How to Sterilise a Caravan or Motorhome Water System

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

Every now and again we have caravan beginners at Horton Common with a new/secondhand caravan or motorhome asking questions about how to clean their water system. Often the dealer will have mentioned briefly that they should sterilise the caravans water system, but the dealers generally don’t really provide any more detail than that.

I’ve briefly touched on how to sterilise a caravans water system in how to set up a caravan on site. However, with this post, I thought I would go into a bit more detail on how and why you should sterilise your caravans water system. First I’ll provide the highlights in a step by step manner, then I’ll go into the topic in a bit more detail.

How to Sterilise a Caravan or Motorhome Water System

  1. Purchase a tub of Puriclean

    Puriclean is specifically designed for washing out and sterilising a caravans water system. Don’t be tempted into using Milton sterilising fluid, it’s not designed for the job. In fact, Milton could end up doing more harm than good to the water system.

  2. Half Fill your Aquaroll/Water Hog and add Puriclean

    For a full water system clean and sterilisation, you will need to add 8-9 teaspoons of Puriclean to the Aquaroll/Water Hog. Once you have added the Purilclean fill the container up to the top with water, a quick shake and then let it sit for a while.

  3. Remove the Caravan Water System Filters

    Before you pump the sterilised water through the caravans water system you will want to remove the water filters. Puriclean will breakdown and dissolve the filter membrane.

  4. Close all the Taps and Prime the Water System

    Make sure that you fill up both the cold and hot water tanks, but don’t turn on the hot water heater. Open each tap and let some of the sterilised water flow out of the taps. Then shut the taps and let the Puriclean do its job.

  5. Leave the Puriclean to work for between 1 to 12 Hours

    Obviously, there is a significant difference between 1 to 12 hours. How long you leave the Puriclean in the water system to sterilise is a personal preference. You should consider how long the water system has been sat idle since last used.

  6. Flush Through the Water System until Empty

    Now go around each tap (including the shower) and empty out the whole contents of the Aquaroll/Water Hog. Try and make sure each tap gets a fairly equal amount of the sterilising water flowing through it.

  7. Re-fill the Aquaroll/Water Hog and Wash Through

    You will now probably want to re-fill and flush through the caravan water system 3 to 4 times to remove any taste of the Puriclean. Again, make sure you do this with each tap.

  8. Re-install and Potentially Replace the Water Filter

    Now the caravans water system is clean you can now re-fit the water filter. Check the manufacturer’s instructions for how often you should replace the caravan water filter. You can now use the caravans water system as normal.

Disclaimer: Hey! By the way… any links on this page that lead to products on Amazon or Caravan Guard are affiliate links and I earn a commission if you make a purchase, with no additional cost to you.

This video provides quite a good summary of the process of how to sterilise a caravans water system.
Elsan Organic/Green Toilet Fluid for Caravans/Motorhomes
3,245 Reviews
Elsan Organic/Green Toilet Fluid for Caravans/Motorhomes
2 Litres
Suitable for all Chemical Disposal Points (CDP)

How often should you Sterilise your Caravan or Motorhome Water System?

Now how often you choose to sterilise your water system is a matter of personal preference. However, as a minimum, you should sterilise the caravans water system once a season. If you are in the caravan quite frequently, say once a month or two, you may find once a year sufficient. If there are gaps in your use of the caravan for more than a couple of months at a time it’s not a bad idea to sterilise the water system again.

Puriclean is made specifically for cleaning and sterilising caravan and motorhome water systems: Image –

One method could be to do a once season sterilisation and leave the Puriclean in the caravans water system for up to 12 hours before you set off on your trip. Then every couple of months you could do a quick clean for just 1 or 2 hours. For instance, you could leave the water system to sterilise while you level the caravan or motorhome.

What if you don’t use your Caravan Taps for Drinking Water?

Now, quite a lot of caravanners don’t actually use their caravans water taps for drinking water. They will have a small portable water container of say 5L which they have inside the caravan. This is why at Horton Common with our fully serviced pitches we fitted two taps.

One tap is for the permanent water connection to top up the Aquaroll and the second is for separate water containers. Therefore our visitors do not have to disconnect the permanent water connection to fill up their portable drinking water containers.

Fully Serviced Caravan Pitch
We provide two taps at Horton Common per pitch. One for a permanent water connection the other to fill portable drinking water containers.

If you don’t use your caravans water system for drinking water do you still need to sterilise it? Well yes, when you wash your hands you wouldn’t want to add germs instead of washing them away. Also, if you don’t sterilise your caravans water system you could have issues with a build-up of biofilm.

Biofilm is a combination of bacteria and fungi that can grow on surfaces. You may have noticed on the inside of a hosepipe that slimy residue, well that’s biofilm. If you don’t sterilise your caravans water system you could be washing your hands and cookware in biofilm residue! Don’t forget about your shower, I’m sure you don’t want to shower in water contaminated with bacteria either.

Are there Alternatives to Puriclean?

Sure, there are various other brands of water sterilisation additives. However, make sure they are suitable for caravan water systems. Some water sterilisation liquids that many people are familiar with, Milton being an example can actually do damage.

Milton Sterilising Fluid
Don’t be tempted to use Milton Sterilising Fluid. It could damage your caravans water system.

Milton attacks metal surfaces. If you read the label on the back of the bottle you will see the warnings. Therefore using Milton could cause corrosion issues with certain parts of your caravans water system. We personally use Puriclean in our caravan and most of our guests also use Puriclean in their caravans.

Puriclean is not expensive and I feel it does a good job at sterilising the caravans water system. In my post on motorhome water systems, I also discuss the use of citric and acetic acid.

Conclusions on How to Sterilise a Water System

Hopefully, you found the above information useful. I must admit, I’ve had quite a few caravanners who never used to sterilise their caravans water system until they started to notice a strange taste in the water! You don’t want to leave it until that point, make sterilising your caravans water system a part of your preparation before going away and while setting up on-site.

I also hope at some point in the future you consider coming to visit us here at Horton Common to experience our excellent views of the Staffordshire Moorlands and Peak District National Park. 🙂

Elsan Organic/Green Toilet Fluid for Caravans/Motorhomes
3,245 Reviews
Elsan Organic/Green Toilet Fluid for Caravans/Motorhomes
2 Litres
Suitable for all Chemical Disposal Points (CDP)

Chris - Site Manager

Hi, I’m Chris, along with my father Robert we operate and maintain Horton Common Caravan Site. Located in the Staffordshire Moorlands Horton Common benefits from expansive views over the Peak District National Park. Horton Common features five hard standing fully serviced pitches for caravans and motorhomes.

Recent Posts