In a paramecium, water typically leaves the contractile vacuole, which is an organelle responsible for expelling excess water from the cell. When water is leaving the vacuole, it indicates that the water concentration is higher inside the paramecium than outside. This situation occurs because the paramecium lives in a freshwater environment where water tends to move into the cell due to osmosis.
The process of water moving out of the vacuole is known as exocytosis, specifically in this context, it is part of the function of the contractile vacuole as it expels excess water to maintain osmotic balance.