Keep sending them unenforceable notices of cure/quit and see if they don't get a notion to file suit for your repeated intrusion upon seclusion.

factor that into your expenses because renters won’t do that.Root intrusion can be an issue if you have some old Oaks near the drain field.Impact to city is an option but for a rental, depending on your cash flow of course, probably will take you many many years to recoup.If a potential property has one, definitely have it inspected, checking for damage and cracks in the tank.

I submitted an offer on my first flip today. The main concern I have, and the reason I assume the house hasn't sold yet, is mold in the first floor walls. It is only in four or five spots, and I'm confident that it wo...

I find that overly intrusive and often impractical, as in the case of prospective tenants moving from out of town.I would like to hear suggestions from other BPers on how to screen for tenants who keep a house clean and uncluttered or how to get them to clean up the house before you are showing it to new tenants.

or can this be structured some other less intrusive way?

Yep, water intrusion.

After all, they paid to have that home for that period of time without any intrusion. 

(Fast forward, an expert witness has declared your unit substandard and you have to return 100% of the rent, because there actually was a problem with the heater and it wasn't for whatever reason providing sufficient heat.)The gap under an EXTERIOR door would be a problem in CA, especially if there was water intrusion (probably not on it's own, but combined w/ other problems, it would be a point against you). 

I'm not saying that the law isn't important; I'm just very heavily anti-overly intrusive government, but I suppose that's a different issue.

Major renovations or minor, the tennants shouldnt mind if their getting nice upgrades but how intrusive will it be.