Clean Water for Health: Filtration & Herbs

by on June 26th, 2016
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Aysgarth Close Up Waterfall

Clean Water For Health:


by Sam Coffman

As healers, herbalists have a responsibility to address all causes of illness including diet, lifestyle, and environment… and to recommend treatments and remedies besides herbs when appropriate. Access to clean water is one such problem that Plant Healer’s can’t ignore, as brought to light by recent events such as the contamination in Flint, Michigan pipes and the pollution of sources by the annually increasing number of floods worldwide. The following article is an excerpt from the Summer issue of Plant Healer Magazine, offering important information and materia medica for those of you not yet subscribed to our quarterly. Its author, Sam Coffman of the Human Path School, brings a wealth of practical info and beaucoup  experience to this and other vital topics.


Water is vital to life, as we all know.  Often, for those of us living primarily in a first-world environment, we take water completely for granted.  Turn on a faucet and water appears as though it were magic.  Flush the toilet and it just disappears.  Where it comes from, where it goes to and what happens to it in the meantime are all processes that are – most of the time and for most of us – completely disconnected from our daily lives.  Between our disposal of wastewater and what we pull from the tap, water in our first world, urban environment goes through filtering processes, destruction of all biological, living material, accumulation of numerous pharmacological and chemical toxins that aren’t filtered out, deposition into ground water and eventually back into our kitchen sink.  This is a far cry from the wild water coming out of a spring in the ground (which may have its own set of organisms that could overwhelm our body), and there are many humans –particularly in our country – who have never consumed any kind of water except the kind that comes out of a tap somewhere after being on the aforementioned journey through a public water system.

Flint Water Protestors

Whether wild water or tap water however, there are several important points to ponder on the topic of water and health:  What is the state of our water (i.e. quality and quantity) both in this country (USA) and around the world?  What can we do on a personal level to enable better water quality and quantity? How can we deal with water-borne illness? The World Health Organization estimates over 800,000 deaths per year due to water-borne diarrhea alone.  

When I first started doing medical work in developing nations it struck me as odd that a medical  mission would involve treating diseases that were obviously related to the quality of the water (e.g. parasites, kidney and urinary tract diseases, liver issues) without even so much as considering the need to address ways to change the source of the problem.  I saw so much of this that I realized any realistic health care effort in any community (anywhere on the planet) has to include water quality.  To take it to the next level, if you want to set up any kind of clinic and provide any kind of meaningful health care as an herbalist, you absolutely must have clean water at your disposal.

Sam Coffman Water Purifying Project

As herbalists in the USA this may not seem that this is an issue for you.  You can buy distilled or filtered water and have exactly what it is you need (whether to drink or use for medicine making) right at your fingertips.  However, herbalists have the extra responsibility of understanding health from the most organic and basic fundamentals.  This starts literally with at least knowing something about the source of healthy food and water.  Water quality (and quantity) plays a central role to any clinic you set up – whether in the middle of an urban area or in remote wilderness.

This article will focus on water purification methods and herbal strategies for water-borne diseases. The means to purify water are numerous, and depending on what kind of technology is available to you, can vary from primitive to advanced. Purification methods can be chemical (manufactured or even phytochemical), heat-based, radiation (UV) based and particulate filtration. One of the most reliable methods is heat.  Roughly speaking, if you can heat water to over 160 degrees F for at least 30 minutes, or above 185 degrees F for 5 minutes, or bring water to a rolling boil at all, you have created enough heat to purify water.  However there is at least one caveat to this.  You still should clean the particulate matter (turbidity) out of the water as much as possible before heating.  The clean the water looks, the better the results will be that you achieve by heating.   Another note about heating is that this will probably not remove chemical contamination.  The purpose of heat is to kill pathogens.Water borne Bacteria magnified

Aside from heat there are many other methods of water purification:   These include reverse osmosis, ultraviolet, ozone, ceramic, ion exchange, copper-zinc systems, distillation and more.  Many of these systems rely upon technology in order to be effective to any scale and are outside the scope of this article.

