different questions. Septic percolation testing supports onsite wastewater planning. Stormwater infiltration testing provides field data for proposed drainage facilities. These services can be coordinated with a geotechnical investigation when the project requires them.
Observation and compaction testing during construction are a later phase. The soils report establishes recommendations; construction services document the agreed observations and testing as the work proceeds. Discuss those needs when planning the project.
What should I send to get started?
- The site address or assessor’s parcel number.
- A description of all proposed improvements and the current project stage.
- Available site, architectural, grading or structural plans.
- Previous reports and agency comments, if available.
- Information about access restrictions and your desired schedule.
Email is strongly recommended because Maihan is often in the field. Send the available information to maihan@noorzaygeo.com, or start a project inquiry. NGS will review the details before proposing the scope.
The original NGS explainer video
This video was shared with the original March 2018 article. The written guide above was expanded on October 25, 2026.