Water Usage Cost Calculator
Build your household water use from the big three fixtures, showers, toilets, and laundry, and see it in litres and dollars per month and per year.
Your results
Worked example
A household with 2 showers a day, 8 flushes a day, and 5 laundry loads a week, at $4.50 per m³:
- Showers: 2 × 65 L = 130 L a day. Toilets: 8 × 6 L = 48 L a day. Laundry: 5 × 90 L = 450 L a week, which is 64.3 L a day
- Total: 130 + 48 + 64.3 = 242 L a day
- Per month (30.44 days on average): 242 × 30.44 = 7,375 L, or 7.38 m³
- Cost: 7.375 m³ × $4.50 = $33.19 a month, and about $397.95 a year
How this calculator works
A month uses the average of 30.44 days (365.25 ÷ 12, allowing for leap years). The litres-per-use defaults are stated beside each field so you can swap in your own fixture figures; a low-flow shower head or a high-efficiency washer changes the picture a lot.
Common questions
Why is my real bill higher than this?
This calculator covers showers, toilets, and laundry only. Baths, dishwashing, cooking, outdoor watering, and leaks add more, and most utilities also charge a fixed monthly service fee on top of the per-cubic-metre rate.
How much does a running toilet waste?
A toilet with a worn flapper can leak 200 L or more a day without making a sound, nearly doubling the example household's use. The dye test is simple: food colouring in the tank, then check the bowl in 20 minutes without flushing.
Estimates only. Results are provided for planning purposes and are based on the figures and assumptions shown on this page. Actual use and rates vary by household and municipality. Mississippi Maple accepts no liability for decisions made using this calculator.