@Paul O Mahoney - not sure on the inspection costs, but there might be an issue with the two streams on either boundary, in relation to home insurance. I constantly get asked, at renewal time, if the property is within 200meters of a body of water / river / stream. Might be worth checking.
Septic tank will need to have been
registered - if it was inspected (
could be as it's close to the streams), then there should be an inspection report for that. You may need to get an inspection camera into the drain system to make sure it's ok - not covered by standard inspection. Also, there should be some record of the tank being emptied over the years (if applicable), so could look for that from home owners (via the EA). I don't think the standard inspection would cover the septic tank...
Re the water well - the inspection report should detail that - whether it's in good condition / functioning and /or an old system that could do with being replaced etc. Oil tank & pump - again, you should be able to get records of it being serviced and whether it's functioning as expected. Inspection should detail that the radiators / water are being heated when it's on etc, but not much more :-/ if memory serves me right. Also, look for recommendations for inspections. Speaking personally, when I sold my home a few years back, the engineer that came in to inspect my home, did very very little - mostly just a boundary check and a chat about the house with me.
Best of luck with things, and yes, it's definitely a head wrecker