Most experts recommend a shower head flow rate between 1.5 - 2.5 GPM (gallons per minute). Flow rates lower than 1.5 GPM may have unsatisfying pressure, while higher flow above 2.5 GPM wastes water. Within this ideal range, 2.0 - 2.5 GPM provides the best balance of water savings and strong pressure for most users. Shower heads with air injection or pressure-boosting technology can also help ensure good water coverage at lower flow rates.