A grey water pit is a relatively deep disposal trench or bed, or a cylindrical excavation, usually backfilled with aggregate, or sometimes provided with specially fabricated liners. If the grey water is first filtered to remove food solids and grease, the sump can be an acceptable means of disposing of grey water. A grey water disposal field is a system of disposal pits.
The biggest challenge to the grey water disposal pit or field in the high alpine is the limited soil mantle.