Food & drink · Water
Bottled water vs tap cost.
Enter the price and size of a bottle and your tap rate per cubic metre to compare the cost per litre and the yearly difference, with an optional filter cost.
Inputs
Your comparison
Enter the bottle price and your tap rate.
How to compare bottled water and tap water cost
Bottled cost per litre = bottle price ÷ bottle size in litres. Tap cost per litre = your rate per cubic metre ÷ 1,000, because a cubic metre is 1,000 L. Multiply either by litres per day and 365 for the year. If you use a filter or pitcher, add its monthly cost to the tap side.
Worked example (example numbers, replace with your own). A 500 mL bottle at $1.50 is $3.00 per litre. Tap at $4.00 per cubic metre is $0.0040 per litre. Drinking 2 L a day, bottled costs $2190 a year and tap $2.92, a difference of $2187. Add a $10 a month filter and tap costs $123 a year, still $2067 less.
Cost only. The tool says nothing about water quality or taste. If your area has a boil-water advisory, or you have a health reason to avoid tap water, follow your local health authority.
Frequently asked questions
How much cheaper is tap water than bottled water?
It depends on your rate and bottle. With the example numbers, bottled costs $3.00 per litre and tap $0.0040.
How do I find my tap water rate?
Look at your water bill or your municipality’s website for the rate per cubic metre, and add the wastewater charge if it is billed separately.
How many litres are in a cubic metre?
A cubic metre is 1,000 litres, so divide the rate per cubic metre by 1,000 for the cost per litre.
Should I include the cost of a filter?
If you filter tap water, yes. Enter the monthly cost of cartridges or filters and the tool adds it to the tap total.
Sources
Checked
This tool is arithmetic on the prices you enter. The only fixed figure is 1 cubic metre = 1,000 litres.
Runs entirely in your browser. Nothing you type is sent or stored.
Scope
Cost comparison only, not advice about water safety or quality. Follow your local health authority on boil-water advisories.