Common Causes of Sewer Blockages

Common Causes of Sewer Blockages

A clear explanation of what actually causes sewer blockages - and why non-dispersing wipes, grease, and foreign objects play the biggest roles.

1. Why Sewer Blockages Happen

Modern sewer systems are designed to transport toilet paper, human waste, and water. Anything else increases the risk of:

• pipe obstructions,
• pump failures,
• fatbergs,
• expensive municipal maintenance.

Understanding the main causes helps consumers make better choices - and helps brands design safer products.

2. Top Causes of Sewer Blockages

1. Non-Flushable Wipes (Baby Wipes, Cosmetic Wipes, Surface Wipes)

This is the #1 cause of wipe-related blockages worldwide.

• They contain plastic fibers (polyester, polypropylene).
• They do not disperse in water - even after hours.
• They behave like cloth and twist around other debris.
• They clog pumps and accumulate in tight pipe bends.

Wastewater authorities consistently state that over 90% of wipes found in sewer blockages are non-flushable wipes.

2. “Flushable” Wipes That Don’t Actually Disperse

Some products are marketed as flushable even though they:

• contain synthetic fibers,
• fail standardized dispersion tests,
• do not break apart under low agitation.

If a wipe does not meet IWSFG, GD4, or PAS 3 standards, it is not truly flushable.

3. Fats, Oils & Grease (“FOG”)

Grease is the silent partner of blockages.

• Hot cooking oil cools and hardens inside pipes.
• It forms a sticky base for wipes and debris to attach to.
• This creates large masses called fatbergs.

Wipes + grease = large blockages.

4. Excessive Toilet Paper Use

Toilet paper is designed to disperse, but overuse can still cause temporary local blockages:

• flushing large wads at once,
• using ultra-thick “quilted” toilet paper,
• combining dry paper with low-flow toilets.

5. Foreign Objects That Should Never Be Flushed

• tampons and sanitary pads,
• cotton swabs and cotton rounds,
• dental floss,
• paper towels and tissues (not designed to disperse),
• hair,
• plastic packaging,
• condoms.

Many of these items create nets that trap wipes and toilet paper.

6. Tree Roots & Pipe Damage

Tree roots naturally seek moisture. If they find a crack in a pipe:

• roots invade the pipe interior,
• debris catches on the roots,
• a blockage slowly forms.

7. Low-Flow Toilets with Poor Pipe Slope

Water-saving toilets use less water per flush. This can reduce the force needed to move wipes or toilet paper through the system.

When combined with incorrect pipe slope, materials can settle instead of moving forward.

3. Why Non-Dispersing Wipes Are the Biggest Problem

Sewer blockages almost always involve items that do not disperse in water:

• plastic-based wipes (baby, cleaning, cosmetic),
• wipes labeled “flushable” but made with synthetics,
• wipes with thermal-bonded plastic webs.

These wipes stay intact and become the “skeleton” that other materials stick to.

4. Why True Flushable Wipes Do Not Cause the Same Problems

Wipes engineered according to IWSFG, GD4, or PAS 3:

• contain no plastic fibers,
• break apart rapidly (>90%+ breakup),
• do not tangle in pumps,
• move through pipes like toilet paper.

These wipes do not persist long enough to form blockages.

5. How Consumers Can Prevent Blockages

Simple rules prevent nearly all wipe-related issues:

• Only flush true flushable wipes that meet recognized standards.
• Never flush baby wipes, makeup wipes, or cleaning wipes.
• Avoid flushing if your plumbing is extremely old or damaged.
• Do not flush wipes together with grease-heavy toilet waste.
• Use 1–3 flushable wipes per flush as recommended.

6. Key Takeaways

• Most blockages come from non-dispersing wipes and grease.
• True flushable wipes behave like advanced toilet paper - not cloth.
• Plastic fibers are the most common cause of wipe-related clogs.
• Only wipes meeting IWSFG, GD4, or PAS 3 are engineered for safe flushing.

Understanding the real causes of blockages helps consumers choose responsibly - and helps build a safer and more sustainable sewer system.