Investor · Worcester, MA · Member since 2020 · 1k+ posts · 1k+ votes
Honestly, there's very little I'll walk away from if the price is right, but I've learned through trial and error to be wary of septic systems since they almost always come with scope creep. Oil spills are the other one I try to avoid entirely. If it's bad enough, that can cost millions to remediate. What's the one inspection finding that's an automatic walk for you, no negotiating?
Foundation and sewer lines are the two I'd put at the top. Both are invisible on a walkthrough and both can swing a flip by $10-15K+. The habit that helps most is pricing the big systems separately before making an offer (roof, HVAC, electrical, plumbing, foundation, exterior, then cosmetics) instead of one lump "rehab number." When each line has a worst-case figure, an inspection surprise shrinks your margin instead of wiping it out.