Why should an observation well be fitted with a watertight cap?

An observation well should be fitted with a watertight cap primarily to prevent groundwater contamination. By sealing the well with a cap that is designed to withstand environmental factors, it serves as a protective barrier against pollutants, debris, and other contaminants that could infiltrate the well. This is crucial in maintaining the integrity of the groundwater supply and ensuring that the water quality remains safe and unaltered by external influences.

While accurate water quality readings and compliance with aesthetic standards are important considerations in well management, the primary function of a watertight cap is to safeguard the groundwater source itself. Ensuring that contaminants do not enter the observation well is a fundamental aspect of well monitoring and contributes to the overall health of the aquifer and the surrounding ecosystem.