EP, as well as local township ordinances that could be in play.If the tank is out of service because it is deficient, many local municipalities will require that first it be pumped, they filled with stone and the lid broken to render it non-functional, then graded over and planted like in grass.In each PA  municipality there is an official called the Sewage Enforcement Officer, SEO, contact the township get the name and phone number of the SEO and call him or her for a direct answer to your situation. 

You could also call the local concrete plants / suppliers and ask what they use / recommend.

i actually love the planter and if you stage the house you should have some lush plants in there. that thing is cool!

@Reese Plante we are Flint investors and live just 15 minutes south. 

Looking at buying some multifamily properties, curious on how to organize the lawn and plants upkeep, can you answer these questions, I'd be grateful:1.

A friend of mine has a opportunity to develop a MHP that has a potential park that is zoned, has city sewer and a water treatment plant.

A couple of small shrubs as foundation plantings to replace those yellowish ones that look dead are cheap at Home Depot, and if they die, HD replaces them.  

I’m a firm believer in ‘planting the seed’ and potentially even offering him a low price then walking away.

On the days I have to go into the plant I feel this wave of anxiety that makes me miserable from the time I wake up, to the time I go to bed.

There are no signs of a market slow down anytime soon so I would just plant your flag and be happy to get whatever you can regardless if it's not pretty or looks exactly how you want it.