My house was newly built less than 2 years ago and recently 2 of 4 sinks have started having a terrible sewer smell. I first thought they just needed cleaning/drain-o (also I thought of p-trap), but I noticed a common denominator. The 2 sinks that smell have a configuration like this (notice the extra black line):
The other 2 that don't smell don't have that black line, just the hot, cold, and drain lines. What is that black line and is this smell attributed to it? How do I get rid of this smell?
The other 2 that don't smell don't have that black line, just the hot, cold, and drain lines. What is that black line and is this smell attributed to it? How do I get rid of this smell?