Sean is right, sewage pipes are usually ceramic, and should last practically forever, but the wipes snag and then catch other stuff building up to a blockage because they don't rot. The original water mains on the other hand are usually cast iron, probably what makes your water filters turn brown, Zigs. A bit of extra iron probably won't hurt you, it's the things you can't see that you are probably best off without.
We live in a close that runs downhill from the main road and were originally connected to the sewer, but there was not enough drop and it kept backing up, so we now share a septic tank with next door, that's a problem that really should have been foreseen, the drop necessary for drainage is well established.
The Victorians laid most of the cast iron mains, so they have lasted over a 100 years, no wonder they are leaking a bit, they have done very well. Modern MDPE and rigid PVC pipes will probably last even longer, and compared to old style copper and lead piping the MDPE household pipes have no poisonous contamination.
Dad used to say "A good sewage plant manager will drink a glass of the water coming out of his plant" trouble is we are expecting the same plants to cope with a much higher volume of waste, and they just can't cope, we need new reservoirs and new sewage treatment plants building, and it is hard to see how the money could be better spent, water is the basic of basics.