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The Ultimate Guide to the Different RV Holding Tanks

Updated: Mar 16, 2022

The Ultimate Guide to the Different RV Holding Tanks

It shouldn’t come as a shock that your RV has a set of primary holding tanks. After all, they’re the reason you’re able to enjoy a hot shower or a fresh meal from pretty much any location you choose.

Plus, these tanks also provide that all-important plumbing that—frankly—your trips would look very different without. But how exactly do all of these tanks work, which part of your RV’s water system are they responsible for, and what does proper maintenance involve? Explore our ultimate guide to the different RV holding tanks to find out.

The Primary Types of Tanks

#1. Black Water Tank

We’ll start by explaining the functions of the less-pleasant but incredibly necessary black water tank. This particular tank is responsible for holding everything that gets flushed down the toilet. That means all solids, liquids, and toilet paper eventually end up in your black water tank. And hopefully, that’s all that ends up in there.

To be specific, RVs are formidable vehicles. But their plumbing isn’t necessarily as strong as a suburban home’s would be. So, avoid flushing other personal or feminine hygiene products down your toilet. It could cause blockage or damage to your black water tank, which is a problem you don’t want.

#2. Gray Water Tank

Next on the list is your gray water tank. This tank is essential to keeping things in your RV clean, fresh, and healthy. Gray water tanks are responsible for holding all the stuff that gets washed down your sink and shower drains. This, of course, includes things like food and other debris that might come out in the wash.

Thus, the stuff in your gray water tank is technically waste, but it’s not quite as gnarly as the stuff in your black tank. In any case, a well-functioning gray water tank is imperative to keeping things as hygienic and sanitary as possible. For these reasons, we had to include it in our ultimate guide to the different holding tanks in your RV.

#3. Fresh Water Tank

Lastly, there is the freshwater tank, which is, thankfully, exactly what it sounds like. It’s the tank in your RV that’s responsible for holding fresh, potable water. Essentially, this tank acts as a reserve so that when it’s time to take that hot shower or wash those fresh veggies, all you have to do is turn on the faucet.

Plus, the clean water in your tank comes in handy when it’s time to flush your toilets or use any other functional water feature in your RV. But it should still be cleaned and maintained regularly, like all of the other tanks in your system.

Determining Tank Capacity and Maintenance Requirements

The starting standard for an RV tank’s fill level is typically 15 to 40 gallons. However, your holding tanks’ capacity may differ slightly depending on how large your RV is. But regardless of your tanks’ specific sizes, the important thing is that you regularly track how full they are.

Fortunately, many RVs come with monitoring systems that alert you when things down below start to get dicey. That said, while these systems can be helpful, they’re not accurate all the time. Thus, being mindful of your trip’s length and how much water is in your tanks is vital. The more you camp, the easier it will be for you to glean how much water you’re using daily.

As a result, you’ll start to make some pretty good guesses about when it might be time to check, refill, or empty your tanks. If this is a point of great concern for you, we suggest going on a few shorter camping trips. Use these excursions as a litmus test to measure how much water you’re typically using. It’ll help you figure out what your tank maintenance schedule should look like on longer trips.

Filling Your Fresh Water Tanks

Many RV campgrounds and resorts have freshwater hookups onsite to connect you to city water through your rig’s inlet. So, the need to fill your freshwater tank won’t always be super urgent. However, suppose you’re camping in a particularly remote area or on a site without a freshwater hookup. If so, you must be diligent about looking after your tank.

There’s typically a separate inlet used for this type of filling method. It’s also wise to ensure that you’re using a specific sort of hose designed for potable water. If you want to up the ante, some RVers will also add a water filter to their hose before filling their freshwater tanks. In any case, make sure that your freshwater tank stays full of clean water, and you’ll be just fine.

Emptying Your Gray and Black Water Tanks

Now comes the part of RV tank maintenance that some tend to shy away from. We know emptying your black and gray wastewater tanks is not the most pleasant maintenance task. But improperly cleaning them or neglecting them altogether will yield some unsavory results. That’s why we implore you to read on to learn about the best and most painless methods for draining these tanks.

  • Black Tanks—Start with draining this one first. Then, release open the valve on your black tank and let it drain all the way. Wait until it’s full or once your trip has concluded so that there’s enough liquid to drain the solid waste quickly.

  • Gray Tanks—Once you drain your black tank entirely, open the valve on your gray tank and let it empty completely.

Why do it in this order? Well, the stuff in your black tank is going to be a bit grosser than the dirty shower and dishwater that drains from your gray tank. Basically, it’s better to get the worst of it over with first. Plus, this way allows the gray wastewater to flush out the sewer hose used when draining your tanks. Thus, the whole process is a lot more sanitary and manageable.

Maintaining Your Tanks Properly

Filling and emptying your tanks when necessary is crucial to keeping your holding tanks in excellent shape. But these tasks are not the only ones involved in-tank maintenance. There are a few things you should be doing in tandem with regular filling and draining to ensure the pristine condition of these all-important tanks.

First of all, your black tanks will require a deep sanitizing bath of special sewer chemicals from time to time. They help deodorize the tank and ensure that solid waste breaks down properly.

You’ll also want to flush your black tank system occasionally. Regarding your gray and freshwater tanks, they don’t need quite as much attention. However, it’s still beneficial to sanitize them periodically with bleach or a special sanitizer formula.

Of course, you must also be aware of any special needs your tanks might require as you travel. For instance, if you’re traveling through frigid temperatures, you might consider investing in some extra protection, such as RV holding tank heating pads. Having a bit of additional security will ensure that your tanks stay functional no matter what Mother Nature and the open road might surprise you with.

The Ultimate Guide to the Different RV Holding Tanks

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