Two problems that look alike
Both show up on the basement floor during a storm. They have different causes, different health risks and different fixes.
| Groundwater seepage | Sewer backup | |
|---|---|---|
| What it looks like | Clear or slightly muddy water | Dark, gray or brown water |
| Smell | Musty or none | Sewage |
| Where it enters | Floor-wall joint, cracks, sump pit | Floor drain, toilet, tub, laundry sink |
| When it happens | During and after long rains | During heavy storms, or any time if your line is blocked |
| Main fix | Sump pump, grading, drainage | Backwater valve, sewer line repair |
| Health risk | Low | High: avoid contact |
Why storms hit Clifton basements hard
Surface runoff and brooks. Clifton's hills send runoff downhill fast during intense rain. Weasel Brook, which begins in the Albion section near Ravine Park and runs toward the Passaic River, has flooded parts of Clifton Avenue in severe storms, and the city has worked on drainage projects in that area. The remnants of Hurricane Ida in 2021 flooded buildings along the brook.
River-side groundwater. Blocks near the Passaic River, including parts of Botany Village, Dutch Hill and Lakeview, sit on low ground where the water table rises after long rains.
Older sewer systems. When rainwater gets into sanitary sewers through cracked pipes, manholes and illegal connections like downspouts, the system can surcharge. Pressure in the main pushes sewage back up the lateral into the lowest drain in a connected house.
Fixes for groundwater
- Sump pump sized for your pit and water table, with a check valve and a discharge line that carries water well away from the foundation. See sump pump repair.
- Battery backup pump, because the storms that fill the pit often cut power.
- High-water alarm so you know before the floor is wet.
- Gutters and grading: downspouts extended several feet from the house, and soil sloped away from the foundation.
Fixes for sewer backup
- Camera inspection first to find out whether your own lateral is blocked, cracked or sagging. If the line backs up on dry days, it's almost certainly your pipe. See sewer line repair.
- Backwater valve: a check valve on the lateral that lets sewage leave but closes when the main backs up. It's the standard fix for storm-only backups.
- Disconnect illegal inflow: downspouts or sump pumps tied into the sanitary sewer add to the problem and are generally not allowed.
- Plug or standpipe for floor drains as a temporary measure in some situations.
Who's responsible?
In most New Jersey municipalities, the homeowner is responsible for the sewer lateral from the house to the city main or property-line cleanout, and the city maintains the main. If you suspect the city main is the problem, document each event with dates and photos and contact the City of Clifton's public works department.
What to do during a backup
- Stop using water in the house: no flushing, laundry or showers.
- Avoid contact with sewage, and keep children and pets away.
- Don't run electrical equipment standing in water.
- Call a plumber to clear or assess the line.
- Photograph everything for your insurer. Note that sewer backup coverage is often a separate endorsement.
Frequently asked questions
How can I tell if my basement water is groundwater or sewage?
Groundwater is usually clear and enters at the walls, floor cracks or the sump pit. Sewage is dark, smells, and comes up through the floor drain, toilet or tub. Treat dark water as a health hazard.
Does a sump pump stop sewer backups?
No. A sump pump removes groundwater. Sewer backups need a backwater valve on the sewer lateral or a repair to the lateral itself.
What is a backwater valve?
It's a one-way valve installed on the sewer line that lets wastewater leave the house but closes when the city main backs up. It's the standard fix for backups that happen only during heavy storms.
Who pays for a sewer backup in Clifton?
In most New Jersey towns, the homeowner is responsible for the lateral up to the city main or property-line cleanout. If the city main is the cause, document events and contact the City of Clifton's public works department.
Does insurance cover sewer backups?
Many standard homeowners policies exclude sewer backup unless you have a separate water backup endorsement. Check your policy before storm season.
Why does my floor drain back up only when it rains?
Storm-only backups usually mean the municipal sewer is surcharged by rainwater. A camera inspection confirms your own line is clear, and a backwater valve can prevent future backups.
How do I know if my sump pump is working?
Pour a five-gallon bucket of water slowly into the pit. The pump should start, empty the pit and shut off. If it hums without pumping or doesn't start, have it serviced before the next storm.
Keep reading
- Previous guide: Burst Pipe? What to Do in the First 30 Minutes
- Next guide: Lead and Galvanized Service Lines in Clifton: What PVWC's Program Means for You
- Need it fixed? See our sewer line repair & replacement service in Clifton.