Borehole latrines have an augered hole instead of a dug pit and may be sunk to a depth of 10 m or more, although a depth of 4-6 m is usual. Augered holes, 300-500 mm in diameter, may be dug quickly by hand or machine in areas where the soil is firm, stable and free from rocks or large stones. While a small diameter is easier to bore, the life of the pit is very short. For example a 300-mm hole 5 m deep will serve a family of five people for about two years.
The small diameter of the hole increases the likelihood of blockage, and the depth of the augered hole increases the danger of groundwater contamination. Even if the hole does not become blocked, the sides of the hole become soiled near the top, making fly infestation probable. However, borehole latrines are convenient for emergency or short-term use, because they can be prepared rapidly in great numbers, and light portable slabs may be used.
The holes should be lined for at least the top half-metre or so with an impervious material such as concrete or baked clay. Because of the small diameter and short life, the full depth is not usually lined.