BOS is all about home water treatment. That’s not only water filtration and purification. It’s also water heating, water cooling, storing, distribution… – the list goes on.
This guide shall provide you with a general introduction to the topic and a not-so-brief summary of what you can expect to find on this website.
We’re going to start with water filtration, our main focus.
Water filtration is one of the many forms of water purification. It covers physical, biological and chemical methods to remove undesirable substances from water using a filter medium. Other forms of water purification include sedimentation and distillation, but also chlorination and UV light radiation for disinfection.
The goal of water filtration/purification is usually to produce water safe for human consumption which is also what we are going to discuss here.
What can be removed? It depends on the filtration process, but generally speaking, all kinds of biological contaminants, chemicals and suspended solids.
Why should you even bother and filter your water in the first place? Doesn’t the government regulate public water quality?
Yes, the U.S. Environmental Protection Agency (EPA), an independent institution of the United States federal government responsible for environmental protection, has set national legal limits on more than 90 different contaminants in drinking water – in accordance with the Safe Drinking Water Act (SDWA).
Currently regulated contaminants are
Safe Drinking Water Act? As a federal law, the act was passed to protect public health by regulating public drinking water supplies, which also includes its sources, so lakes, rivers and the like.
In theory, this should protect us against potentially harmful natural and man-made contaminants that can be found in our waters. After all, the legal limit for a certain contaminant reflects the level protecting human health. But it also reflects the manageable level water systems can achieve which is often conflicting.
In other words, public water filtration is also a question of feasibility which boils down to cost. And this is the first problem: Who guarantees that all dangerous substances can indeed be removed from our water supplies at a large scale?
Secondly, even if they can be removed, who says that they will be removed? And this has nothing to do with conspiracy theory either. Sometimes, all that’s needed is some human failure. Remember the Flint water crisis? It has shown us that, depending on where you live, there might be contaminants present in your tap water that pose a serious threat to your health.
To top it all off, USA Today identified about 2,000 water supplies in all 50 U.S. states where tests have shown severe lead contamination between 2013 and 2016. According to the Detroit Free Press, hundreds of major U.S. cities still have 100% lead piping. And The Guardian found at least 33 cities that have cheated to conceal dangerous levels of lead in their water – enough said.
The next issue is there are many, many contaminants currently unregulated by the EPA. We miss legal limits for more than 160 substances, says the Environmental Working Group. Compare that to the 90 contaminants that made it on the EPA’s list. And even for those the legal limit is often tens or even hundreds of times higher than what up-to-date scientific research suggests.
Or the regulation is simply ineffective as is the case with chromium 6, a metal that is both toxic and carcinogenic in tiny dosages. Currently, there only exists a federal limit for total chromium, so chromium 3 and chromium 6 combined, at 100 parts per billion. Funnily enough, chromium 3 does not even pose a health risk. The California Office of Environmental Health Hazard Assessment (OEHHA) has set their public health goal for just chromium 6 at 0.02 ppb. This is expected to cause no more than one case of cancer in one million people who drink the water for a lifetime.
One issue affecting people on private wells alone is that the SDWA does not apply to water systems serving fewer than 25 people or with less than 15 service connections. So if you have your own private well you yourself are in charge to ensure the quality of your water is up to standards.
The last factor we want to mention is water getting contaminated on its way from the treatment utility to your home. In fact, that’s what was causing the lead problem in Flint. The city has had an outdated water system with thousands of service lines containing the heavy metal.
FYI: Before the lead ban in 1986, solder and pipes containing lead were used in public water systems.
The good news, Flint city experts expect to finish replacing all remaining lead lines by mid 2021. The bad news is that too many cities have underfunded water systems.
Bottom line, there are many reasons to filter your water, unless it’s already clean…
It’s easy to detect the typical bleach characteristics of high chlorine or chloramine levels. In excess amounts, chlorine in particular makes water taste and smell like a swimming pool.
A bitter or metallic taste is often caused by acidic water accelerating the corrosion of your plumbing system and leaching metals out of pipes and fittings. The corrosion could result in elevated lead levels, so nothing to take lightly. If you are on well water, naturally occurring iron and manganese could be the culprits of an almost blood-like taste.
