There’s no one-size-fits-all answer to this question of how much water you should drink daily to effectively combat dehydration as two litres of water per day (or 8 cups) has been called ‘misleading’. Biomedical engineer Kong Chen, a director for the metabolic research program at the National Institutes of Health’s Clinical Center, said that “individual variability could be huge” between people and their required intake.
Fortunately, there are free services like Hydration Calculators that you can access online to get an answer that is suitable for you based on your personal circumstances.