Tap Not Working in Your Caravan or Motorhome? – 6 Potential Causes


Hi, I’m Chris, I run Horton Common along with my father Robert.

Being the owner of a small caravan site I get to see a variety of issues our guests may have with their caravan or motorhome. Often I’ll arrive on site as our guests are setting up their caravan or motorhome. After levelling up one of the first jobs many caravanners do is to get their Aqua roll and water pump ready. A couple of times while I’ve been in discussions with a guest their partner from inside the caravan has stated ‘the tap isn’t working?’. What usually follows is a perplexed look falling across their face as setting up the Aquaroll and pump was already completed? Well, the reality is there is a wide range of potential issues which may stop the tap and water system from operating in your caravan or motorhome. I’ll discuss several of these potential issues below:

Caravan Tap Not Working
The causes for a tap not working in a caravan or motorhome could be an issue with the tap itself, or it could be due to other issues: Image – Caravansplus.com

Some of these issues to stop the tap working are quickly resolved. Others can require a more hands-on approach and potentially some new replacement parts. With this post, I wanted to cover the most common issues which can stop your water tap from working. I’ll begin with the most likely and easy to fix issues and then progress to other potential problems and solutions. If you have the time to read this whole post, great. If not, you can use the Table of Contents below to jump to a particular issue with your tap you may be experiencing.

Introduction to Water Pumps on Caravans and Motorhomes

Sometimes the issue with a tap not working in a caravan or motorhome is due to the tap its self (microswitch) which I’ll discuss below. However, sometimes the issue is with the pump and water pipe. Therefore, I wanted to briefly cover the different types of water pumps used in caravans and motorhomes. There are two main types of water pumps. Submersibles, which actually go into your Aquaroll water container, and onboard diaphragm water pumps.

Submersible Water Pumps

The majority of caravans in the UK use a submersible water pump which drops down into the Aquaroll. The water pipe connection on the caravan not only connects up to the water pump but provides 12V power from the leisure battery. The two main brands of submersible water pumps used on caravans are Truma and Whale. These two brands of submersible water pump are very similar when it comes to flow rate and pressure. They can provide around 9-10 litres of water per minute at around 1 bar of pressure.

Truma Ultraflow Caravan Water Pump

Probably the most common submersible water pump found on caravans today is this Truma Ultraflow: Image – Amazon

Now, caravanners can experience a range of potential issues with submersible water pumps which I’ll discuss below. On some occasions, it may be due to pump failure. However more generally its because of the choice of materials used which can create issues for the user. For instance, the type of flexible pipe used between the caravan connection and the pump its self.

On-Board Diaphragm Water Pumps

You do find onboard water pumps on some caravans, however generally its motorhomes which tend to be fitted with onboard diaphragm water pumps. How a diaphragm water pump works is the motor lifts a piston up and down which is attached to a rubber diaphragm. Through lifting the diaphragm up and down suction is created along with positive pressure on the outlet. Through this method the water pump does not need to be lowered into the Aquaroll, its is permanently located inside the caravan or motorhome. A water pipe simply connects from one side on the pump into the Aquaroll. They are normally used on motorhomes as they can be linked up to large onboard water storage tanks.

Whale On-board Water Pump

This Whale ‘Watermaster’ onboard diaphragm water pump is a typical example, along with their Aquasmart onboard water pump: Image – Amazon

Caravan/Motorhome Water Pump Summary

Both submersible and onboard water pumps when they are working as intended do a good job. However, both can experience a range of issues which may lead to your tap not working. Below I’ll discuss problems which are applicable to both styles of the water pump. However, I’ll also discuss issues which are pump type-specific.

Tap Issues 1 – A Kinked or Bent Water Pump Pipe

Probably the most common issue I’ve come across with our guests and why the tap in their caravan or motorhome may not be working is a kinked pipe. As the pump and pipe are placed into the Aquaroll or alternative water container, the pipe can become kinked and bent. The reason this can often happen is because of the height of the water pump inlet on the caravan.

Most caravanners want to stand their Aquaroll up on its base for stability, and use the top screw cap for the water pump. However, some caravans (generally older vans) have a pump inlet port fairly low down. Hence the pipe exits the caravan and has to loop up and then down to get into the Aquaroll. This then creates a kink in the pipe, hence the pump cannot pull water through the pipe. I’m sure you have experienced this issue many times with a hosepipe in your garden at home.

To fix this issue, you obviously need to remove the kink in the water pump pipe. However, that can be easier said than done. In the video below Dan (Meet the Trugians) explains the issues he experienced with a kinked water pipe on his caravan:

As a result of a badly kinked water pump pipe, Dan chose to change from his Truma Ultraflow over to a Whale EP1642 submersible water pump.

Upgrading to a Whale Water Pump

So as you can see in the video above, Dan was experiencing real issues with his Truma Ultraflow submersible water pump. Due to the issue I described above with regards to the heigh of the water fitting, on Dan’s caravan this created a kink in the water pipe. I have seen this issue several times first hand. The type of ‘flexible’ pipe that Truma use on the Ultraflow can actually be pretty stiff. They can be prone to kinks and bends which stops water getting to the taps. Hence, if you are experiencing this issue with your Truma Ultraflow submersible water pump, you may also want to consider a change to the Whale alternative:

Whale EP1642 Submersible Water Pump

As Dan states in the video above and I also agree, the flexible pipe on the Whale pump is less likely to kink and bend than the Truma Ultraflow: Image – Amazon

However, what I do wonder is, does the flexible pipe used on the Whale submersible pump maintain the same degree of flexibility over time? All rubber and flexible plastic-based products over time become more brittle and stiff. However, another factor that can accelerate the ageing process is UV radiation from the sun. Obviously, these types of pipes can be exposed to a lot of US radiation, particularly in the summer months. Most of the Truma Ultraflow pipes which I’ve seen with kinks were actually pretty old. Therefore, I wouldn’t be surprised if over time the Whale submersible pumps also develop the same kink.

