We bought a house 7 months ago and since 4 months the toilet would overflow if we use the wash machine, the dish washer or the sink in the kitchen or bathroom. I would see the lint from the washer and I would see the food from our garbage disposal. Also to mention is that it is an old house from the late 70's and it is galvanized pipes. Is it smart to clean them or easier to replace them with plastic pipes?
And if to clean, how?