A drain usually keeps clogging because the first fix only opened a small hole through the blockage, leaving buildup on the pipe walls. Other common reasons are a deeper clog in the branch or main line, roots, a sag or damaged section in the pipe, a venting problem, or habits that keep sending grease, hair or wipes down the drain.
The 8 most common reasons drains re-clog
1. The clog was only partly cleared
Plungers and small snakes often punch a hole through a clog instead of removing it. The remaining material catches debris again. Cleaning the full pipe diameter, with a larger cable or hydro jetting, is the fix.
2. Grease coating in kitchen lines
Grease cools and sticks to the pipe walls, narrowing the pipe a little more each time. See kitchen sink drain cleaning.
3. Hair and soap in bathroom drains
Hair wraps around stoppers and binds with soap scum. Regular stopper cleaning and hair catchers make a big difference.
4. The real clog is further down
If a branch or main line is partly blocked, the drains above it will keep slowing down no matter how many times the fixture is cleared.
5. Tree roots in the sewer lateral
Roots enter through small gaps and grow back after being cut. Common in established neighborhoods with mature trees.
6. A sag, offset or damaged pipe
Low spots hold water and waste; shifted joints catch paper. A camera inspection shows these.
7. Venting problems
Plumbing vents let air into the system so water flows smoothly. A blocked vent can cause slow drains and gurgling even when the pipe is open.
8. What goes down the drain
Wipes, paper towels, coffee grounds, eggshells and cooking oil are the usual suspects.
What you can do yourself
- Clean bathroom stoppers and shower strainers regularly.
- Use strainers and hair catchers.
- Keep grease and wipes out of drains.
- Remove and clean a sink P-trap (with a bucket underneath).
When to call
Call when the same drain clogs again within a few weeks, when several drains are slow, or when you see water come up in a different fixture. Those are signs the problem is beyond the fixture. See clogged drain repair.
Not sure which drain service you need? Describe the problem and we'll point you in the right direction.
Call (562) 245-5818Frequently asked questions
Do chemical drain cleaners stop drains from clogging?
They may dissolve part of a clog but do not clean the pipe thoroughly, and some can harm older pipes and are hazardous to handle.
How do I know if roots are in my sewer line?
Repeat main line clogs in a home with mature trees are a common hint. A camera inspection confirms it.
Related services
Clogged Drain Repair
Help for slow, fully blocked and recurring clogs, from finding the cause to clearing the line.
Learn MoreDrain Camera Inspection
Video inspection to see roots, breaks, sags and buildup inside drain and sewer lines.
Learn MoreMore drain guides
- Whittier Sewer Lateral Guide: Who Is Responsible for Your Sewer Line?
- 7 Signs Your Main Sewer Line Is Clogged, Not Just One Drain
- Hydro Jetting vs. Drain Snaking: Which One Does Your Drain Need?
- Drain or Toilet Backing Up? What to Do Right Now
This guide is general information, not legal or engineering advice. Rules and agency contacts can change; confirm details with the City of Whittier or Los Angeles County Public Works.