How to Address a Pipe Bend Issue with Onboard Pumps?

So changing from the Truma Ultraflow to the Whale submersible water pump is fine some caravans and motorhomes. But what if your tap is not working due to a bent pipe and you have an onboard water pump? In that scenario, you will have a coupling with a length of pipe and a filter on the end. However, the filter tends to be quite light and often doesn’t provide sufficient weight to keep the water pipe at the bottom of the water container. Well, this an issue Keith and Michele have experience in their caravan. I’ll let them explain how they resolved this issue:

You may want to source a ridge insert for your Aquaroll to avoid the issue with bends and the water pump running dry.

Tap Issue 2 – Microswitch Failure

Many caravans and motorhome have microswitches within each tap. When you lift the tap this tiny microswitch completes the connection, and the water pump is activated. However, over time this little tiny (and sometimes fragile) microswitch can fail. If you think this may be the cause for your tap not working within your caravan or motorhome, it may be worth watching the video below by John from Practical Caravan:

Tap microswitches can fail, so its a good idea when possible to have some spare to hand (along with a screwdriver).

If you believe a faulty microswitch may the cause of your tap issues, the first thing to do is to take it off the tap and use a multimeter. That will tell you if current can still pass through the microswitch when activated. As stated above, they are quite fragile little bits of plastic, and eventually, you are probably going to have to replace them. You can purchase microswitch sets with a couple of microswitches and connectors such as Whale set below:

Whale Microswitch Set

Even if a faulty microswitch is not the cause of your tap not working, its a good idea to have some to hand when they do eventually fail: Image – Amazon

Tap Issue 3 – Pressure Switch Failure

In some caravans or motorhome, the water system uses a water pump with a pressure switch. At my home, I have a whole house pump (because our mains pressure is useless). Hence, I have a big tank of water and a large pump that keeps all my taps under pressure. When I open the tap, the water instantly comes out at pressure. The same principle of this system is fitted into some caravans and many motorhomes. Instead of a microswitch located in the taps, there is a single pressure switch that services the whole water system. Again, this can be prone to failure for a range of reasons. A typical example of a pressure switch used in caravans and motorhomes is the Truma Ultraflow Smart Switch.

Truma Ultraflow Smart Switch
If your caravan or motorhome taps operate using a smart switch its generally located centrally in the caravan, typically under the seats: Image – Truma.com

Generally, fixing a pressure switch on a caravan or motorhome is not a DIY job. Its probably something your service centre is going to have to assist with. You can purchase the Truma Smart Switch from various venders online. It will cost around £70, therefore if you are going to undertake the work DIY, you want to be confident that is the cause of your taps not working.

Tap Issue 4 – Blocked Water Filters

Some caravans come fitted with the Truma Ultraflow filter inlet. With this set up renewable cartridge water filters are used. Obviously as with any filter, from time to time they are going to need attention and maintenance. Furthermore, depending on how much debris and particles there are in the base of your Aquaroll the filter may require more frequent cleaning. Remember, at least once every season you should be sterilising the water system in your caravan or motorhome. Not only is this a requirement for safe water, but it will also clean out algae which can cause filters real problems.

Truma Ultraflow Water Filter

If the water inlet on your caravan or motorhome looks like the image above, you will need to make sure the filter cartridge is kept clean: Image – Amazon

I’ve written another post just on caravan water filters, so you if you believe this may be related to the issue your experiencing I would recommend you read that post to work out which water filter you have on your caravan and which replacement caravan/motorhome water filter you need.

Tap Issue 5 – Dry Running Leading to Water Pump Damage

A submersible or on-board diaphragm pump can potentially be damaged by running dry, hence with no water supply. However, you shouldn’t worry about dry running for short periods of time. For instance, with a submersible pump when the Aquaroll is empty. Yes, you will be running the pump for a short period of time just as the water cylinder becomes empty, but that’s unlikely to lead to damage. With an on-board diaphragm positive displacement water pump, before the pump has pulled in water from the Aquaroll again it will be running for a short period of time dry.

However, what if the water pumps are left running dry for longer than the short periods of time described above? For instance, if you left a tap or shower running while unattended. Pretty much all water pumps require water passing through them to lubricate and cool the pump. Running dry will build up friction, which may damage the seals or burn out the pump. That may potentially lead to a requirement to replace the pump.

Tap Issue 6 – A Bad Leisure Battery

One potential reason the taps may not be working in your caravan or motorhome is a bad leisure battery. As referenced above, the water system in a caravan or motorhome runs from the 12V system and not your 230V mains hook up. Granted, while you are on a serviced pitch the mains hook up should be charging the leisure battery, in some cases though, it may already be damaged. Previous overuse below 50% capacity and irregular charging may be the cause of such damage. For instance, while some people like to use a 230V inverter while off-grid camping, they can easily overwork the leisure battery. Therefore its a wise investment to have a quality leisure battery charger to keep your battery healthy.

Conclusions on Why Your Tap May Not Be Working

If you have reviewed all of the information above and tried the various solutions to no avail your service centre is going to have to help you to get the tap working again. Make a note of the various checks and solutions you have tried as this will help the service centre narrow down the problem and sort the tap issue out as quickly as possible.

I hope you found this post useful and you are able to get your tap working again. I also hope you consider coming to visit us here at Horton Common to try our fully serviced pitches where you can leave your Wastemaster at home!

Chris - Site Manager

Hi, I’m Chris, I along with my father Robert we operate and maintain Horton Common.

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