Tap vs. Bottled Water

In this module, we shall investigate the "virtues" of bottled water as well as its similarities and differences with the water you get from your household faucet.

Due to the large difference in price, most people want to know what the difference is between tap and bottled water.  Just how much are Americans willing to pay for bottled water?  In 1990, the average cost of bottled water and vended water in the U.S. was $0.90 per gallon.  This may not seem like a lot to you, but it does when you compare it to the average cost of tap water in California: $0.80 per 500 gallons!

Bottled water can come from wells, springs, artesian wells, or the municipal water supply.  It is regulated as a food product by the U.S. Food and Drug Administration (FDA).  It is important to note that the FDA’s standards are essentially the same as those set by the U.S. Environmental Protection Agency (EPA), which regulates public water supplies.  In some states, however, bottled water requirements are stricter than those for tap water are.  

Click here for definitions of underlined words.

Tap water can come from surface water (lakes or streams) or groundwater.  Unlike bottled water distributors, public water suppliers usually track cases of water-borne illness.  Furthermore, if a contaminant exceeds EPA standards, public water suppliers are required to notify citizens of the contaminant, its level in the water supply, its health effects, and measures that can be taken to prevent illness.  

Lastly, the tap water industry usually employs chlorine disinfection to guard against regrowth or re-entry of microorganisms, which may leave tap water not tasting as good as it would otherwise.  Bottled water, on the other hand, utilizes ozone disinfection, which is tasteless and odorless.

How is bottled water regulated? 

Bottled water was not always standardized.  That is, water bottling companies had the liberty to label their bottled water any way they pleased.  This all changed in 1996 when the FDA set standards that all bottled water companies were required to follow.  Some of the standards included:
 

Is bottled water really healthier than tap water? 

One contributing factor to the popularity of bottled water is that people commonly believe that bottled water is "healthier" than tap water is.  Calcium (Ca) and magnesium (Mg), in particular, are important minerals we would want in our water. Death rates tend to be lower in areas with tap water containing higher levels of Ca and Mg. It has been shown that deficiencies in magnesium are capable of producing heart disturbances, including 215,000 fatal heart attacks in the U.S. each year, and as many as 20,000,000 fatal heart attacks worldwide!  

However, sources say that few brands of bottled water offer a significant amount of minerals.  Below is a comparison of calcium and magnesium in bottled and tap water in a few major cities.  The numbers represented in this table are the percentages of FDA recommended daily intake per liter for adults.
 

Bottled Water Company	%Ca	%Mg	Tap Water	%Ca	%Mg
Crystal Geyser	1	1	San Diego	9	6
Evian	8	6	L.A.	4	4
La Croix	6	6	Houston	4	1
Perrier	9	1	Chicago	4	3
San Pellegrino	20	14	New York	1	0.4
Volvic	1	2	Detroit	3	2

Sources:  FDA; city water department; bottled water companies

From these figures, it can be concluded that bottled and tap water can be equally "healthy" in terms of calcium and magnesium content, depending on where you live.  

What is the difference between the different types of bottled water anyway?

Mineral water, still water, sparkling water, seltzer water and club soda, sterilized water, and distilled or de-mineralized water….  What do all of these have in common?  They are all different types of bottled water.  So what is the difference?

Mineral water is drawn from an underground source and contains at least 250 ppm of dissolved salts.  Whichever minerals are present are what make mineral water what it is.  Some minerals that may appear in mineral water include calcium, iron, and sodium.

Still water is water without the "fizz" caused by gas bubbles.  Ordinary tap water and bottled water in larger containers are examples of still water.
 
Sparkling water is water which is carbonated (contains CO₂, producing the "fizz").  It can either be naturally carbonated or mechanically carbonated in a process where CO₂ is added to normal tap water.

Seltzer water is tap water that has been filtered and carbonated.  Club soda is seltzer water with added mineral salts.

Sterilized water is used to make baby formula and is also drunk by people with immuno-compromised systems.  It must be processed to meet FDA’s requirements for commercial sterility.

Distilled or de-mineralized water is usually tap water that has been treated to remove nearly all minerals and sodium that occur naturally in water.

Bottle Maintenance

"What is bottle maintenance?," you ask.  After all that you know about tap and bottled water now, if you still think you prefer bottled water, it is important for you to take good care of the bottle from which you drink.  Huh?  Bacteria grow best in warm and moist environments.  That means the environment created by an unrefrigerated bottle of water, once the seal has been broken, is the perfect place for bacteria to grow.  This produces a plethora of unwanted health risks.  

Here are some tips for bottle maintenance.  Don’t forget to share them with your friends!

• Wipe the seal with a clean cloth after each use.
• Avoid any type of buildup in the bottle cap.
• If your bottle is refillable, make sure it is well cleaned and rinsed before refilling.  If possible, recycle the old bottle and obtain a fresh, sterile, sealed bottle.

 Back to Top 
 
  

Return to the beginning of the Water Quality unit. 

Return to the Cruising Chemistry homepage.