Why Drains Back Up After Heavy South Florida Rain
A drain that works fine on a dry day and gurgles during a downpour is telling you something. The cause may be your pipe, the street or the ground itself. Here is how to sort it out.
Drains gurgling in the rain?
Stop using water, then call and say when it started.
(754) 320-541224/7 emergency lineWhat heavy rain does to the ground
South Florida sits low, and the water table is shallow. When a big storm arrives, the ground fills and groundwater rises. Storm drains and canals take on water, and sewers can slow down when downstream pipes are full.
A storm on April 12 and 13, 2023 dropped a preliminary 25.91 inches at the Fort Lauderdale airport in one day, far above the 14.59 inch record set in 1979. That event showed how much water the ground and the pipes can be asked to handle in a day.
Why your drains react
Three things tend to cause backups during or after heavy rain. Each has a different fix, so it helps to know which one you face.
Groundwater entering cracked pipe
A cracked or open-jointed sewer line lets groundwater leak in. During a storm, the extra water competes with waste for room in the pipe. The line slows or backs up. If your drains behave this way after every big rain, the pipe likely has a defect.
A full public sewer
When the main in the street is overloaded, the flow from your house slows. The backup shows at your lowest fixture, often a floor drain, a tub or a shower. In that case, the problem is partly outside your property.
Roots and old pipe made worse by wet soil
Wet soil lets roots grow and shifts the ground around old clay or cast iron. A line that was marginal on a dry day fails when it is stressed. The storm exposed the weakness, but it did not create it.
Quick checks during a backup
- Stop using waterDo not flush, run laundry or take showers. Every gallon you add can end up on the floor.
- Check which drains reactNote the lowest fixtures first. Several at once point to the main line.
- Look at the cleanoutIf it is full of water, the blockage or the surge is past that point.
- Check the streetLook for water pooling at the curb or a manhole. If so, the public system may be overloaded.
- Call and describe itSay when the problem began and whether rain was falling.
Protect yourself
- Keep children and pets away from any surfaced sewage.
- Wear gloves and wash well after contact.
- Do not use chemical drain cleaner in a backed-up main.
- Take photos of the backup for the plumber and your insurer.
If sewage reaches living space, avoid touching it with bare skin.
Whose problem is it?
The property owner is normally responsible for the lateral, which runs from the house to the connection at the street main. The city or utility owns the main. If the main is overloaded, report the issue to the utility. If the lateral is cracked, it is your repair.
The camera answers the question. A picture of the lateral shows whether groundwater is entering it. See sewer line repair for how that works and what options exist.
| Pattern | Likely cause | First step |
|---|---|---|
| Backup only in heavy rain, clears when it stops | Groundwater or an overloaded main | Camera inspection of the lateral |
| Backup after rain and again on dry days | Roots or a damaged section | Drain cleaning and camera |
| One fixture only | Local clog in that branch | Clear the branch |
| Water in a floor drain at the garage | Main line surge | Stop water use and call |
Fixes that last
If groundwater is entering through a crack, the fix is to repair or line that section. If roots are the issue, clearing them gives relief, and repairing the joint prevents regrowth. When cast iron or clay is failing along a long run, replacement may cost less than repeated service.
Some owners also add a backwater valve, a device that closes when flow reverses. It needs a specific installation and is not right for every house, so ask the plumber whether it makes sense for yours.
What affects the work
- Where the fault sits
- A short repair near the cleanout costs less than a deep one under a driveway.
- Pipe material
- Cast iron, clay and PVC call for different methods.
- Groundwater at the site
- A wet trench slows work and may need pumping.
- Permits
- Repairs and replacements usually need a permit and an inspection.
Ask for the camera video and a written scope before you approve major work.
Neighborhood differences
Elevation and pipe age vary across Broward County. Pompano Beach is low and close to the coast, so the water table and storm drainage matter a great deal there. See Pompano Beach plumbing for local notes. Older streets in Hollywood have more cast iron and clay, which are more prone to cracks and root entry.
What to do during a backup
- Stop running water in the house, including the washer and dishwasher.
- Avoid flushing until the drains settle.
- Keep children and pets away from standing wastewater.
- Photograph any water that reached the floor before you clean.
- Wear gloves and boots if you must handle the area.
Wastewater carries bacteria, so treat any spill as unsanitary. Once the rain stops and the level drops, the drain often recovers. Do not assume the problem is gone. A line that backs up once in a storm will do it again, and a camera visit in dry weather shows why. If you rent or live in a condo, tell the landlord or association the same day. A backup that reaches a shared line may affect other units, and a prompt report keeps the record clear for everyone involved.
Questions people ask before they call
It can be either. A camera on the lateral shows whether the pipe on your property is damaged. If the street main is overloaded, report it to the utility.
It can stop reverse flow from the sewer into the house. It does not fix cracks, and it needs correct installation and maintenance.
Water takes the easiest path out. The lowest fixtures, such as a floor drain or a first-floor shower, are where it appears first.
A plunger on a single fixture is fine. For several fixtures, stop water use and call, because forcing water through a full main can make the backup worse.
Drains backing up after storms?
Describe which fixtures react and when. The dispatcher will explain what a camera visit shows.