However, I would like to briefly cover one of the simplest and most effective water purification methods I know of that can be implemented even in a completely off-grid environment.  This method is called slow sand filtration and is a way to filter water very sustainably for a home, a clinic or a small community.

Slow sand water filtration is the type of system that the non-profit organization we work with and support (Herbal Medics) has built in villages and urban and rural clinics in Central America.  These systems are bulky and take a bit of labor, but they can be easily constructed using local materials just about anywhere in the world.   Building one together with a community is an excellent way to teach others how to set up their own sustainable water filtration system, because anyone helping will know how to do it for themselves by the time you are finished setting up the first system. The most difficult part of building slow sand filters is finding clean (food grade) water barrels and some kind of piping such as PVC.  We have set up prototype systems using tubing that consisted of bamboo connected by bicycle inner tubes, but PVC makes a much longer lasting and robust system of course.

There are a few critical concepts involved in the construction of a slow sand filtration system.  First, the most active part of this filter (within about 3 weeks after running water through it) is the biolayer of the filter.  Once this layer has formed, you do not want to starve it or dry it out.  Second, the vertical column length of sand is important.  Skimping on this distance will greatly diminish the quality of your filtration.  Finally, the flow rate (drip rate) of water through your filtration system is critical.  If water percolates too quickly through the filter, the amount of filtration that occurs will be greatly diminished.

So what are the details of these critical concepts and how can we make a slow sand filtration system?

At its most basic level, the slow sand filter consists of a single container (a 55 gallon, food-grade barrel is perfect) that has enough height to allow for at least 30” of sand.  From top to bottom, the filter has sand for at least 30” and then gravel (pea gravel size) for the bottom several inches.  The gravel at the bottom is primarily to keep the plumbing from becoming clogged with sand.

Sand Filter poste

At the bottom, we have to have some type of outlet for the water to come out.  The best way to do this is by using PVC pipe and drilling holes in it.  Making a “U” shaped PVC collector at the bottom using ½” or ¾” PVC works well. This then merges to a single pipe that exits the barrel (along the side) an inch or two above the bottom.  From here, the drain pipe needs to make a 90 degree turn back up to the top of the barrel on the outside.  This allows for a pipe (1” – 2” diameter) that we can fill with small chunks of charcoal.  A screen on either end of the pipe fittings keeps the charcoal from coming out into the water.

The important idea here is that the drain pipe final level (back near the top of the filter) is between the top of the water and the top of the sand.  In this manner, the top layer of sand should always be under water.  This allows our biolayer to form.  The term “Schmutzdecke” (also called “filter cake” in English) is a living layer of organisms that form within about 21 days after running dirty water through the filter.  This living layer of bacteria, viruses, fungi and other microorganisms, eat the pathogens that are in the dirty water coming into the filter.  I would note however, that even without waiting 21 days for the filter cake to form, I (and my teammates) have drunk absolutely noxious water (prior to filtration) that has been filtered through the sand filter, and have never suffered any ill effects whatsoever.  This has been necessary from a liaison perspective.  When we set up a slow sand filtration system for a community somewhere, it’s not very effective (socially) to tell them that in 21 days everything will be fine, while waving goodbye.  I have to demonstrate the effectiveness of the filter before we leave if we are to have any credibility as an organization.  Once we have run about 100 gallons through the filter and the water is clear coming out, it’s time for me (and whoever is in charge of the primitive engineering team, at a minimum) to do a “bottom’s up” raising of the glasses and drink away!  This is usually followed by a lot of laughing and joking and everyone else drinking water from the new filters.  I am never worried about the locals, as they’re getting far better filtration even without any biolayer formation, than they were getting prior to us setting up the filter in the first place.

Slow_sand_filter diagram 1

In order for the filter to work correctly, the flow rate needs to be kept between 3 and 5 gallons per hour.  This limits the amount of water that a community can draw from a filter.  The maximum that a filter like this is good for, is about 120 gallons per 24 hour period, and in order for there to be 120 gallons per day, it is necessary to add a couple of pieces to this filter setup.  

