RV Toilet Not Holding Water – Easy Solutions

When you buy through links on our site, we may earn an affiliate commission, Read More.

Finding why your RV toilet not holding water could be tricky, particularly if you’ve never faced this before. However, in this article, I am about to nail the very reason and fixes to help you out in this respect. Not to mention, the toilet is a significant part of our RVs and a must-have especially when we go off to places for camping. 

However, things might go wrong at times and suddenly you may see the RV toilet stops holding water. The situation could be very unpleasant knowing that it will allow odors to make their way into your cabin. The reason you see no water when flushing RV toilets is due to the faulty blade seal. 

The rubber components may have been hardened, become perished, or simply damaged to the extent that the mechanism no longer works. And, the fix is as simple as replacing it with a new one. Scroll down and you’ll end up knowing more about this.

Basics Of RV Toilet

Basics Of RV Toilet

The more familiar you are with the toilet, the better you understand how to fix it when a problem arises. So, before I move onto the main discussion, let me first present a brief overview of the basic RV toilet parts and how they function. Let’s begin. 

1. Seal and Valve

If you notice, the seal and the valve are positioned at the center of your toilet bowl that holds a small amount of water all the time. This part of the toilet acts as a barrier to the disgusting smells redirected from the sewage tank to access the RV’s main compartment. So, when you start smelling bad, you can safely assume where things have gone wrong and repair accordingly.  

2. Water Module

In order to use any toilet, you must have access to water. And, the water module serves this purpose as it connects to the rig’s water supply. Fortunately, RV toilet manufacturers understand the significance of this mechanism and offer replacement parts for their particular models.

3. Foot Pedal

This is one area where RV toilets differ from the residential models. Rather than a traditional hand flush, most RVs have a foot pedal to perform the task. However, note that depending on various models the functionalities of a foot pedal will vary.   

To perform a flush some toilets will need you to step on the pedal first and then lift back up to fill the bowl with water again. In contrast, others may fill the bowl halfway and then flush when stepping down completely.

Camco 5.3-Gallon Portable Travel Toilet - Features Detachable Holding Tank w/Sealing Slide Valve &...
  • Portable Travel Toilet: Provides a convenient bathroom spot while on-the-go; Ideal for camping, RVing, boating, road trips and other recreational activities; Detachable Holding Tank: 5.3-gallon holding tank is detachable for easy emptying
  • Stops Leaks and Odors: The locking lid helps prevents spills and the sealing slide valve locks in odors/protects against leakage; Side latches secure the tank to the toilet
  • Easy to Flush: An easy-to-use bellow-type flush and pull slide valve provide simple flushing

Fixing A RV Toilet That Won’t Hold Water

Fix A Leaking RV Toilet Seal

Taking on RV toilet repair is not a big deal for an average DIY person to handle. And, when it’s time to replace the RV toilet seal it’s even simpler. So, consider doing this yourself if you neverminded the toilet work and like to save some bucks. Having said that, you shouldn’t take the risk when your DIY skill is questionable. After all, you don’t want a poorly repaired toilet today only to face all those problems later. 

You can always call a plumber for help and avoid getting into more serious trouble. Therefore, carefully evaluate the cost-benefit trade-off according to your specific condition. However, if you are confident enough, be sure to have the right replacement kit available upfront.

Aqua-Magic V RV Toilet Pedal Flush / High Profile / White - Thetford 31671
  • Fit Type: Universal Fit
  • Included Components: Aqua-Magic V High Profile Flange Seal 2 X Bolts 2 X Nuts 2 X Bolts Covers

How to Choose RV Toilet Replacement Kit

There is no surprise that RVers often discuss Thetford RV toilet leaking around online since it has been the best-selling RV toilet to date. Although there are various models from Thetford, your toilet doesn’t necessarily fall in that group. What is important is to buy the replacement kit designed for your particular model when you see the RV toilet is not holding water in the bowl. Ideally, you should have the RV owner’s manual available, and in this case, finding your very model gets a lot easier. 

The model number should also be sealed somewhere on your toilet, probably at the bottom half. To buy your desired blade seal find any hardware store that sells RV parts. Alternatively, you can find it on amazon. The price varies between $15 to $20, little compared to some RVers who become too concerned as RV toilet water is not flowing, assuming that the repair is a costly one.

Mission Automotive Flush Ball Seal fits Dometic 300/310/320 RV Toilets - Comparable to Part...
  • Perfect For 300 / 310 / 320 Models -- Our flush ball seals / flush ball gaskets are compatible with Dometic (TM) 300, 310 and 320 RV, motorhome and trailer toilets. These flush ball seals replace Dometic (TM) flush ball seal kits # 385311658
  • High-Quality Material, Made To Last -- Our valve seals are made from a high-quality, application-specific rubber blend for optimal performance and a long-lasting lifespan
  • DIY Install Saves Money! Don't go out an buy a new toilet or pay someone an arm-and-a-leg to change the seal - follow our instructions below and you'll be back up-and-running in no time

