What does decrease in water potential mean? (Lower negative value?) What does decrease in water potential mean? (Lower negative value?) Solution Answer: Water potential is a physical property of water that determines the direction that water will flow. Pure water (distilled) has zero potential. Addition of solute decreases water potential whereas or application of pressure increases the water potential. Decrease in water potential means increase in solute concentration and/or decrease in pressure. Water moves from higher potential to lower potential..