Your technically right. That Water (H2O) itself is lost. However living things also create water (vapor) to move, grow, think, or do anything really. Also burning things creates water vapor. The vapor will become water eventually.

Furthermore plants also use water to grow. this 5% you are talking about probably refers to the water that plant used to create new cells. This water can eventually become water by burning it.

Also, even if some water is lost forever and never becomes water again. The percentage is small. So small i fact that it does not really matter