The first portion of this message was posted by mistake, this is a continuation. The floor drain plug might also cause backups in basement toilets, laundry sinks or other basement drains. None of the homes affected in my town had backups affecting anything besides the basements. After learning about this problem, the only way I would have ever allow a basement toilet in my residence is if there were a highly reliable downstream backup prevention device in place. Otherwise, what would have been most helpful would have been a passive floor drain mechanism which can easily be retrofitted, and that, left in place, would allow the floor drain to work except when back pressure in the sewage line increased, at which point it would close. There is only one product I was able to find after an extensive search using Google, and it was far back in a long series of web pages. The product is "Flood-guard" (R), made by General Pipe Cleaners of McKees Rocks, PA, see their web site at
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, photos and complete explanations available at the site. One of their Flood-Guard devices is a check valve that is rammed into the floor drain opening, then expanded with a stainless steel screw/rubber donut mechanism to hold it in place. There is a float in the center which rises when the downstream pressure does, and blocks backflow. It comes in 2", 3" and 4" sizes. The cost is about $10. Each floor drain would need one of these. The company advises that the check valve device could be popped out of its pipe if the pressure were high enough. In cases like that, they also have a "stand-pipe" model, which uses the same stainless steel screw/rubber donut mechanism, but with a pipe threaded center to allow a standpipe to be screwed into the device. The height of the standpipe determines the amount of protection provided. There are two risks to standpipe use: (1) once the level of pressure pushes the sewage to the top of the standpipe, it will overflow and sewage backflow into the basement will occur. Unless there is an alternate way of draining the basement, such as a sump pump, the backflow cannot drain passively from the basement once the downstream pressure falls. An standpipe which overflows will actually trap any backflow on the basement floor until removed. (2) The height of the standpipe determines the maximum pressure downstream before overflow occurs. Some homeowners' sewer pipes could conceivably rupture under their basement floors, were this to occur. It is hard to conceive that a 3 to 7 foot head of water pressure would cause most commonly used sewer pipes to rupture. The Flood-guard standpipe mechanisms come in 3 and 4 inch sizes. Unfortunately my floor drain opening (the bell of a 4" cast iron sewer pipe of the 1950's) is incompatible with any of the Flood-guard mechanisms - too big for 3" and too small for 4". (End part 2, part 3 to follow)