Tools You’ll Need to Fix A Leaking RV Toilet Seal

CRAFTSMAN Adjustable Wrench Set, 3-Piece (CMMT12001)
CRAFTSMAN Adjustable Wrench Set, 3-Piece (CMMT12001)
CORROSION RESISTANCE: The adjustable wrench set has full polish chrome finish; QUICK SIZE IDENTIFICATION: Adjustable wrench comes with large markings
DEWALT Socket Set, 1/4-Inch & 3/8-Inch Drive, SAE/Metric, 34-Piece (DWMT73804)
DEWALT Socket Set, 1/4-Inch & 3/8-Inch Drive, SAE/Metric, 34-Piece (DWMT73804)
Mechanic socket set comes in locking, stackable case with removable inner tray; Metric socket set 3/8-inch drive exceeds ANSI specifications
G & F Products 12 Pairs X-Large Rubber Latex Double Coated Work Gloves for Construction, gardening...
G & F Products 12 Pairs X-Large Rubber Latex Double Coated Work Gloves for Construction, gardening...
Double dipped latex coating provide extra heavy duty; Cotton blend technology, rubber coated with Blue latex

Step 1:

Disconnecting the water supply is the first step in regards to any plumbing issues that you’ll handle. As previously mentioned your toilet has a water valve too, that is connected behind. Turn it off first. Now flush the toilet bowl and empty the drain line. This will ensure that the residual water pressure is released, and nothing is coming back in. Alternatively, you can shut off the main pump in case your RV doesn’t have a water valve in place. 

Step 2:

Generally, your toilet will be secured with the floor having two bolts on each side. They are often covered with a cap that is easily removed. Once you detach them, grab your wrench and loosen the nuts out. 

Step 3:

Now before you can lift the whole unit (toilet), make sure the water supply hose is disconnected from the inlet valve. Put your toilet in a safe place keeping a fair distance from your workstation. 

Step 4:

The drain hole will be exposed at this point. When it may not be necessary, I would recommend putting a plastic bag across there since stinky odors coming from the sewage tank could be quite uncomfortable. 

Step 5:

Now it’s time to disassemble the bowl. You might need a 3/8-inch socket wrench to remove the fastening screw hidden behind. Ensure all the bolts are removed and rotate the bowl counter-clockwise to release it from the locking tab. 

Step 6:

The old blade seal will be exposed at the moment. Now, remember that the area around the seal is relatively delicate. Therefore, when it feels too sticky to remove, go slowly so that any damage can be avoided. 

Step 7:

As soon as the old seal is removed, make sure the area is clean before you place the new one. Your latest seal may come with a specific instruction, in which case following it would be necessary. Carefully center the seal above the toilet drain. You might also want to scrub clean the surroundings wherever accessible. 

Step 8: 

Lastly, carefully reassemble the bowl to the toilet. And the toilet at the base. Tighten all the bolts properly in place. Finish by turning the water on and with a test flush to verify.

Other Reasons For RV Toilet Not Holding Water

rv toilet won't hold water

1. Water Valve Is Broken

If you wonder why won’t my RV toilet bowl hold water, know that a worn or broken water valve might as well be responsible for this. There comes a moment in your toilet when you see the water is seeping into the bowl continually when you flush it. 

This RV toilet problem is usually seen during winter when the water valve is frozen and then thawed back later. Luckily for you, the fix is a simple one to tackle when buying a new one is inexpensive at the same time. To reduce the chances, try to find and park your camper at convenient places with less vulnerable winter conditions.

Byenins New Durable Plastic Water Valve Kit 385311641 for 300 310 320 series - for Sealand marine...
  • 385311641 valve replacement part.
  • Replace the leakage valve,simple installation.
  • When connecting the water pipe, do not over tight it,avoid thread damage.

2. Broken/Worn Out Flange

Replacing a worn flange is a regular occurrence in RV toilet repair, often done to stop toilet base leakage. The leak usually happens once a flush cycle is finished. In the worst case, water even leaks without a flush. Be sure to consult a professional before pulling off the toilet if you aren’t competent in this task.

3. Obsolete Parts

Plastics and rubbers are found nearly everywhere on an RV toilet and hence there’s less risk of wear in general. However, some parts of it will be either broken or decayed at some point. But the good news is, all the individual parts can be purchased separately on Amazon.

Tips for Maintaining an RV Toilet

Undoubtedly, the RV toilet is part of our campers where we all like to be free of issues. That said, it won’t be practical if I say, you can prevent all those from happening. However, if the toilet is properly maintained many of them could easily be avoided. Here are some crucial tips pertaining to RV toilet maintenance:

1. Blade Seal

As stated earlier, the blade seal is responsible for seeing some water always held inside the bowl. However, when it is hardened a leak can emerge allowing these waters to seep into the holding tank. A quick fix would be to lubricate the seal by applying waterproof sealant on its surface. However, when the seal is badly decayed or damaged consider replacing it with a new one.

