Sand Filter Technology
The Eljen GSF (Geotextile Sand Filter) is an alternative septic system that uses a contained sand bed wrapped in geotextile to treat effluent before it reaches the soil. Ideal for high water tables, tight lots, and poor percolation.
Understanding Eljen GSF (Geotextile Sand Filters)
An Eljen GSF module is a corrugated plastic chamber wrapped in a specialized geotextile fabric and surrounded by a sand or native soil bed. As septic tank effluent is dosed into the module, it seeps through the geotextile into the surrounding sand. This fabric layer is where the magic happens — a thick, biologically active mat (called a bio-matt) develops on the interior surface of the fabric. This bio-matt acts as a living filter, consuming pathogens and organic matter before the effluent ever contacts the native soil below. The result is a highly treated effluent that meets or exceeds the requirements of Arizona county health codes, even on challenging sites with clay soils, high groundwater, or tight lots where a standard drainfield would fail a perc test.
Why Choose a Passive Alternative System in Arizona?
Unlike aerobic systems that rely on blowers, pumps, and control panels, the Eljen GSF is a 100% passive system — it requires no electricity, no moving parts, and no mechanical components to achieve advanced treatment. For Arizona property owners in rural areas where power reliability may be a concern, or for anyone seeking to minimize long-term maintenance costs, this is a major advantage. Eljen modules also allow drainfield sizing to be reduced by up to 50% compared to conventional rock-and-pipe systems in equivalent soils, making them an excellent solution for smaller lots in Maricopa, Pinal, and Yavapai counties where available land area is limited.
Key Benefits
- Effective in high groundwater and clay
- Consistent treatment quality
- Reduces drainfield size requirements
- Accepted across Arizona counties
