Water is something you'll think about a lot when living in an RV. At a minimum, you'll be using it for drinking, cooking, and washing up. You may also use it for showering, washing clothes, making ice, and more besides. Thus, refilling your water tank will often be on your mind. But can you always trust the source you're refilling from? Even municipal plumbing can contain water contaminants you may not want to drink. When boondocking in an RV, freshwater sources may be far less trustworthy than the faucets at home. This is where RV water filter systems come in. Our handy guide will go over the different kinds of RV water filter setups and give some advice on choice, installation, and maintenance.
Shane has been teaching people to convert campervans for years; he's the author of Roaming Home; The Comprehensive Guide for Converting Your Van Into a Campervan, writer of The Van Conversion Newsletter, instructor of The Van Conversion Course over at Udemy, and a full-time vanlifer for 4 years!
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To Cut to the Chase
Water filters come in a variety of formats and, at a minimum, filter out sediment and minerals that affect the taste of your water. Further filtration steps also remove harmful chemicals and microorganisms. Our top pick for RV water filter systems is RV Water Filter Store. Their wide range of filter system types and spare parts makes them an excellent one-stop shop for everything you'll need to keep your water system healthy.
Why You Need an RV Water Filter System
Refilling your fresh water tank is a regular and frequent concern when spending time in an RV. Water can often run out unexpectedly, or in inconvenient moments. The less limited you are when looking for a refill, the better. In North America, water from municipal plumbing is generally fine to drink, but it might contain minerals and additives that affect taste and leave limescale buildup in your plumbing system. Water sources in campsites and RV yards are unknown and variable in quality. The same goes for water from wells, streams, and lakes, especially in desert areas or places with heavy agriculture and industry. Gas stations often have a freshwater hose for washing cars; this is an excellent resource for people living in vans, but the water quality is uncertain and not regulated for drinking.
Water from unregulated or poorly maintained sources may contain heavy metals, chemicals from industry or agriculture, undesirable additives like chlorine and fluorine, sediment and particles, and microorganisms. A water filter for your RV cleans the water of these substances, allowing you to refill with confidence wherever you like. Additionally, any good filter system will remove sediment and minerals that build up in your plumbing, which reduce the lifespan of expensive components like pumps, valves, and accumulators. Further, the removal of biological particles and microorganisms heavily reduces the need to clean your tanks and pipes, as there should be nothing growing in them. Finally, filtration improves the taste of your water by removing chlorine and minerals that give that unpleasant hard water flavor.
Types of RV Water Filters
RV water filters are distinguished by the type of filtration they use and the format of the filter itself.
Filtration Types in RV Water Filters
Sediment Filters
Sediment filters are simple physical barriers of mesh or porous material that mechanically filter out solid particles. These generally incorporate several different filters to clean water of sand, silt, dirt, and rust. They're often important as the first filter in any RV water filter setup as they protect downstream filters from getting clogged up. This improves their efficacy and lengthens their lifespan. Sediment filters are generally simple to maintain, as they only need a replacement of the filter cartridge at manufacturer-defined intervals.
Carbon Filters
Carbon filters use activated carbon to filter out chemicals, minerals, and heavy metals. They work through adsorption, a chemical process whereby water passes through the highly porous carbon filter structure and chemical contaminants are attracted to the its surface. These contaminants bind to the filter, becoming trapped, and allowing the cleaned water to pass through. Carbon filters effectively remove pesticides, herbicides, industrial chemicals, heavy metals, salts, fluorine, and chlorine, amongst other contaminants. Their main drawback is that they don't remove microorganisms, and thus often form a part of a more comprehensive filter system. The cartridges in carbon filters also need to be periodically replaced.
Ceramic Filters
Ceramic filters contain a ceramic-based filter medium with a very fine pore size, which is effective at removing sediment, bacteria, protozoa, and many viruses. These filters are durable and long-lasting, and some are even reusable after being cleaned. Their ability to remove almost all kinds of microorganisms make them a popular choice, though their inability to remove chemicals means they need to be incorporated into a comprehensive system.