DANCO Waterproof Silicone Faucet Grease | Silicone Sealant | Plumbers valve Grease for O-rings | 0.5...
  • PLUMBERS FAUCET AND VALVE GREASE Ideal for lubricating faucet stems valves and cartridges when repairing a leaky faucet
  • LUBRICANT GREASE Contains high raw silicone content making it better for long term lubricant hold & helps hard-turning faucets work smoothly
  • NSF 61 APPROVED designed for use as a waterproof lubricant on faucets valve stems cartridges and is safe for nitrite/rubber O-rings

2. Tank Treatment

Nobody likes their RV septic system to be clogged and face serious trouble. That’s why routine tank treatments become obligatory to allow the system to process waste. You can make it hassle-free by keeping handy deodorizers while onboard and dropping a few in the drain line periodically. They help break down waste more effectively and thereby clogging will no longer be an issue. 

Walex Porta-Pak RV Marine Black Holding Tank Deodorizer Drop-Ins, Camper, Boat, Camping Cassette...
  • WASTE BREAKDOWN - Porta-Pak RV Marine Holding Tank Deodorizer breaks down waste and stubborn RV toilet paper, keeping your holding tank sensors working effectively. No more clogs or backups.
  • HOLDING TANK DEODORIZER - Porta-Pak marine and RV holding tank deodorizer tackles unpleasant smells. Say goodbye to embarrassing odors with your boat, camping toilet, and RV toilet tabs.
  • VERSATILE FOR ALL TANKS - Our marine and RV tank deodorizer for black tank cleans tanks from 2.5 gallons - 40 gallons. Ideal for RVing, boating, boondocking, and portable camping cassette toilets.

3. The Toilet Bowl

Nowadays, it’s common for modern RV toilets to be equipped with an attached sprayer for efficient bowl cleaning. However, if you’re using an older version and the flush isn’t powerful consider keeping a small plastic cup alongside the toilet. Use it to pour water around the bowl as you flush. Alternatively, a plastic water gun can be used as well.

4. RV Safe Toilet Paper

The condition of the RV septic line is well influenced by your toilet paper. And, if you’re not keeping RV friendly toilet paper in your bathroom, the septic system is bound to get clogged. Therefore, keep an eye on this and make sure you are investing in good biodegradable papers that flush down and dissolve easily.

Freedom Living RV Toilet Paper (2-Ply, 8 Rolls, 500 sheets each) - Biodegradable Septic Tank Safe...
  • MORE FUN LEISURE TIME: Enjoy spending more quality time in the great outdoors or with your family instead of unblocking smelly toilets and dealing with filthy septic tanks
  • DISSOLVES AS SOON AS ITS DONE ITS JOB: Septic Tank and Chemical Toilet Safe Toilet Tissue Paper dissolves completely in mere minutes yet is gentle and durable enough for the task at hand and won't rip or tear unexpectedly
  • 100% BIODEGRADABLE - Perfect for RVs, tiny houses, off-grid living, boats, yachts, marine, camping, hiking, eco retreats, composting toilets and other septic tank users

5. Holding Tank Sensor

Sometimes the holding tank might give you a false reading especially if residues get stuck on the sensors. These sensors are pretty sensitive and the tank reads full even after it is being emptied. Ice treatment could be useful here. Simply drop a few ice cubes into your RV toilet. And hopefully, they will melt and clear the sensors off any leftovers to reset.

Valterra T21301VP Horst Miracle Probe - Black Water Tanks, Pack of 4
  • Easy to install, fits the 3/8″ diameter holes of existing probes.Fit Type: Universal Fit
  • Easy to install, fits the 3/8″ diameter holes of existing probes
  • Compatibility with existing wiring and monitors

Upgrading Your RV Toilet

Unlike the trend, nowadays modern campers and high-end RVs are providing toilets with additional features. If it doesn’t sound exciting to you, for some people upgrading their toilet becomes a necessity. Like it was the case for me when I wasn’t too happy with a plastic Thetford originally installed on our camper. Using this low-profile, rounded toilet wasn’t comfortable to use.  

Lately, I switched to the Dometic 320 Series that mimics the exact height and shape of a residential toilet. Yes, it cost a little extra, yet it was money well spent after all. And if you have been planning to upgrade, manufacturers like Thetford and Dometic are offering an increasing number of options you can choose from. 

Moreover, things become simpler knowing that you can add certain accessories to the existing toilet and avoid changing the whole unit. For instance, you can turn your toilet into a bidet, and bring a spa touch, just by adding a bidet seat attachment. It is easy to install and not at all expensive either.

Dometic ReVolution 321 Series RV Toilet - Bone
Dometic ReVolution 321 Series RV Toilet - Bone
Deep, 100% Vitreous Ceramic Bowl | Full-Size Residential Style Wood Seat; Dimensions – 22” L x 14.75” W x 15.5” H | Weight – 36.99 lbs.

Final Verdict

RV toilet not holding water is undoubtedly very annoying especially when it ruins your long waited camping experience. In the end, I believe reading this article has helped you understand what goes into an RV toilet, why it fails to hold water, and what to do about it as a whole.

Eric Weldon
Eric Weldon
Hey Everyone! Thank you so much for stopping by and checking out our blog! We are very happy and excited to have started this journey of blogging about adventuring in Our Trailer! Please stay awhile, comment or share anything you like or let us know what you don't 🙂