How To Prepare Your RV Holding Tanks For Storage

September 08, 2020

How to prepare your RV holding tanks for storage. Unique Camping + Marine

Key Points:

  • Properly storing your RV is important to keep your tanks and RV water system in working order
  • Winterize your camper at the end of the camping season to prevent pipe and tank damage
  • Always dump your black and gray tanks immediately after each trip
  • Always rinse/flush your black tanks after dumping (ideally for 20-30 min)
  • Store your black and tanks with clean water and a bacterial tank treatment when there is no danger of freezing

You might think storing your RV is as simple as dumping your tanks, maybe putting your camper in covered RV storage with wheel covers and that’s it, but there’s more to it than that. Improper storage of your RV holding tanks can lead to problems we all want to avoid. The first thing to realize about RV storage is that technically, if your RV is not in use, you are storing it. Storing your RV doesn’t have to mean for months or years. Even while it is sitting idle in your driveway or your RV storage lot until the following weekend, it’s still being stored and even that requires certain steps to ensure a fully functioning wastewater system. In this article, we will explain our recommendations for preparing your RV holding tanks for two types of storage:

  • Seasonal Storage - this is longer term storage, like storing it over the winter when it’s too cold to use or any extended period of time when you know you will not be using it.
  • Temporary Storage - this is shorter term storage, like a few days or weeks between weekend camping trips where it will be sitting idle for a little while but will be used again soon.

Seasonal RV Storage

Seasonal RV storage is when you are storing your RV over the winter and not intending to use it until temperatures warm up. Some seasonal campers like to adventure in the cold of winter, but others prefer to stick to the warm months. The climate in the location where you are storing your RV will determine how you should store it, and regardless of what type of climate you live in, deep cleaning both your black and gray tanks is a crucial step before putting your RV into seasonal storage or at least twice a year if you are taking trips year round.


Warm climates where freezing is not a concern
  1. Deep clean your black and gray tanks.
  2. Store your black tank with a full tank of water and Unique RV Digest-It; keep your gray tank empty.

The upside to using RV Digest-It is that you can leave it in the black tank for the entire seasonal storage period and it will not damage anything inside the tank. In fact, when you dump the water at the start of the camping season, you may find that your black tank is the cleanest it’s ever been.


Cold climates where freezing is expected
  1. Deep clean your black and gray tanks.
  2. Winterize your RV.

Deep clean your black tank for as long as possible before winterizing because the cleaner you can get your tanks before storage, the less likely you’ll run into problems the following season.


Temporary RV Storage

It’s always nice to take your weekend off work to enjoy the great outdoors in your RV, but come Sunday afternoon, you have to put it away and prepare for the work week. You might be planning on camping again the very next weekend, but you still need to properly store your RV in the short-term, even if that’s only a few days. This is what temporary storage looks like; that period of a few days or weeks between camping trips when your RV is not in use, sitting in your driveway or storage lot, but is not tucked away for the season.


Black Tank

Some people believe that storing an RV between camping trips is as easy as parking it in their driveway or RV parking storage, but think again. RV holding tanks are a little needier than a simple dump at the dump station and a rest in the driveway until the following weekend. There are some extra steps you need to take to avoid clogs and odors aside from just dumping after your last trip.

Dump your black tank. It seems like a no-brainer, but some people don’t immediately dump their black tanks after a trip. They think it’s ok to leave the wastewater in there during the week until they have a chance to dump it. This is definitely not recommended because sitting waste will always have the potential for developing clogs, odors, and misreading sensors. Just take the time right after your trip and dump the black tank so you don’t have percolating poop water in your RV.

Always rinse/flush your tanks after each trip. Whether you rinse the black tank(s) at the dump station or use the clean out at your home, you need to give it a good rinse before short-term storage. Gravity is what forces wastewater out of the tanks, meaning there will always be residual that clings to the walls and sensors. Without rinsing, this residue could dry out over the storage period, especially if it is warm outside which will cause moisture to evaporate quickly. Several things can develop if this habit is followed long-term:

  1. Misreading sensors
  2. Increased likelihood of odors
  3. Clogged and compacted tanks

We recommend rinsing your black tank for 20-30 minutes using a built-in tank rinser, flusher, or external wand. We know that conserving water is important, so even if you only rinse for a few minutes, it’s better than not doing it at all. 

