The air is dry in California so it has a huge capacity to absorb moisture from transpiration or evaporation. The prevailing winds will carry the water hundreds

The air is dry in California so it has a huge capacity to absorb moisture from transpiration or evaporation. The prevailing winds will carry the water hundreds of miles or more before it precipitates. They water crops year round, but there is almost no rain in the dry season, so that water is definitely going somewhere else. The other thing is photosynthesis. The oxygen is released into the air, and the retained hydrogen only accounts for 11% of the mass (although if you assume the O was replaced with ~1 C, then it's 77%). This often becomes part of the crop that's shipped off, but even if it sticks around to combust or decompose, the vapor can still blow away.