Your house is hookup to two city sewers, one is a 4” to 6” storm sewer line for weeping tile, floor drains, sump pump and sometimes laundry tubs.The other is a 4” to 6” sanitary sewer line for showers, toilets, tubs and sometimes laundry .Both these sewer lines come into your house under the basement floor. When there is a heavy rainstorm the city sewer lines cannot drain away the rain fast enough so the easiest place for the water to go is in your basement, the amount of rain from the storm will dictate the amount of flooding in your basement.

Yes this ninterm system is guaranteed to stop sewer backups or your money back.

No, this is an entirely different design that does not relay on a backflow valve to try to prevent basement flooding.

Backflow valves have a very high failure rate due to mechanical failure such as flapper doors breaking off from very high pressure from the amount of water backing up from the city sewer lines.

Other reasons for backflow valve failures are sometimes items that go down the toilet or other drains in your house get stuck in the way of the flapper door of the backflow valve not letting it close when flood waters are backing up into your basement.

Yes, during a storm if the sewer is backing up from the city sewer line and the backflow valve closes as designed the water you are using in the house such as toilets, showers, laundry etc now can back up into the basement because it cannot get passed the closed backflow valve,so you are flooding your own basement.

Yes 100%

The ninterm system stands for ( no indoor termination ) this means that the sewer lines from the city no longer end/terminate in your house period. Thus not allowing water from the city sewer lines from backing up into your basement it can only drain on the outside of the house causing no damage to your basement.

You can request more information and I will be more than happy to talk to you about the ninterm sewer system.