What happens if water enters a trach?

Depends on amount: If small amount of h2o goes down the wrong tube (trachea instead of esophagus), the healthy person can cough it up. If very weak from a diseae or being frail and elderly, then even small amounts can be be difficult to clear, and aspiration of the fluid may result. If a large amount of water fill the lung and prevent air exchange at the alveoli, could lead to death by drowning.