For you and your Parrot, water is the most important thing that is consumed, its intake is crucial to survival. The quality of the water that your Parrot is drinking should be something that is thought about more frequently than it currently is.
Tap vs. Distilled vs. Reverse Osmosis vs. Mineral vs. Bottled
Tap Water: Some water is carried in lead pipes from utility companies to homes and leach from the pipes into your water. The allowed lead levels are 15 ppb. If you have lead pipes coming into your home, you may want to get it tested or simply purchase purified water for drinking. Tap water can also have up to 10 ppb of arsenic in it. Since Guardia and Cryptosporidium are resistant to chlorine they are sometimes found in tap water.
Distilled Water: Distillation strips water of all chemicals and natural trace elements. When these elements are removed from water, it has a PH level of around 5 (acidic). Studies have proven that drinking distilled water, stripped of minerals, can be harmful to you and your Parrot. Long-term consumption of such de-mineralized water can result in mineral deficiencies in the body, however; because of the lack of minerals, it is recommended for misting your Parrot. To make the misting even more enjoyable, you can add pure Aloe Vera Juice to the water [1 ml per 10 ml of water].
Reverse Osmosis: The small pores in the membrane for filtration block particles, like salt, but not the more dangerous chemicals like pesticides, herbicides, and chlorine that are molecularly smaller than water. These chemicals can freely pass through the porous membrane. Reverse Osmosis does remove parasites while still retaining the normal minerals found in water. A Reverse Osmosis unit is available for home use. It is also the most common purification method used by water companies. Something not to forget, regular Reverse Osmosis appliances do NOT remove lead from the water, however there are certain ones that have the added "lead removal" .
Enhanced Mineral Water: The added minerals and trace elements in the enhanced mineral water are actually very hard on your Parrot’s kidneys and liver. Many are flavoured and contain high levels of sugar.
Ordinary Bottled Water: Plastic bottles potentially contain Phthalates, which can leach into the water. The are intended for single use only and for this reason, should never be reused for storing tap or filtered water. There are no strict limitations for the amount of contaminants (ie, E-coli, Arsenic or Phthalates) found in the ordinary bottled water. The manufacturer does not have to list the actual location of where the water came from, or how the water has been treated. It also undergoes less testing then Tap Water.
In short, water that has been purified using Reverse Osmosis is the best choice for you and your Parrot.