First, a raw-water (pre-filter) container is necessary.  This is where the dirty water is pumped or scooped into, and can be any size.  The larger the better, and in a typical gravity fed system of course its outflow will have to be positioned slightly higher than the filter’s in flow.  The manner in which the water flows into the top of the filter needs to be controlled so as not to disturb the top of the sand too much.  This is normally done using baffles (PVC pipes with holes drilled in them something like drip irrigation systems).  We usually take a few $8.00 float valves with us when we’re setting these up, as it is the easiest way to control the flow between the raw water container and the filter.  There are certainly other ways, but the float valve makes everyone’s life easier and is so simple to install as a valve that opens and closes based on the level of water in the filter tank itself.

Slow-Sand-Filter diagram

Next, a final collection tank is necessary if you want a 24/7 water filter functionality.  The collection tank is fed directly from the filter.  This means that the full filter setup is a 3-container system:  A container for the raw water, the filter itself and a collection container for the water that has been filtered.  To use the system, a person first takes the water they need from the third container in the system – the collection container with clean water in it.  If there’s not an automatic system that fills the raw-water container, that same person can get the same amount of water they just used and put it into the raw-water container.  For instance, pulling it from a well and refilling the raw water container after taking the clean water from the filtered water container.  This ensures a 120-gallon per day maximum capacity of the water filter.  Calculating 1 gallon per person per day drinking water only, this system can serve over 100 people in a community.  However, we usually set up one filter for every 20-30 people, which allows for a minimum of 4 gallons of filtered water per person per day.


This approach gives me, as an herbalist, an entirely new approach to working with a community where a hugely disproportionate percentage of the population has the same health issues that are obviously related to poor water quality.  Between fracking, coal mining, corporate agriculture and political corruption (i.e. Flynt, MI), water quality is not something that is limited as a problem to only developing nations.  So if you are researching the health issues of a given community and are facing some type of water-borne epidemiological syndrome, then following along the same logic that a clinical herbalist should be using (work with the core problem whenever possible rather than just palliating the symptoms), this may give you another tool in your toolbox to consider using.

Let us address water-borne disease now, and some of the herbal approaches to resolving these disease states.

First, what are the common water-borne pathogens?  We can become ill from water that contains viruses (for example: hepatitis A and E), bacteria (for example: cholera, shigellosis), protozoans (for example:  giardiasis, cryptosporidium) and helminths (for example:  roundworm, tapeworm).

While it is possible to run down a list of specific pathogens and cite studies (whether valid studies is a whole different question) as to the effectiveness of a particular herb used for a specific pathogen, I think it is more effective to start the discussion with some of the general approaches we can take in the case of exposure to water-borne illness.  

First, the ubiquitous, acute onset of gastroenteritis that probably comes to everyone’s mind when discussing water-borne illness.  Narrowing down a set of options is a lot easier to do once we have gathered some information using even as simple of a mnemonic as SAMPLE:  Signs and symptoms, Allergies, Medications, Last known intake (food and water) and last known menstrual period if appropriate, Events leading up to the illness.  In addition to SAMPLE we can also use OPQRST to narrow down specifics on pain or discomfort:  Onset, Palliate/Provoke (“what makes it better or worse?”), Quality (“throbbing,” “sharp,” “burning”), Radiate (“does the pain radiate to other parts of the body?”), Severity (“on a scale of 1-10 with 10 being the worst pain you’ve ever felt in your life…”), Time (“how has the pain changed with any of the previous questions, since it started?”).

Bear in mind that beyond just working with one individual, you may be watching for patterns in a clinical environment.  After the third or fourth person comes in with the exact same symptoms, you have to start addressing community health questions.  How you go about doing that can range from quarantining (in the case of something like cholera) and helping set up water-treatment & hygiene plans in a remote or post-disaster community, to contacting local (e.g. county) health officials in a more first world setting.


