We are on a private bore hole and a private sewerage system (both shared with two neighbouring properties, all 3 properties used to be under the same owner until 6 years ago).
Before the property was on a borehole (before we bought it), they were getting water from a spring, the sheep farmer who owned the field behind decided one year to try rearing pigs making the water supply unsafe and that was when the borehole was drilled.
It is totally okay to drink the borehole water as it comes out of the ground, but as the property was previously used as a b&b it had to meet different regs and therefore is filtered, UV filtered and has some "salts" added to balance out the maganese content. Not sure if the same rules apply with spring fed supplies.
Some of our neighbours on springfed supplies have had it dry up in the summer recently. Our borehole, which isn't particularly deep at 25m due to the granite rocks they had to drill it through, was getting very dodgy in summer 2018.
Basically it's fine, until it's not!
We had a problem with the pump over the xmas period a few years ago and couldn't get anyone to come and look at it for about a month (so had 3 houses running on 1/2 bar of pressure, so no washing machines, no showers etc) and obviously the cost of repairs are all ours.
Also worth looking into the sewerage system and if it is working well. If it is all well within your own boundary and not at risk of effecting anyone elses land, then you are unlikely to get pulled up on any problems (according the lovely man from Natural resources wales), but if it needs fixing or replacing the authorites prefer it is replaced with a modern sewage treatment plant, although this is not a legal requirement in the UK yet. These modern systems require a small source of power (there is one that doesn't - biorock) so can take a bit of figuring out when replacing a septic tank &soakaway system.
The cost of this is all on you too. We now have an issue with the drains (leaking rain water, which is overfilling the new sewage treatment plant, so that is going to cost us too (fortunatly shared 3 ways).
Having said all that, I love where we live and wouldn't move.