So essentially, my property would become a hard money lender for me lol.I think it is important to note that this house hack is my only investment property and contains the majority of my wealth.

I've been reading up on the issue and to my understanding all the contamination has been contained/removed. 

The rule is not strictly contained in Rev Proc 2008-16. 

As Courtney mentioned, a problem at a 4plex can potentially affect multiple units (or all of the units), whereas a problem at one house will generally be contained to that one house....along those lines: if a problem occurs at a 4plex (like the electric going out, or a fire), it could affect all of your tenants, but a problem at a house only affects the tenants in that house...However, when you're doing things like tenant viewings, it is easier to only be driving to a single 4plex compared to driving around to four different houses (esp. if those houses are far apart).  ...also, the 4plex might only have one sewer main, one electrical main line, fewer windows/doors, and fewer things to break in general than four separate houses, which could result in lower operating costs...There are a lot of "double edged swords", too; for instance--it may be easier and cheaper to replace a roof on a single 4plex than on four separate houses.

If you are risk averse and have multiple properties, the most conservative way to try to contain the liabilities generated by these assets is to try to compartmentalize them using separate limited liability vehicles.

It seems to me that this specifies that the two units must be contained in a single structure in order to be eligible.

This can contain important information about your title and duties as purchaser.

About a year ago I posted a question about developing a container home in San Diego with a limited budget of $200,000.

Based on the current market and what is likely coming over the next 1-2 years, I highly recommend flipping contain a 1-2 year exit, with a tenant, rather than selling ASAP.

It contains hundreds of files such as ebooks, checklists and spreadsheets for real estate investors: https://www.biggerpockets.com/files 8.Set up keyword alerts to be notified of the topics that interest you: http://www.biggerpockets.com/alertsGood luck investing.