Why Does My Sewer Back Up When It Rains?
If your basement drain only acts up during storms, the rain is the clue. The three most common causes of sewer backups after heavy rain, and how to fix each.
If your basement drain only acts up during storms, the rain is the clue. Dry-weather clogs come from what goes down the drain. Wet-weather backups come from water getting in where it shouldn't. We recently had a few calls from homeowners in Hopkins who had sewer backups after several days of rainfall.
1. Groundwater leaking into your line
Older clay and cast iron sewer lines crack and separate at the joints. During a storm, saturated soil pushes water through those openings and your line fills up. Worms or dirt in the line are a giveaway.
2. The city sewer is surcharging
In a big storm, municipal mains can fill past capacity and push water back toward homes. Your floor drain is where it shows up.
3. Illegal tie-ins
A sump pump, gutter or foundation drain connected to the sanitary sewer sends storm water straight into it. Most Twin Cities municipalities prohibit this and some inspect for it. Read more in our guide to inflow and infiltration.
How to fix it
A camera inspection identifies which problem you have. Depending on what we find, the fix could be sealing or lining a leaking line, rerouting a sump pump, or installing a backwater valve that stops city sewage from flowing back into your home.
Book a camera inspection before the next storm.
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