Expert Guide to Excavating a New Septic Field in Michigan

Written on 09/21/2024
Austin Wilbanks - Thumbs Up Excavation

Excavating a new septic field is a critical component of installing or replacing a septic system, which is essential for properties in rural areas or locations where municipal sewer systems aren't available. In Michigan, where environmental regulations are stringent to protect the Great Lakes and other water resources, ensuring a well-planned and executed septic field installation is vital. Below, we explore the essential steps, considerations, and regulations involved in excavating a new septic field in Michigan.

1. Site Evaluation and Soil Testing
Before excavation begins, the most important step is conducting a comprehensive site evaluation. A licensed septic professional will first assess the property to determine whether it is suitable for a septic system. Michigan law mandates soil testing, which includes conducting a percolation (perc) test to assess the soil’s ability to absorb and filter wastewater. Different soil types—such as clay, sand, or loam—will influence how effectively a septic system will function. Sandy soils, for instance, offer excellent drainage, while clay-heavy soils often hold water, necessitating special designs. A site’s slope and proximity to water sources like lakes, rivers, or groundwater are also evaluated. Michigan has strict regulations on minimum distances between septic fields and water bodies to prevent contamination.

2. Permitting and Regulatory Compliance
Michigan requires specific permits before any excavation can begin. Septic systems in the state are regulated by local county health departments, which implement the Michigan Department of Environment, Great Lakes, and Energy (EGLE) standards. Homeowners or contractors need to apply for a permit, which usually includes submitting the results of the soil tests, site evaluations, and a detailed septic system design. Regulations in Michigan aim to protect public health and the environment, ensuring that wastewater is properly treated before returning to the ground. A failure to comply with these regulations could result in legal penalties and expensive corrective actions.

3. Designing the Septic Field
The design of the septic system is tailored to the site conditions discovered during the evaluation phase. A septic system generally consists of a septic tank and a drain field (or leach field). The drain field is the area where effluent from the tank is released into the soil, and its design must ensure that wastewater is absorbed properly without risk of groundwater contamination.

In Michigan, some common designs include:
- Conventional Gravity Systems: These are used where the soil naturally allows for adequate drainage.
- Pressure Distribution Systems: In cases where soil conditions are less ideal, pressurized systems may be required to evenly distribute wastewater throughout the septic field.
- Mound Systems: These are often used in areas with shallow soils or high water tables, where the drain field is raised above the natural soil level.

Choosing the right design is key to the long-term success of the septic field, ensuring that the system works efficiently and complies with Michigan’s environmental standards.

4. Excavating the Drain Field
Once permits are secured and the design is approved, the excavation process can begin. This involves using heavy machinery to dig trenches or a large bed where the drain field pipes will be installed. The depth and width of the trenches depend on the type of system being installed, the site’s soil conditions, and the system's expected load based on household size or usage. Careful excavation is required to avoid damaging the surrounding environment, particularly in Michigan’s sensitive ecosystems. Erosion control measures may be needed to prevent soil runoff into nearby waterways during the excavation process.

5. Installing the Drainage System
After the trenches are dug, perforated pipes are laid in the excavated areas. These pipes are typically laid on a bed of gravel to enhance drainage and then covered with additional layers of gravel and soil. The pipes allow effluent from the septic tank to percolate into the surrounding soil, where it undergoes natural filtration before returning to the groundwater. During installation, care must be taken to ensure that the slope of the pipes is correct for proper drainage. Inadequate installation can result in blockages or poor absorption, leading to system failure.

6. Final Inspection and System Maintenance
Once the system is installed, Michigan law requires a final inspection by a licensed inspector. This inspection ensures that the system is built according to code and functions properly. Only after passing this inspection can the septic system be put into use. Maintenance is key to the long-term functionality of the septic field. Routine pumping of the septic tank (usually every 3-5 years) and regular checks for signs of system failure, such as slow drains or foul odors, are essential. If issues are identified early, costly repairs or full system replacements can often be avoided.

7. Environmental Considerations
Michigan’s unique landscape of lakes, rivers, and forests necessitates particular attention to environmental protection during septic system installation. For example, high water tables and proximity to bodies of water may require alternative designs like mound systems to prevent contamination. Additionally, homeowners should avoid overloading their septic systems with excessive water use or chemicals, as these can harm the bacterial balance in the septic tank and reduce the system’s effectiveness. Planting trees or shrubs with deep roots near the septic field should also be avoided, as roots can infiltrate and damage pipes.

Excavating a new septic field in Michigan is a detailed process that requires careful planning, adherence to environmental regulations, and expert execution. From conducting soil tests to ensuring the system complies with local and state regulations, each step is critical for the long-term success of the septic system. Working with licensed professionals familiar with Michigan’s specific requirements ensures that the project will meet both legal standards and the property’s needs while protecting the state’s valuable natural resources.