Backwash Water Calculator
Calculate filter backwash volume, frequency, and supply requirements for water treatment plant filter maintenance.
Inputs
sq ft
gpm/ft²
minutes
hours
gpm/ft²
Results
Volume per Backwash (per filter)
60K gallons
Daily Backwash Volume
124.8K gallons
Backwash % of Production1.4%
Peak Backwash Flow6,000 gpm
Supply Tank Size74.9K gallons
Backwash Pump Size61 HP
Rise Rate24.1 in/min
Est. Bed Expansion48%
Backwashes per Day0.5
Annual Backwash Volume45.6 MG
Annual Backwash Cost$137,210
Peak BW Flow MGD8.64
How to Use This Calculator
- Enter Filter Area (sq ft per filter) and Number of Filters in the plant.
- Set Backwash Rate (gpm/ft²) based on your filter media type — typically 12-20 gpm/ft² for sand filters.
- Input Backwash Duration (minutes) and Filter Run Length (hours) from your operational records.
- Add Surface Wash Rate (gpm/ft²) if your filters use a surface wash system in addition to backwash.
- Review Volume per Backwash and Daily Backwash Volume (K gallons) to size your backwash supply tank.
- Check Backwash % of Production to ensure recovery losses stay within permit and efficiency limits.
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