Nomad’s Guide to Water Filtration Part 1

One of the most basic aspects to being a full-timer is your water.  Now, this is a factor whether you hook up to shore water in a city, have a well on your own plot or even within your own fresh-water tank.  One question we all have to ask of ourselves is:  how clean is my water source and can I drink it?

Other questions we ask often are:

  • Will my water taste funny?
  • Will my water smell funny?
  • Is my water free of bacteria and viruses?
  • Will the water damage my RV’s water system?

If you aren’t asking these questions, especially as a full-time nomad, you should be.

Part 1: Why filter?

There are really three stages of water-to-tap that you should group these questions into: the source (the spigot from which you get the water), the path the water takes (hoses, tanks, pipes, etc.) and how long the water has been sitting in those paths.  All three of these are important.  This series is going to cover how to improve about half of the stages.  The remaining half is about cleaning and sanitizing the systems in your RV and there is a lot of material out there covering this.  I’ll include that during our wrap up.

What can we control?

Depending on your mode of RV Nomadism (long term stays at RV parks, boondocking, moochdocking, etc.), the elements of your water system will vary as to how much and in what ways we can control the quality of our water.  A park in a city or larger municipality that has a water utility in charge of moving water to you, will likely have been treated to a certain EPA required level.  That of course doesn’t mean a hill of beans though (think Flint, Michigan), so don’t take what you think is clean water as gospel!

On the other hand, if you are connected to well water, pathogens may not be your biggest concern, you may be more concerned about the hardness of the water.  Minerals can not only alter the taste of your water, but they can also damage your pipes or water heaters, clog faucet screens and leave films on all kinds of surfaces.

And wild sources, well, they are typically a no-no, due to nasty bugs like giardia and cryptosporidium, simply because you don’t know the quality of the water source upstream.  If it is stagnant water, then, definitely not potable. Note, this is also a concern for those times you are out tossing sticks out into a river or lake for your canine companions to play with.  They can be susceptible to some of the same pathogens as we humans are.

There is a lot you cannot control in your water sources so, how do you get control of your water quality?

Sanitation, filtration and purification.  We’ll be covering filtration and purification in this article but, first, how do you know what you need?

How we improve a water source

In ancient times, the only way to clean water was to boil it.  For millennia, this was the best way to assure that water was not going to make you ill or kill you outright.  Fermentation was, interestingly enough, a way to purify water since the yeast would take out the impurities during the fermenting. Typically, wines and beers of the time were a lot weaker in alcohol content, so it wasn’t about the buzz.

Other ways our ancestors would clean water was through early filtration and purification processes.  Other ways were to use plants to filter the water, or chemical additives such as aluminum sulfate or iron sulfate used by the Egyptians, or sand and gravel as a filter system in ancient India.  Technology for water filtration has existed for a long, long time.  We as individuals just aren’t taught how to do this very critical survival activity much when you have water delivered to you.

No more!  You are an RV nomad!  Take your water safety into your own hands, and we’ll talk about how to that right now.

Most of us pull into a park, hook up and drink.  We trust that the park has good water.  We shouldn’t be so trusting, honestly, but in a modern world, if the water was bad, it would be all over social media.  Still, it might be wise for all of us to have a testing kit available to validate the water quality.

Now, some things are easy to get a feel for.  Smell is always a big indicator, typically of the chemical additives in most water supplies in urban areas.  If you smell chlorine, then the water has been treated.  If it smells like stinky eggs, there is a high content of sulfur.  These aren’t very pleasant, and drinking water with either is very dissatisfying.

There are plenty of water test kits on the market.  I’m not advocating for any particular one as I am bad and do not test the water at our destinations.  You just need a good comprehensive kit that will cover chemicals, minerals and bacteria, plus the pH.  Searching for “drinking water test kit” on Amazon, hundreds will come up.

Once you know your water quality, you can look at the next aspect of the chain – making it the best water you can drink.

