In this case, your whole operation is illegal and you would want to remedy it.

You may or may not have been wrong in how you handled it initially, but there will be a fairly painless way to remedy it I’m sure.

Just factor in fixing the reason the basement flooded (could be easy like clogged gutters or extending the down spouts or maybe the sump pump hasn't worked because the electric is off or it could be expensive like digging around the foundation, parging the walls and then adding a french drain or could be real expensive and have a cracked foundation so you need to know) mold remediation and door replacement (if they're really bad) into the renovation figures.  

I didn't want to point out to him that the areas with "flaking paint" looked just like other areas that supposedly didn't have flaking paint because I didn't want him picking new areas for us to re-mediate. 

$89,000 for duplex$1,000 for mold remediation (the original surface mold we saw) and $1,000 for washer and dryer hookup$5,400 for closing and pointsWe would house hack and the other side would rent for $600 paying the mortgage/taxes plus change. 

I'm not sure if we're allowed to recommend companies on here or not, but I have a name of someone I trust that I use for residential and commercial abatement and remediation.  

Studies have been done and that is the average remediation cost.I have had the displeasure of bringing back 7 units from the stench and damage. $5200.

We are going to have to make the first current ($6k) and pay off the taxes ($5k).There are squatters in the house now, but because the house has a code violation and is deemed uninhabitable, we are hoping to be able to get them out quick with a call to the sheriff.Our first order of business is remedying the code violation.

This is a big-ticket asbestos remediation issue if, again, that octopus arrangement is down there and there are open ducts in the floors throughout the building.

Even if I were to pay or help cover the cost of remediation in the home, it would likely re-occur due to source being the neighbor.