That doesn’t even make sense. Even if there had been work done on the septic tank by someone else, you just don’t reach down and lift the top off those things. It requires the use of a machine at least. Ours is a concrete covering. When it’s pumped out, they use the forks on the whatever machine that use to dig down to the top of the septic tank to lift it off the tank. Who would uncover a septic tank and walk away and leave it open? Someone’s not paying attention.
“”whatever machine that use to dig down””
Correction - THEY USE to dig down....