How Much Water Does a Motorhome Water Tank Hold?

Motorhome water tanks are pretty straight forward as they are the place that holds the water that is used for showers, taps and flushing the toilet. Something you might want to know is how much water a motohome water tank can hold, how to care for it and if you can use it as drinking water.

The typical motorhome water tank can differ considerably in size and can range from 31-48 gallons on average. At a consumption rate of 6 gallons per day, these water tank sizes will last from 5-8 days.

In this article we are going to talk about how much a motorhome water a tank can hold, what you need to know about the water in a motorhome tank and how to keep your water tank clean.

How Much Water Does a Motorhome Water Tank Hold?

This would overall depend on the size of the Motorhome. A large motorhome would have a larger water tank while a smaller motorhome will have a smaller water tank. The typical RV water tank can differ considerably in size and can range from 31-48 gallons on average.

At a consumption rate of 6 gallons per day, these water tank sizes will last from 5-8 days.

You are definitely going to have to shower at campgrounds as the days go by, you can take short showers with low flows of about 2 gallons per min then use about 4 gallons for toilet and hand washing.

One of the biggest conveniences that comes with motorhomes is their ability to produce both hot and cold water. This makes your journey and life very enjoyable on the road since water for all your need is provided.

Below is a table comparing different Motorhomes and their water capacity:

Motorhome Make and Model Freshwater tank capacity (gal)
Winnebago Micro Minnie31
Winnebago Minnie37
Keystone Bullet43
Jayco Jay Flight42-48
Dutchmen Aspen Trail52

Working Principle 

The motor home has two water tanks; one for greywater (water from the sink) and freshwater(clean water for your daily activities). These two tanks needs to be emptied and refilled overtime. You can find a dump station where you can dump and refill these tanks around your environment.

They are also free to use though you might need to pay for access to potable water.


The freshwater tank on your motorhome will need to be refilled before it’s used. Many motorhomes have a tub and hot water heater in them. You need to first turn on your taps or showers to turn on your water pump.

Your motorhome control panel can turn on the 12V house battery and pump water through this.

The Carado motorhome’s water pump is automatically triggered when the house battery is charged. Switch the pump off while it’s not in operation (e.g. at night) to prevent excessively draining the motorhome battery.

To obtain the right volume of water, you are going to have to refill the fresh water tank many times especially if everyone showers every day.

Also, make sure to clear the grey water tank. You can easily check your freshwater level on your motorhome control panel.

For Hot Water

When you are camping outdoors, your hot water is heated using a supply LPG/propane tank, or 240V mains power supply if you can get a power source at your campsite.

About 40 minutes before hot water is needed, you need to turn the heater on as 10-15 litres of water would be heated, which is normally adequate for a short shower or washing dishes.

For Drinking

The freshwater available in the UK from mains water sources is generally safe for consumption. Water sources in certain remote regions, however, can bear waterborne microbes that may cause disease.

Check for indicators that instruct you to boil water before drinking, this is very important information. Generally, you should boil your water before drinking. 

Some motorhomers tend to use distilled water directly from the site tap for drinking or filling a small container and focus on the fact that boiling water is used in cooking and tea making, which can destroy bacteria.

Apart from the recent uproar over the overuse of plastic bottles, when contemplating safe water standards for cooking food and brushing teeth, such use is not so practical.

But does the water from your motorhome tank still need to be deemed unsafe? What threats are there?

Generally, if kept for longer than 24 hours, water can not be used as its consistency would degrade. The chlorine put into the water by most drinking water providers to keep it clean would have dissipated within this time span and the water may be at risk of becoming a host of bacteria that can be detrimental to health.

Its not one of the best practices if your motorhome water system is left to hold stagnant water in the pipes between your trips, especially in warm weather. A biofilm can be formed on the internal surfaces of the pipes and tanks by a water delivery system which does not have a daily water turnover.

In addition to this, limescale can build up in the atmosphere using hard water, which can add to the bacteria multiplication area.

You can consider selling your old motorhome when at this stage, however items that are simple to use are readily available to descale and sterilize your system to keep you secure.

Grey Waters

Grey water contains wastewater flowing into the grey water tank from the sink, tub and hand basin. Do not pour anything into the drains other than water. The drain can be blocked by food scraps, beef fat and even coffee grounds.

As some water goes into the toilet, the grey water tank is generally bigger than the freshwater tank, so you may need to drain the grey water slightly before emptying the freshwater.

In general, doing both jobs at the same time at a dump station is better. Blackwater is different from grey water and both are connected to the toilet system.

