Avian vets agree that the one of most common health problems in pet birds is bacterial infections.
Harmful bacteria can be encountered by your bird due to the unsanitary conditions of an un-kept bird cage, but the most common source of bacterial infection can be traced back to the food and water dish.
An open water dish, which I must admit most of us still use, is a breeding ground for bacteria.
Most birds will defecate, and/or dunk their food in an open water dish, and these organic materials feed the bacteria present in the water and cause them to grow even faster.
For that reason, it is imparitive for your bird's health to throughly clean and sanitize the water dish at least twice or more per day. If this is not done, the bacteria will grow, and you bird's health will be at risk when he consumes this contamination.
The problem is, most of us do not have the time to clean water dishes twice or more every day.
There is a solution, however, The Water Bottle. Hamsters drink from a water bottle, and birds are much more intelligent than hamsters. Simply showing them the water bottle, and how it comes out the spout is enough to get them to switch.
You still have to clean and refill the water bottle every day, but without the open water container, you have eliminated a prime source of bacterial infection.