When asking for a well drilling cost or estimate you will be given a standard price, one for drilling and one for the cost of steel casing. Currently on Vancouver Island, British Columbia.... the cost of drilling a well will roughly be $20.00 per foot for drilling and $20.00 per foot for casing. The casing will only need to be installed untilwater well driller hits bedrock, the 6" steel casing is used to support the over-burden material... dirt, sand, clay, gravel etc. Once the well drilling bit drills into solid bedrock the steel casing is no longer required as the borehole will be self-supporting.
The installation of steel casing can almost double the cost of drilling a well... sometimes there might only be 20' of casing required before the driller hits rock, once the well driller is into rock the casing will be properly grouted and sealed preventing possible surface or sub-surface water from entering and contaminating the new water well.