Quick Answer
The water table is critical when selecting casing because it determines the depth at which the casing should extend below the ground surface to prevent contamination and ensure a safe, reliable water source.
Protection from Contamination
When the water table is present at a shallow depth, the risk of contamination from surface activities such as agricultural runoff, sewage, or industrial waste is significantly higher. To mitigate this risk, the casing should extend at least 12-15 feet below the bottom of the well to ensure that any potential contaminants are filtered out before reaching the water supply. This can be achieved by using a casing material that is resistant to corrosion and can withstand varying water pressure, such as HDPE (high-density polyethylene) or PVC (polyvinyl chloride).
Well Construction and Hydraulics
In areas where the water table is deep, the casing may not need to be as long, but it’s still essential to ensure that the well is constructed to withstand the local hydrostatic pressure. A well with a deeper casing may require a more extensive well screen to allow for proper water flow, which can be achieved using a screen length of 6-12 inches and a slot size of 1/8 to 1/4 inch. This will help to prevent clogging and ensure a steady water supply.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.