If you’ve been RVing for any length of time, you’ve likely encountered the dreaded clogged black tank. RV toilets connect directly to holding tanks, not a sewer line like residential toilets. This unique plumbing design makes them prone to getting clogged, especially if proper maintenance isn’t followed. Don’t worry – with the right techniques and tools, you can get your RV toilet flushing freely again.
Why RV Toilets Clog More Easily
RV toilets differ from household toilets in a few key ways that make them prone to clogs:
- Direct connection to holding tank – Rather than flushing to a sewer line, RV toilets empty directly into the black water holding tank. Without the more powerful flush of a residential toilet, waste can build up on tank walls.
- Specialized toilet paper – RV toilet paper breaks down faster but doesn’t have as much “grab” to clear piping. Regular toilet paper will clog tanks quickly.
- Foot pedals vs handles – Pedals on RV toilets push up a seal to open the valve. If debris gets lodged here, the valve can’t open fully.
Following proper use and maintenance is crucial to avoid clogged tanks and unclog an RV toilet when needed.
Diagnosing an RV Toilet Clog
How can you tell if your RV toilet is clogged? Here are some common signs:
- Water backs up and gurgles when flushing
- Toilet seems sluggish and slow to drain
- Flush pedal requires more force to push down
- Toilet paper or waste get caught in seal/valve
An RV toilet clog can occur in two places – either in the seal/valve or down in the black water tank itself. To unclog an RV toilet, you’ll need to diagnose where the clog is happening.
Checking the Valve/Seal for Clogs
Clogs in the seal or valve are common due to how RV toilets are designed. Pushing the flush pedal raises the seal so waste can enter the holding tank. If debris gets caught here, it prevents the seal from rising fully, blocking water flow.
To diagnose a seal clog:
- Flush the toilet and observe if water backs up or drains slowly
- Check if toilet paper or waste get stuck around the valve opening
- Use a small mirror to visually inspect the seal/valve area
Inspecting the Tank for Clogs
While seal clogs are more common, debris can also build up and clog your black tank. Waste forms pyramids and mounds when the valve isn’t closed properly between flushes. Tank clogs require more work to dissolve and flush out.
To check for tank clogs:
- Use a tank camera to visually inspect the inside of the black tank
- Flush colored toilet tabs and check if they flow freely through the toilet
- Feel along the tank with a broom handle and see if you hit any hard areas
Once you’ve diagnosed the clog location, it’s time to tackle that clog head-on.
Unclogging a Seal or Valve Clog
For seal clogs, a combination of manual and chemical techniques work best to unclog an RV toilet. Here’s a step-by-step process:
- Turn off the water supply valve and flush the toilet to drain as much water as possible. This prevents splashing when plunged.
- Use an RV toilet seal cleaning wand or plunger to vigorously plunge the valve opening. Angle the wand slightly to better dislodge any debris.
- Flush the toilet again – the pressure should push out any loosened waste in the seal/valve area.
- If flushing doesn’t clear the clog, use a thin stick or valve cleaning pick to manually dislodge solids blocking the valve. Twist the stick to break up or hook debris.
- Once the clog is cleared, flush several more times to wash any remaining particles down the tank. Then add a dose of RV holding tank cleaner to help break down any residue.
With some patience, you can clear even stubborn seal clogs. Just take care not to damage the valve seal when using sticks or other tools.
Tackling Clogged Black Water Tanks
Blockages down in the tank require a more involved process to fully unclog an RV toilet. Here are tips:
- Use a flexible 4-6 foot PEX pipe to vigorously plunge and poke holes in the clog. Angle the pipe across different areas of the tank to break up waste.
- Pour in RV black tank cleaner/deodorizer and fill tank completely with water. Let sit for 24-48 hours so chemicals can dissolve solids.
- After time to work, open the black tank valve and thoroughly flush the toilet. Repeat as needed to wash all debris down the sewer hose.
- Consider adding a tank rinser like a Tornado or other gadget to power wash the inside of the tank.
- Finish by treating your black tank with a commercial cleaner again and let soak before flushing.
It can take repeated flushing and soak cycles to fully clear out a serious black tank clog. But a thorough approach helps prevent clogs from returning later.

Preventing Future RV Toilet Clogs
While occasional clogs are likely if you RV often, you can take steps to reduce their frequency:
- Use specific RV toilet paper – Regular household TP will clog tanks fast. Use rapidly dissolving RV toilet paper.
- Close black tank valve after flushing – Leaving the valve open allows pyramids of waste to form. Close it between flushes.
- Use tank cleaning chemicals – Treat your tank regularly with RV black tank deodorizers and cleaning agents.
- Do deep cleanings – Periodically flush, fill, and soak your tank to remove stuck-on gunk.
- Install a backflow preventer – These devices stop backflow if hooked up to city sewer lines incorrectly.
- Avoid flushing wipes or paper towels – Anything other than RV TP is asking for clog trouble.
With proper usage and care, your RV toilet can keep flowing smoothly for seasons to come. No one wants to deal with unpleasant clogs while trying to enjoy camping. Follow these tips to unclog an RV toilet quickly and prevent repeat blockages.
Key Products to Help Unclog and Maintain Your RV Toilet
- Plunger/Seal Cleaning Wand – Designed to plunge RV valve openings and dislodge clogs.
- 4-6 foot Flexible PEX Pipe – For snaking and poking holes in tank clogs from the toilet.
- RV Holding Tank Cleaner/Deodorizer – Breaks down waste and cleans tanks to help prevent future clogs. Look for enzymes to dissolve solids.
- Clear RV Sewer Hose – Allows you to see when dumped waste has cleared from the hose, avoiding backups.
Regular maintenance cleaning and using the right gear goes a long way towards headache-free RV plumbing. Don’t let a clogged black tank ruin your camping trips. Follow these tips and you’ll be ready to tackle toilet clogs quickly while on the road.