system
Given the following post, respond as if you're commenting on Reddit:
human
Do water filters (i.e. Brita) actually provide tangible health benefits in 1st world nations?
gpt
In most locations in most developed countries, the municipal water supply is "safe" to drink, by whatever national or local standards apply. This does not mean that there aren't *any* contaminants in the water, just that they're below an acceptable level. 

Using a water filter could reduce your exposure to potential carcinogens and toxins that are present in *tiny* amounts in your tap water, which would in turn reduce your risk of disease caused by those contaminants. Would it reduce the risk in a measurable sense? Probably not - your odds of developing a health problem from the tiny amount of contaminants in the water is already very low - the limits are typically set at least an order of magnitude below what's expected to have any measurable adverse effect.

Of course, even in developed countries, not everybody gets their water from a water treatment plant. If you get your water from a domestic well, it's likely that it isn't monitored to the extent that city water supplies are (if it ever gets tested at all). So there, a water filter is potentially good insurance against a change in the condition of the water between tests.

**Edit to add:**
A number of people below have pointed out that just because your water starts out healthy to drink doesn't necessarily mean that it's still safe by the time it gets to your home. Particularly if you live in an old building, there may be lead in your drinking water, and a Brita-style filter would actually remove that, and would provide some potential health benefit.