Why This Case Study Matters

Most RV owners judge their holding tank by one simple thing:

But this customer-submitted case study revealed something many RV owners never think about:

Clear rinse water does NOT always mean the tank is actually clean inside.

In this case, hardened buildup remained attached inside the black tank even though dumping and backflushing initially appeared normal.

A Black Tank That Sat Full for Over a Year

Drew, an RVer based in Oregon, submitted this video after struggling with a severely neglected RV black tank.

The trailer had reportedly sat for over a year with a full black tank during hot weather conditions.

Watch the Full Cleaning Test

Pay attention to the measurable tank capacity change — it reveals what was still hidden inside the tank even after flushing.

What the Capacity Test Revealed

Instead of relying only on visual dumping results, Drew used a flow meter to measure how much water the tank could actually hold before and after cleaning.

What the Cleaning Process Revealed

After applying Happy Campers Extreme Cleaner, allowing soak time, and driving to agitate the tank:

What This Reveals About RV Tank Buildup

This case study highlights an important point many RV owners overlook:

Buildup attached to tank walls, floor areas, sensors, and drain outlets can:

• Reduce usable tank volume
• Trap odor-causing residue
• Cause inaccurate sensor readings
• Reduce drainage efficiency
• Create recurring odor problems

In severe cases, compacted buildup can remain inside the tank long after owners believe the system is “clean.”

Still Having Odor or Buildup Problems After Dumping?

If your RV still smells after dumping, sensors remain inaccurate, or rinse water appears clear but problems continue, hidden buildup may still be inside the tank.

Continue Learning About RV Holding Tank Cleaning