Note that while ceramic filters remove all bacteria and protozoa, as well as larger viruses such as hepatitis and norovirus, smaller viruses such as adenovirus and rotavirus will not be removed. These viruses are typically associated with sewage and agriculture, and the risk of contamination increases with how stagnant the water source is. The choice of whether to include more complete sterilization will depend on the areas you spend time in and the sources of water available to you.
Reverse Osmosis Filters
Reverse osmosis RV water filters work by actively pumping water at high pressure through a semi-permeable membrane, which allows water through but blocks all other particles. This means that ions, salts, minerals, heavy metals, and chemicals, as well as bacteria, viruses, and other microorganisms, are all filtered out from the water. Reverse osmosis requires water to be pumped into the filter, meaning a dedicated pump is required. Further, these filters produce wastewater containing all the contaminants they filter out, meaning that both a clean and dirty water outlet needs to be plumbed in. Finally, reverse osmosis removes all minerals from your water, including beneficial ones like calcium, magnesium, and potassium. This is worth bearing in mind, as these minerals are important for our health and we normally get them from our drinking water.
Reverse osmosis RV water filters are highly effective, but are more expensive and require a more complicated installation. Further, they need more regular maintenance, and replacement filter cartridges are more expensive than for other filter types.
UV Water Purifiers
UV water purifiers work by exposing water to UV-C light from a UV light bulb as it passes through a quartz sleeve. This UV-C light destroys microorganisms and their genetic material, preventing them from multiplying in your water system. This is a very effective method for removing microorganisms, and it doesn't change the taste or pH of your water or remove beneficial minerals. However, UV light doesn't do anything to chemical contaminants.
It might already be clear that no one type of water filtration is sufficient to completely clean your water. This is where different RV water filter formats come in, as they often combine multiple different kinds of filtration into one integrated system.
RV Water Filter Formats
In Line Filters
In line RV water filters can be thought of as an expanded section of pipe containing filter media. They are installed directly into the water line with a very low footprint, generally between the freshwater inlet hose and the freshwater tank. In line filters contain a replaceable filter cartridge, which is generally a sediment filter and some kind of chemical filter. For example, this one from Omnipure incorporates a sediment filter and a carbon filter for removing chlorine, chemicals, and heavy metals. In line filters are easy to install and take up little space, meaning they're perfect as the initial filter in a more comprehensive system. Maintenance is generally as simple as replacing the filter cartridge after a certain amount of use.
Canister Filters
Canister filters are also installed directly into the water line, but the filter cartridge is contained in a dedicated canister that hangs down from the pipes. These canisters are larger and more robust than in line filters, and can often hold more than one filter cartridge. This allows for different filtration methods to be used in series. For example, this two-canister system from RV Water Filter Store incorporates two separate, individually replaceable filters, which filter sediment and chemicals (plus some microorganisms) respectively. The main benefits here are that you can replace one cartridge when its function is reduced, as opposed to having to replace the whole system, and that this system supports a higher water flow rate than in line filters. This kind of filter system is, however, bulkier, and needs to be fixed to the structure of the RV.
Under Sink Filters
Under sink filters are single-canister filters that are installed in line directly under the sink. They're larger than an in line filter but take up less space than a canister filter. Their larger size means they can incorporate a larger filter canister that can provide more comprehensive filtration. Further, they can also support a higher flow rate than in line filters. A good example is this under sink filter from RV Water Filter Store which incorporates a single canister that filters sediment, chemicals, bacteria, protozoa, and most viruses. Being a single-canister system, the entire canister needs to be replaced after a given amount of usage.
3 Stage Filters
3 stage RV water filter systems are a type of canister filter that incorporates 3 different filter types. The first two will generally be sediment and chemical filters, whilst the third will often be a microorganism filter. This third filter may be a ceramic filter for removing bacteria, protozoa, and most viruses, or it may be a reverse osmosis or UV module for complete sterilization. For example, this 3 canister system from RV Water Filters incorporates a sediment filter, a carbon filter, and a ceramic filter for removing microorganisms down to 0.2 microns in size.
