Read the pattern
Signs that point past simple buildup
Gurgling, odors that keep returning, water rising in a shower when a toilet is flushed or a backup soon after cleaning can all mean the restriction is more than buildup. Several drains slowing at once can suggest a problem in a shared or main line.
These signs justify a closer look; they do not identify the cause on their own. Grease, hair and soap residue are common culprits, but tree roots entering an underground line, a cracked pipe or a section that has sagged or collapsed can produce similar symptoms.
