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🌊 Filter Loading & Backwash Rate Calculator

Calculate filtration hydraulic loading rates (gpm/sq ft) and backwash bed expansion rise rates.
GPM
Hydraulic Loading Rate
4.00 gpm / sq ft
Equivalent Backwash Bed Rise Rate: 6.42 inches/minute
📝 Calculation Steps
Loading Rate (gpm/sq ft) = Flow (GPM)Surface Area (sq ft)

Standard Filtration Rates in Drinking Water

  • Conventional Rapid Sand: 2.0 to 3.0 gpm/sq ft
  • High-Rate Dual Media / Mixed Media: 3.0 to 6.0 gpm/sq ft
  • Typical Backwash Rate: 15.0 to 25.0 gpm/sq ft (approx. 24 to 40 inches/min rise)

📘 Theory & Exam Guide

Understand filtration loading rates, head loss triggers, and washwater formulas.

Read Filtration & Backwash Hydraulics Guide →

⚡ Filtration Rates

  • Rapid Sand Max3.0 gpm/ft²
  • Dual Media Max6.0 gpm/ft²
  • Rise Rate Ratio1.604 in/min per gpm/ft²

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