Skip to content
SARZAMEEN BuyRentAgentsBlog

Rainwater Harvesting Calculator

Enter the roof area and your yearly rainfall to estimate how much water you can store.

Enter your details

mm
Look up your city. Quetta is roughly 250 mm.
litres

Pakistan Lands Tools | Rainwater Harvesting Calculator

Estimate generated 17 Oct 2026 | https://www.property.candletrack.pro/public/buildcraft/tool/rainwater-harvesting-calculator

Results

Enter your values and press Calculate. Results will appear here and update as you change inputs.

    Rainfall varies from year to year. Treat harvested water before drinking.

    How this calculator works

    • Water = roof area (m²) × rainfall (mm) × runoff factor × 0.9 (first-flush loss).
    • Runoff factor: concrete 0.8, tiles 0.75, metal 0.9.

    Frequently asked questions

    Not without filtering and disinfecting. It is mainly used for gardens, cleaning and flushing.

    Related tools

    Construction Timeline PlannerEstimate how many weeks each stage of a house build will take. Home Loan EMI CalculatorMonthly instalment, total interest and yearly balance for a home or construction loan. Water Tank Size CalculatorDaily water demand and the tank size for a house, with a suggested underground and overhead split. Material Truckload CalculatorHow many truck trips are needed to deliver sand, crush, bricks, blocks or steel.