A sink that drains slow. A shower that pools around your ankles. A backup that keeps coming back after someone already snaked it once. Send a few details and one vetted, licensed San Francisco plumber gives you a straight read, not five companies fighting over your phone number.
Tell us which fixtures are slow, whether it’s one drain or several, and roughly how old the building is. That alone usually says whether you’re looking at a ten-minute clear or something sitting out in the main line.
Where the clog sits tells you what the job is. One slow fixture, a single sink or tub, is almost always a local blockage close to the drain. Hair and soap in a bathroom. Grease and food scraps in a kitchen. Quick to clear. But when several fixtures back up together, or the lowest drain in the building gurgles and rises when you run water upstairs, the trouble has moved out to the main line or the lateral. That is a different diagnosis and a different price. In San Francisco’s older stock the main-line version is common, because the cast iron and clay carrying the whole building’s waste is 70 or 80 years old and narrowing from the inside.
| What you’re seeing | Where it usually is | What actually clears it |
|---|---|---|
| One slow sink or tub | Local clog at the trap or branch | Cable (snake) |
| Kitchen line that re-clogs | Grease coating the pipe wall | Hydro jetting |
| Every low fixture backing up | Main line or lateral | Camera first, then cable or jet |
| Only backs up in heavy rain | Combined-sewer surcharge, not your clog | Backwater valve on the lateral |
| Comes back weeks after each snaking | Roots or a cracked section | Camera the line, repair the joint |
Cabling, jetting, and knowing which
A cable machine clears most local clogs and plenty of main-line ones. It punches through the blockage and drags back hair, roots, and debris. Grease-caked kitchen lines and root-choked laterals are where hydro jetting earns its keep, because it scours the whole pipe wall clean instead of leaving a channel through the muck, so the line stays open far longer. On a main line that keeps backing up, the honest move is to camera it. On aging cast iron the difference between a clog that just needs clearing and a cracked, scaled section that will keep failing is something you want to see, not guess at.
Skip the hardware-store drain chemicals, especially on old cast iron. Caustic cleaner sits on a partial clog and corrodes the pipe from the inside, and it rarely touches a real main-line block. That is how a $200 clear turns into a pipe repair.
The rain test you can run yourself
Does the backup track the weather? A ground-floor drain that only floods during an atmospheric-river storm is often not your clog at all. San Francisco runs a combined sewer: storm runoff and sewage share the same main, and a big storm surcharges it and shoves water back toward the lowest fixture in the building. Snaking that line again does nothing. A backwater valve on the lateral does. If your backups arrive with the rain and leave when it stops, tell us that up front. It changes the whole answer.
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San Francisco drain cleaning questions
One slow drain or the whole house, does it matter?
A lot. One slow fixture is usually a local clog near that drain and a quick clear. Several fixtures backing up at once, or the lowest drain gurgling, points at the main line or lateral. Bigger job, and often the moment to camera the line instead of just cabling it again.
Do drain chemicals work on the city’s old pipe?
Best avoided. On aging cast iron they can do real harm.
Why does mine back up only when it rains?
Because the sewer here is combined, so storm water and sewage move through one main. A heavy storm surcharges it and pushes water back toward your lowest drains. That is not a clog in your line. The usual fix is a backwater valve on the lateral to stop the surge, and it is worth pairing with a camera pass so you know the line itself is sound.
Send your San Francisco drain details
Tell us which drains are slow and how often it happens. You’ll get an honest read on whether this is a quick clear, a jetting job, or a line worth cameraing. No pressure to book.
No cost, no obligation. Just a clear answer from the one vetted, licensed San Francisco plumber who’d actually do the work.