https://www.nytimes.com/wirecutter/reviews/best-under-sink-water-filter/
https://www.amazon.com/dp/B00LC1KRKO/ref=emc_b_5_t?th=1
You would get your main water supply cleaned up with that. For drinking (and the bathroom tap for brushing teeth) you need reverse osmosis, the spruce likes this one: https://www.amazon.com/dp/B09PGX1N3R
Can the average rural resident afford $3k in filters (plus occasional filter changes) if they didn't get paid by the oil companies who fracked nearby? Maybe not. Will this make water drinkable if the taps are literally emitting so much gas they catch fire? Probably not that either, but most people's situations are not that bad, there is just a little contamination not half the water is some volatile organic vapor.
Reverse osmosis removes almost everything that isn't water from how the chemistry works. This is why you are spreading misinformation when you claim "unfilterable". Very few things are like that.
Reverse osmosis has trouble with volatile compounds and some things like chlorine damage the membrane. This is why these systems all prefilter with activated carbon first, which absorbs those well.
The reason tritium actually is basically unfilterable is that it's chemically just hydrogen, bonded with oxygen to form water. So filtering it can't be done via chemistry, you would need to filter based on it's atomic mass. It is possible but it's incredibly expensive and difficult.