Propriety evaluation question

[Garry Martin]

I purchased a two family in August of last year. I rented the second unit two months ago and now I am finding it has a break in the sewer line. I had a propriety inspector go over the place, plus I tested the drains before I made the purchase. To test I flushed the toilet several times while the shower and sink were running (in both units). When flushing I added some paper to insure it would go down. Everything flowed very well.

Once the second family moved in, it increased the load and problems started to surface. The sewer and drain company have identified the problem as a crack/break in the trap where I tie into the rest of the system. They have to dig in a tight space (can’t use heavy equipment) so it will be costly.

This is the second place I have purchased with a major sewer problem. So I am wondering what I am missing or what I can do to better test the system before purchase. The price of the repair will be around 5k. I got a good enough deal so even with the additional cost I will still have positive cash flow. Even if I knew about the problem, I would still have made the purchase. But I would have had it fixed before I rented either of the units. But it would have been nice if I knew about the additional expense before hand.

Does anyone know of a better way to test the sewer system?