In acute presentation of gastroenteritis, the herbal protocols are often going to be symptom-based.  Is there nausea and vomiting?  If so, can they keep anything down at all?  Dry heaves?  Blood? Diarrhea?  Color and consistency of the diarrhea if so (e.g. “rice water,” bloody, mucous, etc.), cramping?

Our primary concerns in the case of an acute onset of severe gastroenteritis (assuming that the herbal approach is the only option for whatever reason) are to prevent the patient from dehydration and support the recovery of the gut mucosa.  The latter is simple in theory but not always in practice.  Some of the most effective approaches involve helping clear the gut of what is causing the problem and reducing the inflammatory responses.  

Activated charcoal is a very useful substance in the initial clearing of the gut.  Whether toxins (e.g. food poisoning), bacteria or even protozoan infections, charcoal adsorbs and also helps to slow diarrhea.  As an initial protocol before giving any herbs, charcoal can often be very helpful.  The dosage can range as between one and two grams of charcoal per kilogram of body weight, every 4 – 8 hours.  Be aware that the person’s feces will likely come out black, and it should slow diarrhea somewhat.  Normally (in the absence of diarrhea), it is important to note that charcoal can cause constipation.  Note that we would not want to ingest charcoal at the same time as any herbs we were taking.  Much of the herb would bind with the charcoal, rendering both the charcoal and the herb ineffective.

Moving into herbs, what are some of the primary considerations?  We want to reduce gut inflammation.  We want to help restore normal gut mucosa function.  We want to overwhelm or kill off causative pathogens.  We want to support liver and kidney function (detoxification and elimination).  We want to palliate symptoms like cramping and nausea.  We also want to prevent dehydration, which involves both a rehydration solution as well as helping the gut absorb the fluids.  

“Gut inflammation” is a sort of generic term given to the physiological set of responses by the gut to a disruption in healthy function.  Pathogens have many various methods of fulfilling their own life cycles in their own quest to survive, colonize, feed, reproduce and find more hosts.  During that process that may be happening in our own gut, there is inevitably going to be an inflammatory response by damaged tissue of the gut.  Anything that reduces the pathogenic potency, increases our own tissue healing curve or both is going to reduce gut inflammation.  

Most berberine-containing herbs kill handle many of these aspects of dealing with gut inflammation.  They provide an astringency that helps reduce water loss.  They tend to have a directly anti-inflammatory effect on the gut.  They are usually anti-microbial.  They are also usually stimulate and support liver function.  Herbs that fit into this category are the Berberis and Mahonia species.  Other herbs include Goldenseal (Hydrastis canadensis) and Chinese Goldthread (Coptis chinensis).  My favorite herb to use for acute gastroenteritis is Algerita (Berberis trifoliolata).  The root of this plant is intensely bitter and yellow with berberine, while the leaf is somewhat sweet, a little sour, and an excellent anti-nauseal.

Another herb that is highly anti-microbial, astringent and wound-healing on the gut is Walnut (Juglans spp.).  I use the Juglans microcarpa here in central TX but the most commonly used medicinal species is the Juglans nigra.  I like to mix the unripe (but just starting to soften) hull with the leaf of this tree, about 50/50.

Juglans nigra Eastern Black Walnut

Andrographis (Andrographis paniculata) is not a North American plant, but can be grown here in the most southern climates, or grown in pots and wintered indoors.  It has been referred to as the “king of bitters,” and for good reason.  Aside from its overwhelming bitter qualities, it is another herb that is highly antimicrobial and has an astringing, anti-inflammatory effect on the gut.

I like to use Wormwood (Artemisia absinthium) as well as its milder cousin, Western Mugwort (Artemisia ludoviciana) for acute gastroenteritis as well. Both are antimicrobial, anti-inflammatory to the gut tissue, bitters and cholegogues. Both are also decent anti-nauseals, even when a person is already vomiting.  

