How To Fix an RV Toilet

MANY OF US will eventually need to fix our RV toilet. Maybe it’s just a bit wobbly, or the bowl no longer holds water—or you may face a significant leak or clog. Whether you need to repair an RV toilet leak, replace a worn seal, unclog a stubborn line, or fix a broken foot pedal, this guide will help you safely and confidently fix an RV toilet.

Key Takeaways

• Common RV toilet problems include water not holding, clogs, leaks, wobbling, odors, and foot pedal failures. Find step-by-step fixes for each below.
• Learn when to replace seals, tighten bolts, lubricate components, or perform deeper repairs, plus brand-specific notes for Dometic and Thetford models.
• Use good prevention to avoid future issues: never leave the black tank valve open, and always add water and tank treatment after dumping.

Common Problems With RV Toilets + How To Fix Them

Let’s break down the most common RV toilet problems—and how to fix each one.

RV Toilet Won’t Hold Water (Bad Seal or Ball Valve)

When the bowl won’t retain water, the most common failure point is the flush ball seal. Over time, those rubber seals dry out, crack, or accumulate debris, preventing a full and watertight seal. You’ll usually notice the bowl slowly draining after filling, with the water level refusing to stay above the ball valve, a faint hiss or bubbling around the seal, or a foot pedal that doesn’t allow the ball to fully close—classic signs that the seal is worn or dirty.

How To Fix an RV Toilet Seal

Follow these steps to remedy the issue:

1. Turn off the water supply to the toilet.
2. Press the foot pedal to open the ball valve.
3. Clean the seal with a soft brush and mild cleaner to remove buildup.
4. Apply a toilet seal lubricant and conditioner to re-lubricate the seal.
5. If the leak persists, replace the seal entirely.

Use these guides to replace a flush ball seal in these common RV toilet brands:

• Dometic
• Thetford

RV Toilet Foot Pedal Doesn’t Work or Feels Stiff

If flushing feels crunchy, sticky, or doesn’t activate water flow, the foot pedal linkage may be damaged or disconnected.

How To Fix an RV Toilet Foot Pedal

Follow these steps to remedy the issue:

1. Shut off the water to the toilet.
2. Remove the shroud around the toilet base (usually a few screws).
3. Inspect for broken springs, rods, or plastic connectors.
4. Lubricate hinges and moving parts.
5. Replace broken parts or swap the entire pedal assembly if necessary.

Technician Tip: You may need to contact the toilet manufacturer directly for replacement parts. 

RV Toilet Won’t Flush or Seems Clogged

Toilets clog more easily in RVs due to narrower plumbing and holding tank design—especially if you don’t use RV-safe toilet paper or don’t flush with enough water. Common signs include slow or weak flushing, water rising higher in the bowl than normal, or a partial flush that leaves waste behind.

How To Fix a Clogged RV Toilet

Here are some methods to unclog an RV toilet:

• Open the ball valve and pour 5-10 gallons of hot (not boiling) water—mixed with a quart of tank chemical to dissolve built-up solids—down the toilet. Let it sit 8–12 hours.
• Add ice + water, drive around, and let the movement break the debris loose.
• Treat the tank with the same RV-safe tank treatments you normally use.
• Use your built-in black tank flush or a flexible tank wand if needed.

Read our complete guide on How To Unclog RV Black Tanks.

RV Toilet Leaks at the Base or Underneath

A leaky RV toilet often points to a failed flange seal, loose mounting bolts, or cracks in the base. Some leaks are more noticeable than others, ranging from occasional drips around the base to steady moisture pooling on the floor or a persistent musty smell that shows water is escaping somewhere it shouldn’t.

How To Fix a Leaking RV Toilet

Follow these steps to remedy the issue:

1. Shut off the water and drain the bowl.
2. Disconnect the water line from the back of the toilet.
3. Loosen mounting bolts at the base—carefully to avoid cracking.
4. Remove the toilet base.
5. Inspect the flange seal for flattening or cracks.
6. Replace the seal if water continues escaping. Ensure you use a compatible replacement seal for your toilet model.
7. Check the water line fittings for drips.

Consult our RV toilet flange seal replacement guide for further assistance.

Toilet Wobbles or Shifts While Sitting on It

A rocking RV toilet almost always means the floor flange bolts are loose or the base gasket is worn out.

How To Fix a Wobbly RV Toilet

Follow these steps to remedy the issue:

1. Turn off the water and disconnect the supply line.
2. Loosen the toilet base and lift the toilet to expose the floor flange.
3. Remove bolt caps and tighten hardware evenly until snug. Avoid overtightening, as it can crack the floor flange.
4. Test for wobbling. If fixed, re-anchor the toilet and reconnect the water.
5. Remove the toilet and replace the foam or rubber base gasket if rocking persists.

Sewer Smell Coming From the Toilet

If you notice foul odors, you may need to improve seal lubrication, clean the valve, or perform a deep treatment of your black tank.

RV Toilet Smell Fix

Here are some methods to fix a smelly RV toilet:

• Lubricate the bowl seal with RV-safe seal conditioner.
• Use RV-safe toilet paper only.
• Treat the black water tank with your go-to holding tank chemicals.
• Check roof siphon vents for blockages.
• Check the toilet’s vacuum breaker for tank fume leakage, if so equipped.

Learn more about how RV plumbing works.

Brand-Specific Fixes for Dometic & Thetford Toilets

Dometic and Thetford are two of the most common manufacturers of RV toilets. Luckily, fixing a Thetford or Dometic RV toilet typically follows the same steps outlined above. These toilets share similar mechanics, so sealing, flushing, pedal, and valve fixes apply to both. Just confirm your model number before buying replacement toilet parts.

Technician Tip: The model number can typically be found on the base of the toilet. There are several numbers on the tag, and all are important to ensure you receive the exact parts for your model. Therefore, take a clear picture of the tag for your parts representative.

When to Call a Professional

If you’re confident, fixing an RV toilet can be a straightforward process. But if water damage, odor issues, or deep clogs push past your comfort level, don’t risk it. Sewer repairs can get smelly and messy fast.

If you’d rather not spend your afternoon elbow-deep in your black tank, let the pros handle it. Schedule service at your local Camping World for leak repairs, seal replacements, clog removal, and full toilet rebuild or replacement. Quick, clean, and done right—no mess, no smell, no stress.

How To Prevent (Most) RV Toilet Fixes

Luckily, there are two habits you can pick up that will help you avoid most of these toilet issues: 

1. NEVER camp with the black tank valve open so it constantly drains through the hose and into the dump station. If you do this, the water runs away immediately, but the solids stay behind and build up quickly. Additionally, since an RV toilet lacks a water trap, odors from the dump station and built-up solids in the tank can escape through the toilet into the RV and out through the rooftop vent, contaminating the campground with unpleasant smells.

2. ALWAYS add 2-5 gallons of water through the toilet and into the black tank before camping and after dumping the tank—along with your favorite tank chemical—so the bottom of the tank has a skim coat of water and chemical covering it. This locks in residual tank odors, and toilet waste lands in the water/chemical solution from the very first flush instead of hitting and adhering to the bare, dry plastic tank.

Use these additional resources to repair or replace various RV components: 

• Find the Best RV Toilet Replacement
• Maintain RV Holding Tanks Properly
• How To Clean RV Holding Tank Sensors

What RV toilet issues are you trying to fix? Let us know in the comments below!