Portable Filters
Portable filters get around the process of installing your RV water filter by requiring neither power nor a plumbing connection. Instead, they filter water separately from your water system and can be put away when not needed. They might be gravity-fed, incorporating a reservoir that holds water and drains it through a filter element, or they may use a pump. Bottle and straw filters also exist, which are small and compact and allow you to drink directly from a source. These filters are often found in formats that remove sediment and chemicals, and may also remove bacteria and protozoa. In general, portable filters won't have virus filtering capabilities.
I personally own the MSR Hyperflow water filter and absolutely love it. It's compact, effective and has a very high flow rate. I've used it many times when I suspect my water source to be of poor quality. In the past I used a Sawyer Straw, but I found the filter would get clogged after a relatively short time, and the flow rate was quite poor. I'm really sold on the MSR filters these days.
Choosing the Best RV Water Filter System
What Type of Filtration?
The first choice when deciding on an RV water filter system is the level of filtration you're after. We would suggest that if you're only concerned about taste, then a combined sediment and chemical filter is a good choice. This will give your water a neutral, clean taste, with the added benefit of protecting your water system from sediment and limescale.
If you're concerned about the safety of the water you're drinking, there's no good argument for only incorporating chemical filtration. Any water source that could be contaminated by chemicals could also be contaminated by microorganisms. In this case, you'd be looking at a comprehensive filter system that covers all 3 kinds of filtration.
What Filter System Format?
An in line RV water filter could be a good choice if you don't need all the water that comes into your RV to be drinkable. For example, an in line filter could be installed upstream of the water tank to protect your whole water system from sediment and minerals. You could then install a separate chemical and microorganism filter upstream of your kitchen tap, to clean your drinking water. This setup would reduce the load on the more expensive chemical and microorganism filter, reducing maintenance costs.
A 3 stage RV water filter system is a sensible comprehensive system in most cases. They take up more space and have a higher up-front cost, but have the advantage of having separate, replaceable canisters, reducing overall maintenance costs. Under sink systems can also provide comprehensive filtration, but their single canister must be fully replaced when one kind of filtration becomes ineffective. These single comprehensive canisters are more expensive than those used in 3-canister systems. The primary benefit of an under-sink RV water filter is that it takes up much less space and is simpler to install than triple canister systems.
What about UV and reverse osmosis sterilization?
Choosing these will give you complete cleaning, including all kinds of viruses. This kind of protection is only necessary if you're filling from groundwater sources (lakes, streams, rivers, and shallow wells) in areas with agricultural and industrial activity. If you truly want to be able to fill up from anywhere without worrying, complete sterilization is the only way to go. However, these systems come with a higher upfront cost, more complicated installation requiring an electrical connection (as well as additional plumbing for reverse osmosis systems), and require more expensive maintenance to replace delicate components.
Finally, it's important to pay attention to the capacity in gallons per minute (GPM) of your chosen filter system and make sure this aligns with what will be flowing through your pipes. Even low capacity in line filters are rated to a higher GPM than domestic faucets. However, the addition of a shower might put you over the GPM rating of your chosen system.
Step-by-Step Guide to Installing Your RV Water Filter
The installation process will depend on where you're installing your filter. Most filters, including in line, under sink, and canister, simply use a single water input and a single water output.
What Will You Need to Install an RV Water Filter System?
As we're dealing with plumbing, the basics you'll need to install a water filter are:
A suitable mount for fixing a canister system in place
A screwdriver
Sandpaper
Our comprehensive article on water systems goes into the different types of piping, pipe fittings, and cutters. In addition to these basics, you may also consider:
A water pump , if you're installing a reverse osmosis component
A water softener, to deal with hard water if you're not using a carbon filter
A water testing kit, to periodically check the safety of your water and the efficacy of your filter system
Once you have your materials, you can begin the installation.
Decide on your installation location, making sure there's enough room for the filter to be installed (and mounted if need be) in the correct orientation.
