Understand what your drains are telling you.
A toilet gurgling by itself is one clue. A toilet that gurgles only when the washer drains is a different clue. Map the interaction across your home to narrow down the likely problem zone.
Map the symptom, not just the keyword.
The result is an educational pattern match. It cannot see inside a pipe or replace a camera inspection, pressure test, or licensed on-site diagnosis.
1. What system and area are involved?
Choose the best fit. “Not sure” is okay.
Wastewater system
Primary area
2. What happens?
Select every symptom that applies.
Which fixtures react?
3. What triggers it, and how broad is it?
Trigger
Scope
Lowest drain affected?
4. Safety and recurrence
These answers can override the normal diagnostic flow.
Has this returned after being cleared before?
Safety flags
Your result appears here
We use absolute evidence bands — Strong, Moderate, Lower, or insufficient information — never fake percentages.
High-value diagnostic clusters.
Each guide targets one real homeowner problem and routes back into the whole-home checker.
Toilet gurgles when washer drains
Use the interaction to separate a toilet-only issue from a shared branch or downstream restriction.
Whole homeMultiple drains backing up
Why several affected fixtures change the likely location of the problem.
OdorSewer smell in the house
Trap seal, venting and broader drainage clues — and what not to assume from odor alone.
Lowest drainBasement floor drain backing up
What the lowest drain can reveal about a lateral or sewer backup pattern.
PressureClogged plumbing vent symptoms
Understand why venting can produce gurgling and trap-seal problems without mimicking every sewer clog.
Main lineSigns the main sewer line may be clogged
Use breadth, lowest-fixture behavior and recurrence instead of one symptom in isolation.