The cost gap
Bottled water usually costs hundreds or even thousands of times more than the same amount of tap water. In the US, tap water typically costs well under a cent per gallon, while bottled water costs from about $1 to several dollars per gallon depending on the brand and pack size.
How the calculator works
- Bottled water per year = daily volume for the household ÷ bottle size × 365 × price per bottle
- Tap water per year = daily volume × 365 at your utility’s price per 1,000 gallons
- Plastic bottles per year = daily volume ÷ bottle size × 365
Check your water bill for the price: utilities charge per 1,000 gallons or per hundred cubic feet (CCF, 748 gallons). Use the water charge only, since drinking water does not change your fixed fees.
Example
Two people drinking 64 fl oz a day each from 16.9 fl oz bottles at $0.40 a bottle spend about $1,100 a year and go through about 2,760 bottles. The same water from the tap costs about $2 a year at $5 per 1,000 gallons.
Is tap water safe?
Public water systems in the US are regulated by the EPA under the Safe Drinking Water Act and must publish an annual water quality report (Consumer Confidence Report). Bottled water is regulated by the FDA as a food. In most places, tap water is safe to drink; concerns are usually local, such as old lead service lines or private wells.
- If your home was built before 1986, ask your utility about lead pipes.
- Private wells should be tested at least once a year for bacteria and nitrates.
- A filter certified to NSF/ANSI standards can improve taste or remove specific contaminants.
Plastic and the environment
Most plastic bottles are not recycled. A 2024 study by Columbia University researchers counted on average about 240,000 tiny plastic particles per liter in bottled water, most of them nanoplastics. Reusable bottles and a filter jug are often the cheapest way to drink well.