It’s happened at home, and it can happen in your RV – the sink or shower gets clogged with debris and doesn’t drain properly, or at all. It’s never fun, and it’s always messy. However, clogs in RV gray water plumbing systems, while annoying, can be easily fixed if you follow our simple steps to get rid of the existing clog, and prevent clogs from happening in the future.

If you’re experiencing clogs in your RV black water plumbing system, please review our guides: 3 Common Types of RV Toilet Clogs You Should Know About and How to Prevent Clogs in Your RV Black Water Holding Tank.

Key Points About Unclogging RV Gray Water Plumbing Systems

• There are multiple places where RV gray water clogs may occur: p-traps, waterless traps, and beyond the traps in RV fixtures (sink, shower, dishwasher, reverse osmosis system, gray water holding tank, plumbing between holding tank and discharge valve).
• Clearing RV gray water plumbing clogs is relatively simple and easy.
• Simple, preventative measures can significantly reduce the chances that you’ll have to deal with RV gray water clogs.
• Keeping RV gray water holding tanks clog-free long term requires regular deep cleaning. The process only requires grease-eating dish soap like Dawn Ultra and following the steps outlined by The Unique Method.

Types of RV Gray Water Clogs

RV gray water plumbing system clogs can occur in any freshwater RV drain other than the toilet (black water systems). All of the sinks and showers in RVs have plumbing “traps” very close to the drain that are put in place to prevent sewer odors from coming up through the drain and into the RV.

These traps are often the area where clogs form in RV gray water plumbing systems.

We’ll dive into each of the most common RV gray water clogs to help you determine what kind of clog you may be dealing with.

RV Gray Water Clog Type: P-Traps

P-traps are common in households and RVs alike. These simple pieces of plumbing consist of a curved PVC pipe that is named after its shape, which looks like a “p” that’s been tipped on its side, with the bend in the pipe “trapping” several ounces of water.

P-traps are installed to create a liquid barrier that blocks odors coming from the gray water holding tank and sewer port, and prevents them from coming up through the RV drains.

Because p-traps create an intentional bend in the pipe, it makes them ideal for blocking odors, catching debris dropped down the sink or shower drain, and you guessed it, can also make them the ideal place for clogs to form.

RV Gray Water Clog Type: Waterless Traps

Waterless traps, also known as HepVo traps, have been used for years – primarily in households and RVs where space under the sink or shower is limited. Because of their low profile, this style of trap is being used more frequently in RVs.

Rather than using water as a barrier, these traps use a one-way diaphragm that acts as a self-sealing waste valve, preventing gray water tank and sewer odors from coming up through the RV drains. Waterless traps are composed of a rubber tube situated in the middle of a PVC pipe that is held open on one end, and soft enough on the other end to “close” when there is no water present in the rubber.

Waterless traps create a significant bottleneck in the pipe, and when “closed”, the end of the trap can easily get clogged with hair and other debris that may go down the sink and shower drains.

RV Gray Water Clog Type: Clogs Beyond Traps in RV Fixtures

While clogs can easily develop in p-traps and waterless traps installed by the sinks and showers, they can also occur beyond the traps, or in drains coming from other RV fixtures.

Properly designed RV gray water plumbing systems include a natural slope that leads piping down toward the RV gray water holding tank. This allows gravity to ensure that anything in the pipe makes its way to the holding tank, as intended.

The initial design works well when an RV is parked on a completely flat surface, but when you are out on the road, you are unlikely to find perfect grading at every campground you encounter. If the natural slope of the pipes downward is interrupted by unlevel conditions, then clogs are able to form when liquid and debris aren’t able to move down to the holding tank properly.

Unlevel conditions can cause clogs to form between the plumbing and the gray water holding tank itself, and even in the pipe beyond the gray water holding tank that goes to the discharge port.

Steps to Unclog RV Gray Water Plumbing Systems

Now that we’ve learned about the types of RV gray water plumbing clogs, let’s get into how to clear them. If you follow the simple steps below, you’ll be able to clear RV gray water clogs quickly and efficiently, and be able to enjoy fully functioning drains in no time.

How to Clear RV Gray Water Clogs:

1. Confirm which sink, shower, or other RV fixture is draining slowly.
   • If the clog isn’t affecting the RV’s fixtures, and is in the pipe beyond the gray water holding tank between the tank and the discharge port, proceed to step 8.
2. Determine the type of trap you have. Open the panel or cabinet that exposes the plumbing to indicate which type of trap you’ll be working on.
   • If you have a P-Trap, proceed to step 3.
   • If you have a Waterless Trap, proceed to step 5.
     Note: if you are dealing with a waterless trap, you should not use a toilet snake while the trap is still installed.
3. Remove drain plug assembly, or drain cover.
   • Important note: Only disassemble any system in your RV if you are confident that you can put it back
4. Slide a short, plastic snake down the pipe.
   • We recommend short, plastic toilet snakes to try and pull free any stubborn hair or debris that may be causing the clog.
   • Plastic snakes are easier to handle, and are less likely to cause damage compared to full-sized, metal plumbing snakes.
   • It may take several passes to clear the clog before you’re able to rinse water down the drain normally.
5. Remove the waterless trap. Unthread the plastic fittings on either side of the trap to remove, check for clogs, and rinse thoroughly.
   • Friendly reminder: Only disassemble any system in your RV if you are confident that you can put it back together again.
   • If the clog was not in the waterless trap, proceed to step 6.
   • If the clog was in the waterless trap, proceed to step 7.
6. Run a toilet snake down the drain beyond where the waterless trap was installed.
   • It can take several attempts to clear the clog before you’re able to rinse water down the drain normally
7. If the clog has been cleared, reassemble your trap, and flush water through the system.
   • Flushing water through the system can help clear any residual debris out of the pipe.
   • If the debris causing the clog moved into the gray water tank, water can help break it up while it sits in the tank prior to dumping.
8. If the clog has not been cleared, there may be a clog between the RV gray water holding tank and the discharge port.
   • Drain your RV gray water tank as much as possible.
9. Run a full-sized, metal plumbing snake up from the discharge port towards the RV gray water tank.
   • Clogs in this part of the RV gray water system may be holding back significant amounts of water, so be mindful of your positioning as you work.
   • This section of the RV gray water plumbing system may include long runs of pipe, which is why the full-sized metal snake may be required to free the clog.
10. Once you have cleared all clogs, thoroughly rinse your RV gray water plumbing system.
    • Rinsing your RV gray water plumbing system can remove lingering residue from the clog, and can prevent secondary clogs from occurring as the debris moves through the tank and out through the discharge port.

