Septic tank at our current house of 14 years has never been inspected and we have no plans to do it.
Prior house of 20 years same thing.
Houses before that were on city sewage so Not Applicable.
Grew up in the country with a septic tank from 1965 to 1973. Never had an inspection.
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So if I was selling a home and the buyer wanted an inspection of a perfectly functioning septic system, I would offer that he do it at his own expense. I don't think a buyer's due diligence is
my expense. If a problem is discovered, I would reimburse the inspection cost and pay for a proper repair.
If he did not want to pay for the inspection, I'd offer to pay for any work needed within the first year. If it had a problem it would surface during the first year.
If that isn't good enough, then the buyer could keep looking.