Not all septic systems are the same. The design used on your property depends on soil conditions, slope, and local health regulations. Understanding which type you have—or need—can help you maintain it properly and plan for long-term performance.
At Summit Septic Solutions, we install and maintain both conventional and alternative systems throughout Central Washington, each tailored to site-specific requirements.
1. The Role of Soil and Site Conditions
Before a septic system is installed, a licensed designer evaluates your property’s soil, elevation, and available space.
These factors determine whether wastewater can move naturally through the soil or if it requires assistance:
- Soil Permeability: Sandy soils drain quickly and may only need a standard gravity system.
- Shallow or Clay Soils: These often require pressurized or alternative systems to ensure proper treatment.
- Slope & Groundwater: Steep or high-water-table lots usually can’t rely on gravity flow alone.
2. Conventional Septic Systems (Gravity Flow)
Best suited for: Level lots with deep, well-draining soils.
A conventional gravity system uses simple physics—water flows downhill.
How it works:
- Wastewater enters the septic tank where solids settle.
- Effluent exits the tank and flows by gravity into a network of perforated pipes buried in gravel trenches.
- The soil beneath the trenches completes the final treatment.
Advantages:
- Lower installation and maintenance costs.
- Fewer mechanical parts (less to service).
- Proven reliability when soil and site conditions are ideal.
Limitations:
- Requires sufficient soil depth.
- Not suitable for steep or wet properties.
3. Alternative Septic Systems
When gravity flow isn’t possible, alternative systems step in. These use pumps, pressure distribution, or enhanced treatment units to ensure wastewater is properly treated before reaching the soil.
Common Alternative Systems Include:
- Pressure Distribution: Uses a pump to evenly distribute effluent across the drainfield, reducing overloading.
- Sand Filter Systems: Effluent passes through sand media for added filtration before entering the drainfield.
- Mound Systems: Built-up sand mounds allow treatment where soil depth is limited.
- Aerobic Treatment Units (ATUs): Use oxygen and active bacteria to break down waste faster than anaerobic systems.
Advantages:
- Work on challenging lots (shallow, rocky, or sloped).
- Provide enhanced wastewater treatment.
- Can extend usable property options for new builds.
Limitations:
- Higher upfront cost.
- Require regular inspections and maintenance contracts.
4. Identifying Which System You Have
If you’re unsure about your septic system type, check your as-built drawings or contact your county health department.
Homeowners can also look for clues:
- Pump Alarms or Control Panels: Indicate a pressurized or advanced treatment system.
- Mound or Raised Bed: Suggests a sand or mound system.
- Simple Tank and Gravity Lines: Usually a conventional design.
5. Maintenance Requirements
Each system type has unique care needs:
- Gravity systems: Pump every 3–5 years and inspect baffles.
- Pressurized systems: Inspect annually; maintain pumps and alarms.
- ATUs or sand filters: Require service provider maintenance twice a year.
Conclusion
Both conventional and alternative systems perform the same essential job—safely treating household wastewater—but the right design depends on your property’s conditions.
At Summit Septic Solutions, we evaluate your soil, slope, and household needs to recommend and install the best long-term system for your home.
👉 Learn more about our Septic Installation Services or schedule a site consultation today.