Many. But not all of them filter the same particles, nor with the same level of safety, and nor do they provide the water your body needs.
- Active carbon. Effective for eliminating chlorine, which is responsible for unpleasant smells and tastes. Not much more. It’s as simple as it is economical. But if you’re not going to do the cleaning and maintenance properly, it’s better to drink from the tap.
- Reverse osmosis. This includes active carbon, among other things. This is effective for eliminating ABSOLUTELY everything other than H2O from the water. These always include postfilters which add the minerals our body needs back into the filtered water.