Emptying Your Greywater Tank & Refilling Your Freshwater Tank

You can drain your greywater tank and refill with fresh water at any authorized dump station. You should be on the look out for the blue and white sign of a motorhome dump station with a downward arrow.

  1. Just park as next to the dump station as you can. There is a bag of two different hoses for freshwater and greywater in your motorhome’s service locker.
  2. Connect the provided grey water hose on the side of the motorhome to the tank outlet and bring the other end into the drain of the dump station. On the grey water tank, turning a handle enables the water to flow out.
  3. A freshwater tap is generally situated a few meters away from the drain for waste disposal. Always use the freshwater hose provided to empty the water tank. Do not use the hose provided at the dump station.
  4. Attach the tap to the freshwater hose and position the other end in the freshwater inlet for around 100mm. Turn to mild pressure on the tap.
  5. You will have to fill up the water tank till it reaches its full capacity. if the inlet from your freshwater tank is on the side instead of the front. Make sure the overflow chute is open during filling and avoid letting the water overflow into the service locker. The clear-sided tub would allow you keep an eye on the water level in the tub.

How Does My Water Level Affect My Motorhome Payload?

One litre of water weighs one kilogram, with 100 kg of payload carried out by a regular 100-litre fresh water tank filled to maximum capacity. That’s quite a high proportion in the payloads of most motorhomes, and you don’t need to drive around with an entirely full tank, it’s not recommended to do so.

Lugging around huge volumes of water means you can suffer from higher fuel consumption and driving stability can be decreased by sloshing around with a large tank. It’s advisable to verify what water you can lawfully carry with your usable payload.

The best way to get a trailer weighed is to drive it to a public weigh station (when fully filled, minus water, but including driver and passengers, the local council should be able to guide you in the right direction).

Compare your weight with the gross vehicle weight (GVW). Your spare payload is the difference between the load weight and gross vehicle weight (GVW), indicating the load is lower than the GVW.

How Long Should A Full Tank Of Water Last?

A fresh water tank can only last 2-3 days, and far less if there are more occupants than just a couple of two. Based on the average daily consumption of 6 gallons each and a volume of 30 gallons of water. This can be stretched out enormously if you save water.

Based on the capacity of the tank, number of people, and how it is used, the amount of time a full fresh water tank can last. The average water intake in a travel trailer is about 6 gallons of water per day. If you have a 25-gallon tank and a pair of two, you would have about two days of water left or four days if you have a 52-gallon tank.

Always Clean Your Tank

Only changing the water in the shower head every few days and flushing the tank regularly isn’t enough. There are a number of options for disinfecting water. Using them is a smart idea, but cleaning the biofilm from the tank itself is more effective.

The effect is that your dirty tank contaminates the water you put into it, and the water still isn’t necessarily clean.

To avoid leakage, the tank must be properly washed on a daily basis. Even though, there will also be some soil in the tank due to the original owner. Water tanks are typically kept sterile with the use of cleaning materials. That’s one of the most efficient ways of cleaning the tank, but bacteria can start to grow again after a couple of months.

In order to ensure the health of the tank and the water, you need to maintain good treatment. The notion that you don’t have to preserve your running gear during the season is all a fallacy. 

How To Sanitize Fresh Water In Your Motorhome

  1. Drain water heater
  2. Drain holding tank
  3. Drain low point drains
  4. Add half cup bleach to 30 gallons of water in the freshwater tank.
  5. Fill the water tank to capacity.
  6. Spray water heavily until you can smell bleach.
  7. Go for a drive to slosh around the water in the tank.
  8. Let it sit for twelve hours.
  9. Run water tanks.
  10. Refresh with adequate water.
  11. Run your faucet until you cannot smell bleach anymore.

Avoid Drinking Water From The Tank If You Can

Due to risks involved in drinking the water out of the tank, it is advisable not to drink the water. This will help prevent you from having a case of diarrhea. In fact, there’s a huge chance the water pipes are contaminated.

They’re difficult to search for when cleaning or debris, and are also the places which are likely to be dirtiest.

Moreover, the water in the tank is lukewarm and is less enjoyable to drink than clean, cold water pumped straight from the tank. Please note that the water quality in the United Kingdom is not as great as that in many other countries in the world.

That’s why we advise you to drink bottled water instead of tap water, because if you drink it cold it will still be cool and refreshing.

If you do not have easy access to water other than what might be in the tank, we ask that you thoroughly boil the water to destroy any bacteria. That is about how long it takes for the dangerous bacteria to be killed.

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