Metal Water Bottles
There are several types of metal water bottles that can be found on the market today, and we will try to explain each with all of their advantages and disadvantages. Overall, you will find that there are many more reason why to use a metal water bottle than not to.
Stainless Steel Water Bottles
Stainless steel water bottles are by far the most durable out of the metal water bottles available on the market, but you have to be careful which type of stainless steel water bottle you are buying. There are 2 major types that I have found online for sale, and there is a big difference between them.
304 Stainless Steel
304 stainless steel is the main type of stainless steel I have seen used for the manufacturing of stainless steel water bottles. 304 stainless is used in most kitchen applications, and is also known as food grade stainless steel. You want to buy 304 stainless steel water bottles when you have the money, and will be using your water bottle for more than just water. 304 stainless steel is very resistant to corrosion, and your stainless steel water bottle will be able to hold many drinks without corroding your bottle. As an overall all-purpose bottle for water and more, the 304 stainless is definitely your best bet and will hold off corrosion for a very long time.
201 Stainless Steel
The other option that I have found online is 201 stainless steel. This is not a food grade stainless steel, and seems to be more of a water grade stainless steel from the research I have done. 201 stainless steel is used in city water storage tanks and similar applications with water only. It is more likely that 201 stainless will corrode with acidic drinks and possibly others, as it will interact differently with the metal alloy combination for this particular type of stainless steel. These bottles are usually found to be around 1/2 the price of 304 stainless steel bottles, but as they say, you get what you pay for. 201 stainless might be great for using just for water, but as an all purpose reusable bottle, it might not be a great choice.
Aluminum Water Bottles
Aluminum water bottles are another alternative to plastic, yet have an inherit problem of easily corroding due to the fact that aluminum corrodes much easier than stainless steel.
Sigg Water Bottles
Sigg water bottles are coated with a resin of some sort, which just recently was found to have the harmful chemical BPA in it. For years Sigg promoted their aluminum water bottle with the resin compound as being BPA free, but a recent study found that their resin did in fact contain amounts of BPA. They are by far the most popular water bottle maker in the world, so they have the money to keep this sort of information quiet, and out of the way of consumers. Supposedly they have fixed this so called oversight, but the largest global brand has been tarnished so to speak.
Though several health agencies in the US find that BPA is not harmful, it is basically a known fact that chemicals not naturally found in the human body can have harmful and possibly deadly effects on people that come in contact with them. Even something like a strawberry can be deadly to the right person, so I can be certain that harmful chemicals can do much worse over time to anyone.