Clog or broken sewer line?
Ranks the likely causes from what you're seeing, and separates the cheap, local problems from a broken pipe and from a problem in the public sewer.
The short answer
A clog and a broken sewer line can look identical from inside the house. The clues that separate them are how many drains are affected, whether the problem returns after clearing, what's on the drain cable, and what you see outdoors over the line. Tick the symptoms below; nothing you enter leaves your browser.
Tick a symptom to see what usually causes it, ranked — with the cheap, local causes separated from a broken pipe and from a problem in the public sewer.
Single symptoms and their most likely cause
What the checker ranks first for each symptom on its own. Combining symptoms changes the answer — two or three together are much more telling than one.
| Symptom | Most likely cause | Where the fault sits |
|---|---|---|
| Only one drain is slow or blocked | A clog in one fixture's drain | One fixture's drain |
| Several drains are slow at the same time | A clog in the main sewer line | Main drain (a clog) |
| Water comes up at the lowest drain | A clog in the main sewer line | Main drain (a clog) |
| Toilet or drains gurgle | A clog in the main sewer line | Main drain (a clog) |
| Backs up when the washer drains or a toilet flushes | A clog in the main sewer line | Main drain (a clog) |
| The clog keeps coming back | Tree roots growing into the line | Your sewer lateral (the pipe itself) |
| Roots came out on the snake | Tree roots growing into the line | Your sewer lateral (the pipe itself) |
| Sewage smell through the house | A dry trap, failed wax ring or blocked vent | Traps, seals or venting |
| Smell in one room only | A dry trap, failed wax ring or blocked vent | Traps, seals or venting |
| Soggy patch, sinkhole or sewage smell in the yard | A broken or collapsed section | Your sewer lateral (the pipe itself) |
| A strip of greener, faster-growing grass | A broken or collapsed section | Your sewer lateral (the pipe itself) |
| It only happens during or after heavy rain | A blockage or overload in the public sewer | The public sewer |
| Neighbors have the same problem right now | A blockage or overload in the public sewer | The public sewer |
| Rats, roaches or flies coming from drains | A broken or collapsed section | Your sewer lateral (the pipe itself) |
How the checker ranks causes
Each cause is scored by how strongly it explains each symptom, and the scores are combined across everything you tick. The weights are deliberately conservative about the expensive answer: a dry trap or a single-fixture clog outranks a broken sewer line unless the evidence points outside the house — wet ground, lush grass over the line, pests, or a clog that returns.
It also watches for combinations that change the first call you should make. Neighbors affected at the same time send you to the sewer utility before a plumber, because the public main is the likely cause and clearing it costs you nothing. Wet ground over the line together with drainage problems inside flags a likely break.
What this can't tell you
No symptom checker can see inside a pipe. It narrows the likely causes so you spend money in the right order — refill traps, clear the line, then inspect — but only a camera inspection confirms a break, a belly, roots or the pipe material. If sewage is coming into the house, deal with that first: stop water use and keep people away from it.
Frequently asked questions
- How can I tell if my sewer line is broken or just clogged?
- A clog clears when the line is cabled and stays clear for a long time. A broken line blocks again quickly, the cable stops at the same point, and there are often outdoor signs — wet ground, a depression, lush grass or sewage smell over the line. A camera inspection confirms it.
- What are the signs of a broken sewer line?
- Recurring clogs across several drains, sewage smell in the basement or yard, wet or sunken ground and unusually green grass over the line, pests coming up floor drains, and backups at the lowest drain in the house.
- Should I call a plumber or the city?
- Call the sewer utility first if neighbors have the same problem at the same time or it's happening in heavy rain. Call a plumber if only your house is affected.
- Is my information stored?
- No. The checker runs entirely in your browser and nothing you tick is sent anywhere.