If you’ve followed these steps, you should now be enjoying a smooth-draining, clog-free gray water system in your RV.

However, if you’ve followed these instructions and you’re still having trouble, don’t worry, our dedicated Customer Service Team is ready to help you diagnose the problem, and get your RV gray water system back on track.

How to Prevent Clogs in RV Gray Water Plumbing Systems

Now that we’ve covered how to fix clogs in your RV gray water plumbing system, let’s cover how you can avoid them from happening in the future. We’ve put together some of the best practices you can put in place to prevent clogs long term.

1. Install Screens or Strainers in RV Drains

One of the best ways to prevent clogs in RV gray water plumbing systems is to prevent hair and debris from going down the sink and shower drains. By installing screens or strainers, you can catch these clog-causing items ahead of time. We like these for sink drains, and these for shower and tub drains. Clearing the screens or strainers is very easy, as you can simply throw anything caught in them into the trash, rinse them, and then put them back. This first level of defense can prevent the majority of RV gray water clogs.

2. Avoid Dumping Grease Down RV Sink Drains

Another way to prevent clogs in RV gray water plumbing systems is to refrain from dumping grease down the drains. When grease is poured down a sink drain, it eventually cools, solidifies, and sticks to the inner walls of the pipes and gray water holding tank, and can eventually build up so much that it creates a clog.

While some grease may inevitably make its way down the drain, scraping plates before washing them in the sink, or washing heavily greased dishes at community wash sites, can reduce the amount of grease dramatically.

3. Level Your RV Completely

The third way to help prevent clogs in RV gray water plumbing systems is to level your RV completely whenever you arrive at a campground.

Aside from the general benefits of RV leveling – properly functioning appliances, accurate tank readings, living space stability – ensuring your RV is completely level will allow water and debris in the gray water plumbing system to flow naturally down the slope of the piping and into the gray water holding tank effectively.

If the camper is not level and the pipes no longer benefit from a downward slope, debris may get stuck in the pipes and create clogs.

4. Regularly Deep-Clean RV Gray Water Holding Tanks

The final way to prevent clogs in RV gray water plumbing systems is to follow a regular deep-cleaning schedule. While following all of the other preventative measures can help prevent RV gray water clogs, inevitably, some grease, residue, and hair will still build up over time.

Grease and residue buildup in RV gray water holding tanks can not only cause clogs, but can also be a source of unpleasant odors, and can cause misreading sensors. Thankfully, deep cleaning RV gray water holding tanks is very easy, and only requires water, grease-eating dish soap (Dawn Ultra), and time. The process can even happen overnight while you sleep.

Deep cleaning your RV gray water holding tank ensures that your gray water systems can function properly trip after trip. Hookup campers should deep clean twice a year, while dry campers should deep clean on the last night of every camping trip.

For step-by-step, deep-cleaning instructions, please review our guide: How to Deep Clean RV Gray Water Holding Tanks

RV Gray Water Clogs & The Unique Method

If your goal is to think less about your RV’s gray water plumbing system, and more about the next campground to visit, then implementing The Unique Method will help you make it happen.

Tried, tested, and proven to work, Unique Camping + Marine created this method to help you solve 99% of your RV wastewater problems before they even occur. The guidance is simple: follow the right steps, and use the right products.

When deep cleaning RV gray water holding tanks, the most important product you need is a grease-eating dish soap like Dawn Ultra. After 30 years of solving wastewater problems professionally, Dawn has been found to be the most effective for removing RV gray water tank grease without leaving behind any additional residue.

Important Note About Chemical Drain Cleaners: Currently, there are no chemical drain cleaners that we recommend using in RV gray water plumbing systems. When chemically-derived drain cleaners are poured down RV drains, they end up in the gray water holding tank. RV gray water holding tanks have plumbing connections and sensors which are secured with rubber gaskets and bushings.

Chemical drain cleaners can easily damage these components, causing more issues than the clog you’re already trying to clear. So, rather than using a chemical drain cleaner, we recommend following The Unique Method for the safest and most effective results.

Review: Unclogging RV Gray Water Plumbing Systems

Clogs in RV gray water plumbing systems seem like an inevitable part of RVing – fortunately, they don’t have to be. You can clear RV gray water clogs quickly, and prevent them from occurring, by following the easy-to-follow steps outlined by The Unique Method, and using the right products. It really is that simple. By developing good habits now, you can enjoy clog-free camping when you trust Unique Camping + Marine to be your guide.