A chamber system replaces the gravel-and-pipe trench of a conventional field with open-bottom, arch-shaped plastic chambers set directly on the trench floor. Effluent enters the open chamber, has room to pool and be stored temporarily, and then infiltrates the native soil below, without needing hauled-in gravel to create that void space.
The chamber itself performs the void-space role gravel plays in a conventional trench, storing effluent while it soaks into the soil beneath. That means less material has to be trucked to the site, and installation is often faster, which is part of why chambers have become a common substitute for a gravel trench even where soil conditions would allow either.
Because the trench bottom is left as native soil rather than being disturbed and refilled with gravel, chamber systems can also preserve more of the soil’s natural infiltration structure at the infiltrative surface, which some designers view as a performance advantage on suitable soils.
Chambers are typically used within a conventional gravity or pressure-dosed layout; they are a trench design choice, not a different treatment method, so the same soil, water table, and setback requirements that apply to any drainfield still apply.
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Open-bottom plastic chambers replace gravel to create the storage void above the infiltration surface, cutting down on hauled-in material and often speeding installation, while the underlying soil requirements are the same as any drainfield.
No, it's a trench design choice within a conventional gravity or pressure-dosed layout, not a separate treatment technology.
Guide last reviewed 2026-08-31.