Bottled water is a luxury

Spending on luxury necessarily reduces one's ability to donate "disposable" income.

A luxury is...

Luxury: something that is an indulgence rather than a necessity.

Drinking bottled water is a choice. It is not a necessity. It is a matter of taste.

We live in the developed world where the water from our tap is more strictly regulated for safety and purity than commercially bottled water. Our water is clean and safe. It meets every real, physical need we might conceive of it.

"Federal regulations dictate the physical characteristics of the city's water, such as turbidity, or muddiness. Provincially, the levels of bacteria, metals and chlorine are monitored. But bottled water is not regulated," Ms. Bailey said. "Tap water must meet requirements and regulations from two levels of government."

Source: http://www.theglobeandmail.com/servlet/story/LAC.20061013.BCWATER13/TPStory/National

Consider That...
Many people in the developing world have no access to even marginally clean water. Often times merely coming in contact with the water there, let alone drinking it, can cause serious disease.

Source of Definition: http://wordnet.princeton.edu/perl/webwn

Lavishness: the quality possessed by something that is excessively expensive

Bottled water is certainly lavish by this definition. Bottled water, which is no different than tap water in its necessary use, can be up to 10,000 times more expensive. That, by any measure, is excessively expensive.

Consider That...
The most prevalent form of water scarcity is economic scarcity. The water exists, but the money needed to access and clean it does not. It is a simple matter of finding the monetary resources necessary to connect people to the water. It is a solvable problem!

Source of Definition: http://wordnet.princeton.edu/perl/webwn

"A luxury good is a good at the highest end of the market in terms of quality and price."

Judged by taste, some would argue that bottle water is a better "quality" product. That is, at best, debatable. Many blind taste tests have shown tap water to be preferred over even the most expensive boutique bottled waters. Still, an advocate of bottled water will claim it is of higher quality, so it may meet that criteria for the purpose of our definition.

We have already addressed price.

Consider That...
By "giving up" this luxury for tap water that is entirely safe and clean, and still great tasting, you could save someone's life. Which is really worth it?

Some might claim that they alone will make little difference, but consider that just $10 will bring life giving water to one person for up to 25 years!

You say your water tastes like stale fish? Then buy a $10 charcoal based filter from the major filter makers. Save money, give life.

Source of Definition: http://en.wikipedia.org/wiki/Luxury