Irrigation Water Rechner — Formel

How to Calculate Irrigation Water Needs

Lawns and gardens need about 1 inch of water per week, including rainfall.

Formula

Weekly Gallons = Area * (Need - Rainfall) * 0.623 / Efficiency

Irrigation Efficiency

  • Drip irrigation: 85-95%
  • Sprinkler: 60-75%
  • Flood/furrow: 40-60%

    • Overwatering is the most common irrigation mistake, wasting both water and money.

    Lösungsbeispiel

    3,000 sq ft lawn needing 1 inch/week with 0.5 inches rain at 75% sprinkler efficiency.

    1. Water deficit: 1.0 - 0.5 = 0.5 inches
    2. Weekly gallons: 3,000 * 0.5 * 0.623 / 0.75 = 1,246 gallons
    3. Monthly: 1,246 * 4.33 = 5,395 gallons
    4. Season (26 weeks): 1,246 * 26 = 32,396 gallons