Septic Field preventing mortgage funding

[Rebecca E.]

Hoping someone can help me give advice to my friend.

She is looking to buy her first house in Wisconsin. It is an old farmhouse in central Wisconsin, currently occupied. As it is in a rural area, it has a septic field, which is inspected and pumped (?) Every three years per local ordinance. There is no obvious problem with the septic field, but the appraiser put in his report "unpermitted " and now the bank is telling her she can't have a mortgage for the property because the field is "unpermitted" and the seller won't replace.

What can she do to save this deal? The appraiser won't change the wording, "I've written that for 30 years and never had a problem so I'm not going to change now"