Store your dumped and rinsed black tank with clean water and a treatment product. To further prevent the above-mentioned issues, we recommend that you store your RV with a black tank full of fresh water and a treatment of a high-quality bacteria and enzyme product like RV Digest-It. Even if you rinse your tank very thoroughly, you will likely still have some residual waste clinging to your tank walls. RV Digest-It will break down any residual waste during storage, keeping your tank odor-free and your sensors in proper working order.

There are always seasonal campers who will still go on trips into the late fall and could potentially be short-term storing their RVs into the time of year where freezing temperatures can arrive. Obviously, if you know temperatures will drop below freezing, do not store water and treatment in your black tank(s). At that point, either winterize your RV for seasonal storage or store your RV with empty tanks until your next weekend trip; if you do plan to camp into the colder season, be sure to take precautions to make sure your pipes don't freeze.

Note: If you are a bold camper who likes to push the limits of the camping season into the colder months, you may consider insulation options for your tanks so that they do not freeze while you are actually using them. Refer to our guide on How to Keep Your RV Holding Tanks from Freezing.


Gray Tank

The issues RVers encounter when temporarily storing their gray tank are not as serious as those they face when storing their black tank, but it’s still very important to properly prepare your RV’s gray tank for short-term storage.

Dump your gray/galley tanks. Again, seems like a no-brainer right? But there are people who see the gray tank as even less important to dump immediately because it does not contain human waste; only dish, shower/bath, and sink wastewater. However, the grease and oils in the gray/galley tanks can cause just as many problems as sitting wastewater from the black tank. Storing your RV with a full gray water tank can cause the grease and oils in it to float on the surface and coat tank walls and sensors. Hot temperatures outside can loosen grease, helping it spread and will lead to increased odors; colder temperatures will cause grease and oils to solidify, sometimes right on your sensors which can cause them to misread. Take the time to dump your gray/galley tank as soon as you’re done with your trip. We also recommend dumping the gray tank last, as the simple act of dumping it will rinse the discharge line of residual black water gunk after dumping the black tank(s) first.

Always deep clean your gray tanks with Dawn Ultra dish soap the last night of your trip. Gray/galley tanks can and should be deep cleaned at the end of every boondocking/dry camping trip with Dawn Ultra dish soap. It’s a very simple process that can be done overnight while you sleep and then dumped the following morning. For details on the deep cleaning process for gray tanks, refer to our guide on Deep Cleaning RV Wastewater Holding Tanks.

Do NOT put your camper into RV storage with a gray tank full of water. The best way to treat gray tanks for grease and oils is to deep clean it with Dawn Ultra dish soap, but there is no benefit to storing an RV with this cleaning concoction in the gray tank; it is much better to just dump, rinse and store empty until your next outing. Storing a gray tank with any water at all will lead to grease and oils being distributed around the tank which can cause more problems on sensors. Once your gray tank has been deep cleaned and you’re done camping for the season, you need to take appropriate steps to winterize your RV so that water lines do not get damaged.


Freshwater Tank

Freshwater tanks should be emptied after each trip. It’s always a better practice to fill your freshwater tank just before you leave for your trip instead of letting freshwater sit in the tank for long periods of time until you’re ready to use your RV again. Once you’re done with your camping season, empty the freshwater tank and completely winterize your RV to ensure no lines get damaged from freezing.




Adopt The Unique Method

You bought your RV so you could enjoy life and spend time with family and friends. The last thing you want to do is waste precious time and money on fixing wastewater holding tank problems. Keeping your tanks in peak operating condition doesn’t have to be hard, confusing, or expensive if you follow our proven process: The Unique Method.

The Unique Method is a comprehensive tank care plan that we developed after years of conversations with real customers facing real problems. The Unique Method provides you with simple, preventative steps to stop odors, clogs, and sensor problems before they start so you can spend less time worrying about your holding tanks and more time enjoying the freedom and adventure of RVing. Try it yourself and see why thousands of campers trust their RVs with The Unique Method every day.

If you need more help with anything covered in this guide or simply have a comment, we’re here to help you anytime!

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