What Size RV Holding Tank Do I Need? (Read This First)

If you are a beginner RVer or are someone who does not frequently travel in your motorhome, it can be challenging to determine what size RV holding tank you need.

Holding tanks are crucial to store your clean and dirty water.

Likely, you did not know that there are different size holding tanks, and depending on the size and class of the motorhome, you could have a smaller or larger set of holding tanks.

Fortunately, we’re going to have a closer look into the different size holding tanks according to the RV classes, and we will provide you with the information you need to help you determine what size holding tank you need:

Here’s The Answer To What Size RV Holding Tank You Need:

The size of the holding tank that you need will depend on your water consumption.

If you’re a solo traveler, you can use holding tanks with a 50-gallon water capacity or less.

However, if you’re traveling in a motorhome with a group of four or more, you will need holding tanks with a high water capacity of 80-gallons or more.

The Different Types Of Holding Tanks

Before we can look at the different RV holding tank sizes equipped in the different motorhome classes, it’s important first to understand what the various holding tanks are in your RV.

Below we have explained the three different types of holding tanks that you will find in your motorhome.

Freshwater Holding Tank

The freshwater holding tank is the tank that holds your freshwater or drinking water.

It is also the water that you will use to wash your dishes and that you will use to bathe with. The more people you are accommodating in your RV, the larger your freshwater holding tank needs to be.

Grey Water Holding Tank

Your grey water tank is where all your wastewater from your shower, bathroom sinks, and kitchen sink goes.

This water travels through your motorhomes plumbing system and is separated into the grey water tank. Often the grey water tank will also contain food particles and soap residue.

If you are only a solo traveler or are traveling with one other person, you don’t need a greywater holding tank that is overly large, especially if you will have frequent access to dump stations.

Blackwater Holding Tank

The holding tank that most motorhome enthusiasts hate to learn about is the blackwater holding tank.

This holding tank is where the wastewater from your toilet is stored. Special precautions need to be taken when you empty your black water holding tanks.

You’ll need a bigger blackwater holding tan when you have more people in your motorhome.

How Big Are The Pre-Installed Holding Tanks On Each RV Class?

How big a pre-installed holding tank in an RV is will depend on how many people it can accommodate.

If you have a large RV that can sleep six people or more, you will likely find that it has bigger holding tanks than motorhomes that sleep less than six people. Below we have given the average size you can expect the three holding tanks to be in each motorhome class.

Class A RVs

Class A RVs are undoubtedly the largest type of motorhome you can own, and although they usually have the largest holding tanks, this isn’t always the case.

In A Class A RV, you can expect to have a freshwater holding tank of between 72 and 100 gallons, a grey water holding tank of between 40 and 65 gallons, and a black water holding tank of between 31 and 51 gallons.

Class B RVs

Class B motorhomes are the smallest class of RVs, so they have the smallest size holding tanks.

A Class B RV has a freshwater holding tank capacity of between 16 to 40 gallons, a grey water holding tank capacity of between 8 and 35 gallons, and a black water holding tank capacity of between 10 and 26 gallons.

Class C RVs

Class C RVs have various sizes, with some being much larger than others depending on their manufacturer.

However, on average, in a Class C motorhome, you will find a freshwater holding tank capacity of between 35 and 60 gallons, a greywater holding tank capacity of between 31 and 91 gallons, and a blackwater holding tank capacity of between 27 and 63 gallons.

Travel Trailers

Travel trailers have various sizes and are becoming larger and larger.

However, you can expect a freshwater tank capacity of between 35 and 60 gallons, a grey water tank capacity of between 40 and 65 gallons, and a black water tank capacity of between 28 and 42 gallons.

Fifth Wheels

The fifth wheel RVs can be incredibly large and can have large holding tanks.

Most fifth wheels nowadays can compete with Class A motorhomes in terms of size. On average, a fifth-wheel RV can have a freshwater holding tank capacity of 50 to 92 gallons, a greywater holding tank capacity of up to 93 gallons, and a blackwater holding tank capacity of between 39 to 88 gallons.

Do People Generally Upgrade The Holding Tanks?

Many motorhome enthusiasts choose to upgrade their holding tanks when they plan on camping off-grid or at campsites with no water, electricity, or sewerage hookups.

However, it is not a simple process as many design features need to be considered, and a professional usually needs to be consulted.

Often a motorhome won’t be able to fit a larger holding tank than what was factory installed. Fortunately, if this is the case, there is a solution. You can upgrade your motorhome holding tanks by taking portable water tanks into your RV for your freshwater tank.

Unfortunately, you cant do the same for your greywater tank or blackwater tank as those are for wastewater.

How Much Water Do You Need Per Day On The Road?

How much water you will use each day when camping in your motorhome will depend on how many people are in your Rv and the types of daily activities you conduct.

For example, you will need more water if you take many showers or wash dishes or cook often.

On average, you need about one gallon of water per day for fresh drinking water per person. It would be best if you had another gallon of freshwater for cooking, cleaning, and brushing your teeth. Then depending on how often you shower and how long you shower, you might need up to 5 gallons of water per person.

To put it into perspective, a couple can use more than 2,000 gallons of water per month in an average residential home.

However, a couple living in their RV can use 100 gallons of freshwater in nine to 10 days if they are wise about the amount of water they use for various chores and activities.

Is It Common For RVers To Run Out Of Water?

It is relatively common for RVers to run out of freshwater when camping, especially if they have no experience camping off-grid or at campgrounds with no water hookups.

Many RVers don’t realize how much water they use for bathing and washing dishes daily. They also don’t consider that they need fresh water to brush their teeth and cook meals.

Moreover, some people forget that the more people they have, the more water they need for chores.

Can You Always Dump Your Water On RV Campgrounds?

Unfortunately, not all campgrounds have dump stations.

Many basic campgrounds only offer a parking space for your motorhome and no water, electricity, or sewerage connections. Fortunately, you needn’t worry as there are ways you can dump your blackwater and grey water tanks if you are at a campground that does not have a dump station.

You will have primarily three options. You can choose to search for a dump station near the campground you are staying at, or you can search for a campground with a dump station and ask to use their facilities even though you won’t be staying at their campground.

Both of these dumping options will likely cost you a fee. The third option you have available is to dump your grey or black water tanks at your home.

However, there are rules around this dumping practice. For example, you will often need to get permission, and you will need to ensure that you pump your water directly into the main sewer line or septic tank and not into a stormwater drain.

Alternatively, you can dump your grey or blackwater down your home’s toilet system, but this is often messy.


A Beginners Guide To RV Holding Tanks

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