A clogged drain is one of the most common plumbing complaints — and one of the most misunderstood. Most homeowners reach for a bottle of chemical drain cleaner, but that rarely solves the real problem and can actually damage your pipes. Here's what's really causing your clogs.
6 Most Common Causes of Clogged Drains
1. Hair Buildup (Bathroom Drains)
Hair is the #1 cause of bathroom drain clogs. It collects in the drain stopper, binds with soap residue, and gradually forms a dense mat that blocks water flow. Prevention: install a drain screen or hair catcher over every bathroom drain.
2. Grease and Food Waste (Kitchen Drains)
Cooking oil, grease, and fat solidify inside your drain pipes as they cool, coating the inside walls and narrowing the pipe diameter over time. Even "liquid" oils congeal once they hit cool pipe walls. Prevention: never pour grease down the drain — wipe greasy pans with a paper towel first.
3. Tree Root Intrusion (Main Sewer Line)
Tree roots are drawn to the moisture in sewer lines and can enter through tiny cracks or pipe joints. Once inside, they grow rapidly, catching debris and creating complete blockages. This is extremely common in Pomona Valley's mature residential neighborhoods with large shade trees. Signs: multiple drains backing up simultaneously, gurgling toilets, and sewage odors.
4. Mineral Scale Buildup (Hard Water Areas)
Pomona Valley's hard water (15–20 grains per gallon) deposits mineral scale inside your pipes over years, gradually narrowing them. This is especially problematic in galvanized steel and older copper pipes. Hard water scale makes every other clog-causing factor worse by reducing the pipe's internal diameter.
5. Soap Scum and Product Residue
Traditional bar soap contains fats that combine with minerals in hard water to form a waxy residue called "soap scum." This residue coats pipe walls and traps hair and debris. Switching to liquid or synthetic soap reduces soap scum buildup significantly.
6. Deteriorating Pipes
Older homes in Pomona (pre-1970s construction) often have cast-iron drain lines that corrode from the inside out. As the pipe deteriorates, the rough interior surface catches debris and the pipe's effective diameter shrinks. Eventually, these pipes need replacement — patching only delays the inevitable.
When to DIY vs. Call a Plumber
Try These First
- Plunger: Works well for simple toilet and sink clogs. Use a flange plunger for toilets and a flat plunger for sinks.
- Drain screen cleaning: Pull out the bathroom drain stopper and clean it — you'll be amazed what's collected there.
- Boiling water: Pour a kettle of boiling water down the kitchen drain weekly to melt grease buildup.
Call a Professional When
- Multiple drains are backing up at once (sewer line issue)
- The clog keeps coming back despite clearing it
- You hear gurgling sounds from other drains
- There's a sewage smell inside or outside your home
- Water is backing up into your bathtub or shower when you flush the toilet
Why Chemical Drain Cleaners Are a Bad Idea
Chemical drain cleaners (like Drano or Liquid-Plumr) can damage pipes — especially older cast-iron, PVC, and corroded copper. The caustic chemicals generate heat that can soften PVC joints and accelerate corrosion in metal pipes. They also rarely solve the root cause and create a false sense of security while the problem worsens.
Recurring clog? Call 909-764-3214 for professional drain cleaning with video camera inspection to find the real cause.