What is happening
If your drains only misbehave after weather, water is getting into the sanitary line from somewhere it should not.
Drains report problems indirectly. The fixture showing the symptom is often not where the trouble is, which is why the useful first question is not what is blocked but which fixtures are affected and when.
What usually causes it
In this area, four explanations cover most cases:
- Ground water entering through a cracked joint
- A downspout or sump discharging into the sanitary line
- A saturated ground raising the water table around the pipe
- A city main running at capacity during heavy rain
Which one applies changes the fix entirely, and they are not distinguishable from inside the house. We would want to see it before saying anything for certain.
What you can check yourself
Run the fixtures one at a time and note which ones react to each other. Two drains that respond to one another share a pipe, and that narrows things considerably.
Note whether it is getting worse gradually or started suddenly. Gradual usually means the pipe has been closing up for a long time. Sudden usually means something specific is in the way.
Narrowing it down
Keep a note of whether it tracks the weather. If symptoms appear within a day of heavy rain and clear afterwards, water is entering the line from outside, and that is a structural question rather than a blockage.
What guessing costs
Water getting in through a fault also lets soil in, and soil accumulates. Rain-linked symptoms tend to worsen over years rather than staying stable.
When it is worth calling
If it has happened before, it is worth finding the cause rather than clearing it again. A drain that has been opened twice and returned twice will return a third time.
On this particular pattern, sewer camera inspection is the service that most often resolves it, though we would confirm that by looking rather than by assuming.
