First Deal Financing Hurdles

[Aja Leafe-Hall]

Hi there, I am in a purchase and sales agreement on my first deal. It is a single family home in need of rehab in a rural area. I have been thinking of it as a BRRRR deal. I am using my HELOC for the downpayment and rehab. The owners are willing to finance until the work is done on really nice terms and I just discovered why: I am 2 days from the end of my inspection period and it has just come to my attention that the septic system (lack of info about it) is a reason that the sellers were unable to obtain bank financing. I am out of state and my dad is in NH trying to line up a septic inspection. We had to get an extension already for the inspection period because the house was improperly winterized and needed plumbing repairs before the inspector could go through. The sellers paid for that. Now they are unwilling to give us more time to do the septic inspection, because our closing date is set for two weeks from now. This is my first deal. I did not know a lot about what prevents a bank from financing property. I assumed that the stairways being too steep were the only (fixable) impediment here. I need to be able to refinance for this plan to work, because I am putting equity from my home at risk. Any aDVICE ON HOW TO PROCEED? THANKS