Annual Water Usage
==================

For physical trough, power tower, and linear Fresnel systems, SAM reports the total annual water consumption in cubic meters for cooling and mirror washing.

**Annual Water Usage**
*Annual Water Usage (m³) = Cooling Water Usage (m³) + Mirror Washing Water Usage (m³)*

  The mirror washing water usage is based on the mirror washing parameters you specify on the Solar Field or Heliostat Field page:

*Mirror Washing Usage = Water Usage per Wash (L/m², aperture) × Total Aperture or Reflective Area (m²) × Washes per Year (1/year)*

SAM reports the annual mirror washing usage as a Single Values variable in :doc:`Tables <../results/data>` and :doc:`Graphs <../results/graphs>`. It also reports the cooling water flow rate in Tables as an hourly variable ("water makeup flow rate" or "water consumption mass flow rate").