Sewer Backing Up After Heavy Rain? Here's What That Actually Means
If your drains only misbehave when it rains, that is a specific and diagnosable problem — not bad luck.
What rain does to a sewer line
Sanitary sewers are meant to carry waste water only. Storm water is meant to go elsewhere. When rain gets into the sanitary system, the whole network runs at capacity, and the lowest connected fixture in the lowest connected building becomes the relief point.
Sometimes that building is yours.
The three real causes
1. Infiltration into your own line
Cracks, offset joints or root openings in your lateral let ground water in during rain. Your line, already carrying household waste, cannot handle the extra volume and backs up.
A camera inspection during or shortly after rain shows this clearly — you can see water entering through the defects. That is sewer line repair or lining.
2. A partial blockage that only fails under load
A line with roots or a grease build-up may pass normal household flow fine. Add storm infiltration and it tips over. The clue is that it clears on its own once the rain stops.
Jetting plus a camera pass tells you whether roots, grease or a structural defect is behind it.
3. The city main is surcharged
If the municipal system is over capacity, the backup pressure comes from the street, and nothing wrong with your line will show on camera. This is common in older Louisiana systems where storm and sanitary lines were historically combined.
You cannot fix the city's capacity. You can stop it entering your house.
Backwater valves
A backwater valve installs on your lateral and closes automatically when flow reverses. When the street surcharges, the valve shuts and your house stays clean.
They are the correct answer to cause 3 and worthwhile insurance against 1 and 2. They need occasional inspection to make sure the flap moves freely, which is a five-minute job during any other visit.
If you have had a backup more than once, this is the conversation to have.
What to do while it is happening
- Stop using water in the house entirely. Every flush adds to what is already backing up.
- Keep people and pets out of the affected area. Sewage is a genuine health hazard, not just a mess.
- Photograph everything before cleanup for insurance.
- Call. Emergency backup response runs 24/7 and clearing the line is the first step to everything else.
After it clears — get the camera down
The single most useful thing you can do after a rain backup is inspect the line while the cause is still evident. A line inspected in dry weather three weeks later often looks fine.
Call (833) 435-9778. If rain is in the forecast and you have had this before, call before it starts.