Another antimicrobial that is also a superlative smooth muscle relaxant for cramping is Silktassel (Garrya spp.).  I know of herbalists who have used the leaves of this plant to mix with water as a form of water purification.  While I have not used it this way, I do use it quite often as an anti-spasmotic for smooth muscle throughout the body, to include the gut.  I use the leaf and bark of this plant, tinctured fresh.  I usually harvest it by pruning a bush and taking all the leaves and bark off of what I prune.  This usually comes out to being about 70% leaf and 30% bark.

Any mucosal vulnerary is going to have a soothing, anti-inflammatory effect on the gut.  This can include Marshmallow (Althaea officinalis) root and leaf, Prickly Pear (Opuntia spp.) cactus flower, Comfrey (Symphytum officinalis) leaf (if you don’t have a problem with the pyrrolizidine alkaloids, which another topic), Plantain (Plantago spp.), Licorice (Glycyrrhiza spp.) root and many others.  These are best prepared as a cold infusion, which also helps with hydration.  If you are preparing a rehydration solution anyway (1 teaspoon salt, 6 teaspoons sugar per quart of water is one of the most basic formulas), you can put it all together in a mucosal vulnerary rehydration drink.  

As a side note, Prickly Pear cactus can be used to filter water as well.  Fillet the pad and chop it into small pieces so that lots of surface area is exposed of the demulcent, gooey inside of the pad.  Put those pieces into a container with the water you wish to clean (pre-strain to clear as much turbidity as possible).  Shake, let it sit about 30 minutes, shake again and strain.  It is not anywhere near the filtration of a slow-sand filter, but the Prickly Pear pad is a flocculant and will stimulate aggregation of small particulates (fomites – homes for pathogens to live on) into larger particulates while adsorbing the same.

In a pinch, the Prickly Pear cactus pad can even be used to boil water!  Take a large pad, cut off the pointier end, fillet down the center very carefully to within about an inch of the edge (from the inside).  You can prop the sides open at the top using a small stick and pour water into the pad.  Water can be heated to easily 160 degrees for about 30 minutes in coals, without burning through the pad

All of the antimicrobial herbs mentioned above are going to give relief and help the body cope with a protozoal infection such as giardiasis or cryptosporidium.  Another strong antiprotozoan for those two infections particularly, is Chaparro Amargosa (Castela spp.).  



Black Pepper (Piper nigrum) is another anti-protozoal and one of the primary ingredients in formulas I have used to work successfully with cutaneous leishmaniasis infections, which are protozoal.

With any case of infectious gastroenteritis, it is imperative that the liver and kidneys be supported as well.  Support of the liver should be gentle to help it detoxify waste products that make it into the hepatic portal system.  Milk Thistle (Silybum marianum) seed is of great use here.  Also helping to support liver function gently are Chicory (Cichoreum intybus) root and Artichoke (Cynara scolymus) leaf.  I like to use Burdock (Arctium lappa) root and Dandelion (Taraxacum officinalis) root a lot as both gentle liver support as well as gentle diuretics whenever helping the body deal with toxins, pathogens, infection, lymph stagnation or other disease processes that increase the body’s need to deal with and excrete waste products. 

Parasites (helminths) are another topic that is a discussion on its own.  There is generally not going to be a singular herb or even a set of herbs that are anti-parasitic for all parasites across the board.  However as a rule, some of the general anti-parasitic herbs that work in formulas either directly, or supportively, are: Any of the aforementioned berberine-containing herbs, Elecampane (Inula helenium), Horse Radish (Armoracia rusticana), Black Pepper (Piper nigrum), Wormwood (Artemisia absinthium), Ginger (Zingiber officinale), Valerian (Valeriana officinalis), Prickly Ash (Zanthoxylum spp.), Andrographis (Andrographis paniculata) Garlic (Allium sativum) and Cayenne (Capsicum annuum).

The importance of clean water cannot be overstated in the full spectrum of holistic understanding of our health.  In the case of infectious disease, it is paramount that we have a clear understanding of both the epidemiology of the area as well as the tools we can implement to create better preventative health for a community.  Once we have helped create sustainable, clean water, we can continue even better than before as herbalists and health care providers.


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