Make sure that any filter that isn't in line will be adequately supported and fixed in place, avoiding strain on pipes and fittings. Canister and under sink filters often have an integrated mounting bracket which you'll need to screw to a structural member in your RV.
Drain your water system by opening all valves, inlets, and outlets, and letting water fully drain out.
Measure and mark where you will cut sections of pipe to accommodate the filter in an existing system, or measure and mark the lengths of pipe you'll need to cut if installing a filter as part of a new water system installation.
Cut the pipes using an appropriate pipe cutter.
Sand the cut pipe ends to ensure smoothness with no burrs or jagged edges.
Install pipe fittings in the cut ends of the pipe (if the filter doesn't have its own fittings built-in; refer to the manufacturer instructions here).
Attach the filter to the pipe ends.
Fix the filter to the structure of the van, if required.
If using a filter that incorporates a UV light, connect this to power.
If using a filter that incorporates a reverse osmosis element, make sure you have a pump and accumulator plumbed in upstream, and a waste water drainage pipe.
Test the system for leaks by running a small amount of water through it and carefully inspecting every junction.
Maintenance and Care for Your RV Water Filter
The main aspect of maintenance is the replacement of filter cartridges. Filter cartridges (or single-unit filters) will have a manufacturer-recommended lifespan and should be replaced after this time. This lifespan will be specified either in months of usage or the number of gallons of water that have passed through the filter.
You can use a flow meter to keep track of how much water has been filtered since your last cartridge change. Alternatively, keeping a logbook of water tank refills will give you a close estimate. If you have a 70L freshwater tank, and all water passing in or out of it goes through your filter, you can simply keep a tally of the number of times you refill your tank. The tally multiplied by the 70L tank capacity will tell you how many liters of water have passed through your filter. If you're using the kind of cartridge that can be washed and reused, keep a calendar to remind yourself when to do this. The same goes for cleaning reverse osmosis membranes and UV bulb sleeves.
Make sure you have spare canisters on hand, so you can change them over as soon as you need to. Some websites, like RV Water Filter Store , offer replacement cartridges on a timed subscription service, meaning that new cartridges will arrive as your current ones need replacing.
When replacing cartridges, make sure you take the opportunity to also clean the filter housings and other components of sediment, residue, and buildup. It's also a good idea to periodically test your filtered water quality using water testing kits.
Winterization of your water system is important to take care of your water filters. If you don't store your RV somewhere heated, you need to make sure ice won't form in your pipes. Water filter manufacturers will have recommendations on how to care for your filter in winter, but generally, this will involve draining water from all your pipes and removing filter cartridges for storage somewhere warm.
Our Top Pick for RV Water Filter Systems
Our top pick for RV water filters in all their forms is RV Water Filter Store.
RV Water Filter Store has a wide range of filter systems, tested and certified to a high standard. They sell their own systems as well as selected products from 3rd parties. Their range includes most kinds of water filter systems, including comprehensive 3 stage RV water filter systems, under sink RV water filters, and in line RV water filters. They also sell spare parts and accessories, like RV water filter housings and RV water filter canister refills.
Final Thoughts
An RV water filter system isn't essential if you're confident in your water sources. If you'll only be filling up from regulated drinking water sources and fast-running mountain streams, you can usually feel safe without one. However, even in these cases, there might be residual minerals and additives in the water that affect taste and produce limescale buildup. Further, even the most pristine of mountain streams is likely to contain enough biological material to eventually produce films of algae in your water tank and other components, requiring periodic cleaning.
Water filter systems are a relatively simple and inexpensive way of preventing any of this from happening. Even without the complete sterilization provided by reverse osmosis and UV, you'll have water that you can feel very confident in drinking, and which will minimize wear and tear on your water system. Check out RV Water Filter Store to explore their range of filters and choose one that's right for your RV.
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If you're looking for some guidance with your van conversion, you might be interested in Roaming Home; The Comprehensive Guide for Converting Your Van Into a Campervan. In the 380-page book (or ebook), you'll learn directly from Shane how to convert a van into your dream home - no prior experience needed!
Until next time.