Sprinkler Water Usage Calculator
See what your watering schedule really uses. Add up flow across every head on a zone and find litres per session, per week, and per month, before the water bill explains it to you.
Your results
Worked example
A front lawn zone has 6 rotor heads at 10 L per min each, running 30 minutes, three times a week:
- Per session: 6 heads × 10 L per min × 30 min = 1,800 L
- Per week: 1,800 × 3 sessions = 5,400 L
- Per month: 1,800 × 3 × 52 weeks ÷ 12 months = 23,400 L, or 23.4 m³
Canadian municipalities bill water by the cubic metre, so the 23.4 m³ line is the one to compare against your utility rate and any seasonal sewer surcharge.
How this calculator works
Every head on the zone runs at once, so flows add. The monthly figure spreads the weekly schedule across an average month of 4.33 weeks. Flow rates are the weak point of any estimate: a head's real output depends on water pressure at the nozzle, and published charts assume rated pressure. The bucket test, timing how long one head takes to fill a known container, beats any chart.
Common questions
How much water does a lawn actually need?
About 25 mm per week is the standard guidance for established lawns in most of Canada, including rainfall. Measure what your sprinklers deliver with a few straight-sided cans set out during a session rather than trusting run time alone.
When is the best time of day to water?
Early morning. Less water is lost to wind and evaporation than at midday, and the lawn dries during the day, which discourages fungal disease compared with evening watering.
Estimates only. Results are provided for planning purposes and depend on the flow rates entered. Actual usage varies with water pressure, nozzle condition, and leaks. Check your municipal watering bylaws for permitted days and hours. Mississippi Maple accepts no liability for decisions made using this calculator.