Water & environment
Garden irrigation water Calculator
Calculate supplemental water, hose run time and metered cost. This free garden irrigation water calculator shows the calculation and its assumptions so you can compare your own figures.
Your results
Calculate supplemental water, hose run time and metered cost.
Calculated outcomes
- Net Depth MM
- 15 mm
- Plant Water Litres
- 1,500 L
- Water Cost
- €0.00
Assumptions and estimates
- Method: Net depth = max(0, target − effective rainfall). Litres = area × net depth ÷ efficiency; time = litres ÷ flow.
- Target depth depends on plants, soil and weather. Price is optional and not a statement that ordinary Irish domestic water is charged; restrictions and runoff are excluded.
Useful next steps
- Use Compare options to test an alternative side by side.
- Copy, print or download a record of this calculation when you need one.
Reports open your email app addressed to s@s1.ie with the public page address only. Your inputs are never added.
How the garden irrigation water calculation works
Net depth = max(0, target − effective rainfall). Litres = area × net depth ÷ efficiency; time = litres ÷ flow.
Target depth depends on plants, soil and weather. Price is optional and not a statement that ordinary Irish domestic water is charged; restrictions and runoff are excluded.
Using this calculator
- Enter your own figures in the labelled inputs. Keep the currencies, units and time periods consistent.
- Choose any applicable rate profile, pattern or assumption shown for this tool. Open additional inputs when relevant.
- Review applied litres and watering minutes, then read the stated assumptions and eligibility conditions before using the result.
Worked example
This is a static example using illustrative inputs, not facts about you or today’s date. The displayed eligibility selections and assumptions apply only to this example.
See example inputs
- Garden area (m²)
- 100
- Target watering depth (mm)
- 20
- Effective recent rainfall (mm)
- 5
- Application efficiency (%)
- 80
- Measured flow (litres/minute)
- 12
- Applicable metered water price (€/m³)
- 0
- Applied Litres
- 1,875 L
- Watering Minutes
- 156.25 min