Interesting, in reference to the plastic lids:
Snip>
Experts say it all comes down to what type of lid, if any, was on the tank that day.
So far, all investigators will say is that the septic tank itself is underground.
But we don't know if the Thomas's tank, like many Virginia homeowners', has a plastic riser on it, which would make it accessible above ground.
A lightweight plastic lid is usually placed over the rise to cover the tank. The owner of 'Five Star Septic' tells ABC 13 the plastic lid is usually secured with more than 8 screws, which would make it impossible for anyone to uncover. But if the lid is not screwed on, he says even a child could pull the cover off.
As for more traditional septic tanks, like the ones most homes in our area have, the lid itself is actually buried about a foot deep. Dale Wilson, owner of Wilson's Septic Tank Service, says those lids are usually made out of cement and are even difficult for someone of his size to pull off.
"Newer tanks these days are quite a bit thicker than that top, but even that top is almost 100 pounds. There is no way any small person can lift that by himself. No way said Wilson.
http://www.wset.com/story/28635381/...thomas-accidentally-fell-into-the-septic-tank
Its possible that the type of cover on the septic is different than those I am familiar with. I looked up risers that the gentleman was talking about. It can a plastic tubing type thing that makes it easier access than having to dig down. On the top is the lid. Its very possible that the top was not covered with soil or sod. (sorry I very well could have missed if it was or wasn't) Google Septic tank risers.... Her is an example, there are many... Have no idea what the actual cover looks like but, if the septic was like this it would be much easier assessed with out someone seeing messed with like I was thinking prior.
http://aoseptic.com/lidrisers.htm <again just an example...