A floor drain in a basement, garage or utility room is often the most accessible opening in a house’s drainage, and it is tempting as a camera entry: lift the grate and the pipe is there. What is there, though, is a trap, then a small branch line, then a connection into the building drain some distance away, and each of those is a limit on what the camera can do. This guide covers what a floor drain entry involves, what it reaches and when it is the right choice.
Quick answer: a floor drain entry inspects the floor drain’s own trap and branch, which is useful in itself, and can reach the building drain where the branch joins it, which may be a few feet or thirty feet away. A standard 23 mm head will not pass most floor drain traps; a small-head drain camera on a flexible rod will pass many. Once in the building drain the camera can often continue toward the main. Use the floor drain to inspect the floor drain, to reach a building drain with no cleanout, or to find out why the basement floods; use a cleanout for the lateral when one exists.
What is under the grate
A bowl or body with a strainer, below it a trap, a U-bend that holds water to block sewer gas, and from the trap a branch line of 2 or 3 in running to the building drain. Some floor drains have a cleanout plug in the body that bypasses the trap; some have a backwater device; some old ones have a bell trap that lifts out. Look before pushing. Inspecting a basement floor drain covers the drain itself in detail.
Removing the grate
Most grates lift out or are held by one or two screws. A grate rusted in place is freed with a little penetrating oil and patience, not a hammer that cracks the body. Note the water level in the trap before anything goes in; a dry trap is a finding. Clean out the sediment in the bowl so the camera does not push it into the trap.
The trap
A floor drain trap is a tight double bend in a 2 or 3 in pipe. A 23 mm head on a 7 mm rod will usually not pass it. A 17 mm or smaller head on a thin flexible rod with a short spring usually will, with rotation and gentle pushes. If the drain body has a cleanout plug beside the bowl, it leads past the trap directly into the branch and is the better entry for any head. Heads for 2 in pipe and bend radius set the limits.
The branch
Past the trap the branch runs under the slab to the building drain. It is small, it may have further bends, and in old houses it is often cast iron that has scaled or channeled. The camera shows its condition, which matters because this branch is the path a backup takes into the room. The distance to the junction is worth noting; it tells the owner where under the floor the branch runs. Reading a floor drain backup covers what the picture may show.
Into the building drain
Where the branch meets the building drain, the camera enters a larger pipe at a wye or tee and can usually be steered downstream toward the main. From here the inspection is a normal lateral inspection, with the distances measured from the floor drain. The head that passed the trap is small for a 4 in drain and will sit low; a skid cannot be fitted through a trap, so the picture is from the floor of the pipe. Rotating to steer helps at the junction.
Reach
The trap and branch use rod, and the small head on a thin rod does not push as far as a 23 mm head on a 7 mm rod. A floor drain entry typically inspects the branch and some tens of feet of building drain; reaching the main is possible on a short lot and unlikely on a long one. State where the camera stopped.
When a floor drain is the right entry
To inspect the floor drain itself, which every basement house should have done. To find the cause of basement flooding, which arrives through this drain. To reach a building drain in a house with no cleanout, as an alternative to pulling a toilet. To inspect a garage or utility drain that may go somewhere unexpected. Basement homes puts it in context.
When it is not
For a full lateral inspection to the main when a cleanout exists; use the cleanout. For a 23 mm head; it will not pass the trap. For a drain whose trap is dry and the room smells of sewer gas; fix the trap seal first and ventilate. Entering from a cleanout is the default.
Equipment
A drain camera with a small head and a flexible rod of 50 to 100 ft, with a sonde if the branch route needs mapping. Small-diameter drain cameras, sewer vs drain camera and a 50 ft drain camera reviewed here cover the class.
Afterwards
Refill the trap with water, replace the grate and clean the camera; a floor drain trap is as contaminated as any sewer. Record the trap condition, the branch condition and distance, and where the camera stopped. Cleaning after a sewage job covers the reel.
Common questions
Can I put a sewer camera down a floor drain?
A small-head drain camera, yes, through the trap and into the branch and often the building drain. A standard 23 mm head will not pass the trap.
How far can a camera go from a floor drain?
Through the branch into the building drain and some tens of feet beyond. Reaching the main is unlikely on most lots.
Is a floor drain a good place to inspect the sewer from?
For the floor drain and the building drain, yes. For the lateral to the main, a cleanout is better.
Related guides
See cameras for drain cleaning contractors, counters vs cable markings, and storm drain push camera inspection.