Our house got a clog in the main line to the street. We only noticed it after a few showers and toilet flushes caused water to back up through a floor drain in our utility room. We would like to prevent this from happening in the future if possible. After searching this forum a bit I saw a post with a link to Flood Guard for floor drains (http://www.plumbingsupply.com/floodguard.html). However I've found many people online saying that these were not effective. Are these an effective solution and/or the best solution? Also, if I installed this and a similar backup did occur what would be the best way to detect it? My next lowest drain is a bath tub in a guest bath that is rarely used.
I'm less concerned about a sewer system backup because while the rear of our house is below grade, the front is completely above grade and the front yard slopes down to the street. But maybe I should also be concerned about that?