A water cistern can become contaminated and if you rent to tenants lots of liability there just like with well water and constant testing.

What would you do if your well went bad and the groundwater became contaminated?

Unless you are trained and certified in safe remediation techniques, taking your own measurements with a moisture meter is pretty useless and self diagnosis and removal of materials that are suspected to be contaminated is a bad idea.

I don't know the rules in that area but it might be good protection for you to get your tenant out of the property and put them up in a hotel because there is so much that can put you at great risk with a flood, instances are (contaminated water, electrical current in the water that hasn't been identified, and of course the risk of mold or other air born contaminates) that might affect someone living in the home.

Let's say you get your way, that anything goes as you believe so long as it doesn't "hurt" anyone else.That would mean you can have a tenant that puts on the red light and has strangers over at all hours going through your building, that would be okay so long as they were quiet and didn't hurt anyone.It also means that your tenants could legally sit inside and smoke crack, getting high and contaminating the unit, after all, it would be perfectly leagl.

Maybe you'll try to hide meth contamination?  

It also contaminated the whole unit.

Have a professional cleaning crew clean up the crime scene area, contaminated rooms, just as an added piece of mind for the new owners.

One that is free and clear and protected from ALL liability, and another (with NO cross contamination) that is highly leveraged, and holds all your risks.

Chris I meant Clay pipes but different parts of the country used different things during different eras because of cost,availability,closeness to the area where constructing,soil conditions,etc.Either way in my mind a critical inspection is to scope the line all the way out to the street.Some plumbers only have a 25 ft camera and others have the big one that goes hundreds of feet which will reach out to almost all mains at the street before running out of camera line.On environmental stuff mentioned you sure can have situations where next door is a laundry facility or gas station that is now vacant.The contaminants leach over into your soil.Now the EPA is demanding you clean it up which becomes very,very expensive.What to look for comes with experience.I have found it is better that I learn from my plumbers and other professionals I use and they often share tips for free.Here in Georgia inspectors do not have to be licensed (it might have changed recently)but in the past they were not required to be.I have found I have more knowledge than many inspectors and all they do is charge a bunch of money and then refer you off to the people I have already learned from.My guys will take a look at it for free because they know it is future business I will be giving them.I just call them in if I have a question.