Geologist’s Role in Percolation Testing

Septic systems are being actively used in Southern California. This is particularly evident in hilly and rural regions, as well as in properties without sewer connections. Such systems rely fully on soil environments. Moreover, Agencies like Los Angeles County, LADBS  , Caltrans, and LA Metro rely on accurate soil data.

The first step in safe septic design is percolation testing. It determines the speed at which water passes through soil. This information specifies the permitted dimensions, depth, and system type. Should the percolation testing in Los Angeles County not be a casual exercise?

The County needs competent specialists. In most cases, input from a licensed geologist is required. This is attributed to complicated geology, fluctuating soils, and groundwater issues. The article justifies the importance of geologists. It explains what they do. It outlines the process for reviewing and approving percolation testing in LA County.

Why LA County Requires a Geologist for Percolation Testing

There are strict regulations for on-site wastewater systems in California. These systems are referred to as OWTS. The goal is simple. Conserve drinking water and human health.

The LA County implements such rules under different departments. These are the Department of Public Health, Environmental Health Division.

They establish local standards in their OWTS Manual. These standards tend to be more stringent than state-level minimums.

The soils in many parts of LA County are challenging. Expansive clays are common. Bedrock has been fractured extensively. The groundwater may be either shallow or seasonal. These circumstances render failures as a probability.

LA County typically requires a California-licensed Certified Engineering Geologist for the reasons mentioned. It requires a specialist soil technician; a generalist is not enough.

A geologist is tasked with determining the conditions below ground. They are also in a position to sign and seal reports where necessary.

What Is the Geologist’s Role in a Percolation Test?

The geologist’s work begins before any excavations. They initially prospect the history of sites. They read maps, satellite photographs, and reports on the area. This helps detect risks promptly. This is followed by site reconnaissance.

The geologist explores the ground. They note inclinations, drainage lines, and plants. These characteristics are usually a sign of the underground.

Later on, the geologist determines the soil profiles. This involves texture, structure, and consistency. They seek clay layer, filler soils, or cemented areas.

The sites of percolation tests are chosen. The geologist can make tests reflect the actual disposal location. Randomly made holes are not valid.

The geologist monitors processes during the testing. It is important to pre-soak the agricultural product. In the absence of this, there are misleading results.

The geologist records the data after testing. They comprehend the absorption rates. They also verify that they are vertically separated from groundwater or impervious layers. This is a requirement in LA County.

The percolation testing and analysis for septic tank construction helps prevent project delays and closures. Properly framed inspections safeguard schedules, jobs and project budgets. The Los Angeles Department of Building and Safety says visual checks help catch early problems.

LA County Standards for Percolation Testing

LA County determines how tests should be conducted. The number of test holes varies with system size and site complexity.

Larger systems need more holes. The depth of the proposed system should match the depth of the test. Shallow testing cannot be done when deeper disposal is required.

Spacing between holes is also controlled. This ensures there is no clustering or bias in the results.

Soil logs need to be in detail. Each layer must be described. Characteristics such as texture, moisture, structure, and color should be mentioned.

The procedures used for testing are based on the LA County OWTS Manual. There is a set of pre-soak, drop, and measurement procedures.

System eligibility depends on test results. The slow soils might need seepage pits. Increased soil can permit leach fields and can turn away certain sites altogether.

Read more to find out why a percolation testing can help properly develop a property and construction stability, along with avoiding health concerns.

Geotechnical engineers conducting on-site soil sampling in Los Angeles County as part of a Geotechnical Report Southern California projects require for grading and foundation design.

Percolation testing and soil analysis performed by a licensed geologist for LA County onsite wastewater system (OWTS) permitting.

Geotechnical Report Requirements

The end geotechnical report is fundamental. LA County has been depending on it to approve decisions.

The plan should contain a proper site plan. All test locations should be displayed. Boundaries of property are mandatory.

Each test hole has soil profiles attached to it. Such profiles should align with field logs.

There is a compulsory condition of groundwater observations. These encompass perched water, seepage, or records.

The geologist will be required to give a narrative assessment. This is a simple explanation of site conditions. It describes restrictions as well.

