How often should fuel tanks be checked for water accumulation (sumping)?

• A. Daily
• B. Weekly
• C. Monthly
• D. Yearly

Answer: (A)

Water in fuel is a serious risk because it can cause engine roughness, fuel starvation, or damage if it reaches the engine. Water, being heavier than fuel, settles to the bottom of the tanks and collects in the sumps. Because conditions change daily—temperature swings, condensation, and fueling practices—water can accumulate between longer inspection intervals. Draining the fuel sumps daily, ideally before every flight, ensures any accumulated water is removed before you start the engine. The process is straightforward: open the bottom drain at each tank, observe what comes out, and drain until only clear fuel flows. If water is found, address the source and ensure the system is clean before flight. That daily practice minimizes risk far better than weekly, monthly, or yearly checks, which can miss new water accumulation.