Borehole casing is not glamorous, but getting it wrong costs more than getting the drilling wrong. Here is what casing does, which materials are used, and what compliance requires.
Casing serves three functions: it stops the borehole walls from collapsing into the drilling, it prevents surface water and shallow groundwater from contaminating the production zone, and it provides the mechanical structure that the pump hangs from. Skimping on casing depth or material is one of the most common causes of early borehole failure in South Africa.
In most domestic boreholes, uPVC casing is used from surface to the production zone. The casing is grouted in place at the surface to prevent shallow water from running down the outside. A wellhead completion cap keeps debris and insects out. For high-yield agricultural or commercial boreholes, mild steel casing is often specified. All casing work on Borehole Central projects meets the requirements of SANS 10299.