Making it better

First, we’ll talk about the easiest to control and improve in our water supply – filtration.  Filtration is a big word and a lot of people equate filtration with purification, but they are not one and the same.  We can think of filtration as the first step in purification.  To better understand that, we need to think about pores.

Pores?  Yes, pores.

Pores, not the ones we all hated in puberty, are the holes in the materials we use when pushing water through to capture anything we don’t want. You know, particles and things.  The size of the particles will vary from sand and twigs and such down to microscopic creatures.  So, we’ll start at the top and discuss the very first element in making our water system better – screens.

The first line of defense in our water system is the simple sediment screen.  Sediment screens are small screens surrounded by a rubber gasket.  These are the best way to keep out larger bits of debris before it even gets into your system.  They look like this:

They’ll keep particles as small as sand out in most cases.  These can be put along any part of our water system but, obviously, the closer to the water source the better, which is why it is first up.  These screens help keep a lot of your visible particles out of your water system.  It’s handy to have a few extras around in case they fail.  My water pressure regulator has one in it and, thanks to a tip from Marc at Keep Your Daydream, I have it at the spigot.

Once we get beyond the wire mesh filter, we start entering the world of microns.


Yes, microns.  A Micron is a measurement of size equal to 1 millionth of a meter or about 40 thousandths of an inch, which is pretty darned small to be sure.  As an example, a human hair is about 75 microns across.  You’d think that a filter of 50 microns would catch most everything…but, no, not really.  There are a lot of things we want to filter that are smaller.  Here is a sample chart from Portable Water Filters’ web site that shows just how small things are in microns.

Where do we begin?

Water filters can have a variety of micron ratings.  I’ve seen some that are 25-micron rated and others that are 5-micron rated.  It all begins with the complexity of your system.  Typically, I see most RV’ers have a two-canister system, like this:

Or an inline filter like this:

The former will have two filters in it. The first is a sediment filter and the second is a carbon filter, which will help with the taste as well as sediment.  The inline RV water filter will be both a sediment filter and a taste filter.  Typically, these run 10-20 microns.  To put that into perspective, you are getting grit, taste and smell improvement; but you are not getting protection from pathogens and certain metals and chemicals.

So, let’s talk a bit about how to determine how good a filter is and to do that, we’ll discuss certifications.


There are two certifications that are used, at the manufacturers’ option, to determine the quality level of water filtration and purification.  One is the NSF rating.  NSF testing is conducted by the NSF International group, a public health and safety organization based out of Ann Arbor, Michigan.   The other is ANSI, which stands for the American National Standards Institute.  Most filters will have one or both symbols and a number if they have been tested.  Knowing these numbers will help you to understand just what a particular filter will do for your water supply.

There is a ton of literature about what all the different certifications mean, but we’re going to focus on just a handful.  We are interested in numbers 42, 53, 44, 55 and 58.

  • NSF/ANSI 42 – filters rated at 42 are primarily about reducing odor and flavor issues. The most popular you might be familiar with is a Britta or PUR water filter system on your kitchen counter.
  • NSF/ANSI 53 – filters at this rating are designed to begin to filter out contaminants that have a health effect. These are most often carbon block filters.
  • NSF/ANSI 44 – you don’t see this one too much (at least in my research and shopping), but this is a water softening filter. They’ll help in getting hard water softer, so you don’t get scaling in your pipes and tanks.
  • NSF/ANSI 55 – this rating uses ultraviolet light to irradiate the water to inactivate or kill bacteria, viruses or cysts. These are expensive systems, but, an example that is making the rounds in the RV sphere is the Acuva Eco water purification system, details over at The RV Geeks.
  • NSF/ANSI 58 – this filter rating is for reverse osmosis systems that use a multi-layer semi-permeable membrane set up to remove a lot of chemicals that are EPA regulated.

The most common I see are NSF/ANSI 42 and 53 filters.

In part two, I’ll go over how our system is currently configured and discuss some of the options out there.

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