The LA County Environmental Health reviews the report. Other agencies in the hillside areas can also review it.

Designing Seepage Pits or Septic Fields Based on Test Data

The Seepage Pits or Septic Fields are to be designed using Test Data. The development of septic systems is not a geologist’s responsibility. Engineers do.

Yet it is built on geologists’ work. The geologist can advise on the rate of soil absorption based on test data. These rates regulate the size of systems.

They are also detecting minimum setbacks. This covers the area around buildings, gradients, and property boundary lines.

Poor soil classification results in failure. A common mistake is taking clay for sand. The assistance of a geologist avoids this.

Design is a team effort. Civil engineers and installers work in geology. Each role matters

LA County Permit Review Process

Reviewing the permit begins with submission. There is a need to have percolation information and the geotechnical report.

Review timelines vary. Simple sites move faster. Hillside sites take longer. Missing signatures, incoherent logs, or inconsistent data are the common types of corrections.

Sometimes testing fails. In such cases, redesign or re-testing may be necessary. There are also instances when the location is considered to be unsuitable.

Common Pitfalls and Red Flags in Percolation Testing

The absence of the geologist’s signature is also a significant difficulty. Reports that are not signed are rejected.

Another issue is the bad description of geology. Bread and butter language is suspicious.

Wet-season testing may yield distorted results. LA County frequently questions such information.

Shallow groundwater is occasionally neglected. This leads to unsafe designs.

It is not permitted to use old or borrowed data. Site-specific testing is required at every site.

Why Hiring a Qualified Geologist Matters

Hiring a good geologist is one way to reduce risk. The failure of septic systems often results from misconceptions about the conditions underground. A geologist can improve percolation testing as follows:

  • A geologist can identify such dangers in advance. A developing geologist has a professional responsibility. The state licensing laws defend their practice. Their interpretations and conclusions are their responsibility. This is a vital responsibility for safeguarding people’s health. Geologists assist in preventing system failure.
  • An incorrect soil classification is more frequently the cause of septic malfunction. Slow-draining clay soils have often been confused with one another.
  • A geologist could tell the difference between sand, silt, and clay layers. They also help reduce code violations. The OWTS requirements in LA County are tough. A geologist ensures that testing is conducted in accordance with the County’s existing standards.
  • Local knowledge matters. The geology of LA County is complicated and diverse. Soil conditions can vary over a short distance. There could be fill, native soil, and bedrock in the same disposal area on a single property.
  • Hillside sands behave differently from coastal sands. Widespread clay contracts and expands with changes in moisture. This movement can destroy seepage pits and leach lines. Sandy soils have higher drainage rates but may have poor filtration. A geologist comprehends these behaviors.
  • The seasoned geologists are also conversant with LA County plan review expectations. They are familiar with what the Environmental Health reviewers seek.
  • They understand how to make presentable soil logs and draw justifiable conclusions. This minimizes the number of comments and revisions. This is, in most instances, a time- and money-saver.
  • Fewer approvals take shorter periods. Avoiding re-testing or costly redesigning is also due to proper testing. A qualified geologist safeguards the environment and the property owner in the long run.

Conclusion

Geologists are also critical in the percolation test. Their effort safeguards groundwater and human health. A

Approval of septic systems in LA County is based on proper soil assessment. This cannot be rushed.

The LA County OWTS Manual should be adhered to. When in need, one should always have a licensed geologist on hand.

Good data lead to good design. Safe systems result from proper testing.

F.A.Q.s

Is a geologist required for all percolation tests in LA County?

Not always. Simple sites may allow other professionals. Complex sites usually require a geologist.

What license must a geologist hold in California?

The State of California must license them. Engineering geologists hold additional certification.

How do I find a qualified geologist near Los Angeles?

Look for professionals experienced with LA County Environmental Health reviews.

Can an engineer sign off without a geologist?

Only in limited cases. Many sites still require geologic evaluation.

What happens if groundwater is found?

The system design must change. In some cases, the site may be denied.

Build with knowledge. Build with confidence. Build smart from the ground up.