Rotten egg smell might indicate a problem with sulfur bacteria and hydrogen sulfide. Earthy, musty or moldy water could mean seasonal algal blooms, bacterial growth, or decaying organic matter in the source water or the soil the water filters through in case of well water.
Your water tastes salty? It could be high levels of chloride, sulfate, or overall TDS.
It’s also a good idea to do a sight test. Fill a glass of water and hold it against the light. Can you see any floating particles? How about discoloration or cloudiness? Lastly, have you checked the condition of pipes, fixtures, bath tubs, toilet bowls, etc. lately?
All in all, trying to find hints for an underlying water contamination issue using your senses can work, but it’s not always an option. For example, you can’t smell, taste nor see lead in concentrations of parts per million or even parts per billion.
So how can you find out if you really need a water filter? There are two ways:
Checking the quality of your water by testing a direct sample is the safest method to detect potential contamination – if done right.
You can do your own testing using one of the many available test kits. However, results may be inaccurate. Also, most test kits focus on certain contaminants or contaminant groups but seldom cover the entire bandwidth. This method is ideal if you need fast results and/or you suspect to find certain impurities you want to test for.
Having your water tested by a professional lab is our go-to method. It promises the most accurate results and you can choose between basic testing and a more thorough analysis. Furthermore, the experts can advise you on the most important and most suitable testing. An obvious downside is the high cost.
Another alternative is contacting your local municipality. They sometimes provide free testing or can provide you with more information on the matter.
Instead of or in addition to testing, you can find out more about the quality of your water by checking previous Water Quality Reports also known as Consumer Confidence Reports.
Each year you should receive such a report from your local water supplier via mail free of charge, as per a 1996 amendment to the Safe Drinking Water Act. The report lists all regulated contaminants as well as those for which monitoring is required that were found in your water in the last 12 months, and at what levels. Additionally, for any regulated contaminant for which there has been a violation of the legal limit, a brief statement regarding the health concerns must be included.
The overall goal is to allow you to make your own health-based decisions regarding your drinking water consumption.
Personally, we like the idea of free Water Quality Reports. But what about all those unregulated contaminants that are not on the watch list either? And, again, what if the water gets contaminated on its way to your place?
You now know how to determine whether or not you need to filter your water. Where do you go from here? After all, there are dozens of different water filter types, filtration methods and filter media, and thousands of water filter products to choose from.
With water filters, the selection ranges from small, inexpensive pitchers to pricey whole house systems. The most straightforward way to categorize them is by their intended purpose. There are drinking water filters (water may also be used for cooking), shower filters, and whole house water filters. Other applications include filling one’s fish tank with purified water, or commercial purposes such as filtering water for a car wash.
We focus on water filters for home use.
Filters or filter systems that provide water for direct consumption – drinking and cooking – can be grouped into
We will also mention water distillers, although strictly speaking distillation is not a form of water filtration but of water purification (more on that later).
When it comes to shower water filters, there is no need to separate them any further. Most combine numerous treatment methods to get the most out of your water. The same goes for whole house water filters.
Speaking of treatment methods…
Microfiltration, ultrafiltration, nanofiltration, reverse osmosis – with water filtration the separation of solid matter from water is achieved by using a filter medium with a complex structure. The water molecules pass through the pores, but some or most solids can’t simply because they are too large in size. That’s the whole secret.
By the way, you may have heard of activated carbon or charcoal water filters. However, activated carbon adsorbs contaminants not due to physical size but due to surface charge. So adsorbers would be the better term here. We will continue to use the term filter for the sake of simplicity, though.
Water softeners are also sometimes called water filters or categorized as such, although their ion exchange resin works on the same adsorption principle as activated carbon. We will discuss water softeners later in this guide.
In water purification, there are depth filters and there are surface filters. An example for the latter would be a reverse osmosis membrane which acts as a solid barrier that rejects oversized particles. Depth filters use a bed of filter media which can be granular or solid. The media traps contaminants as the feed water flows through them.
Generally speaking, thanks to their greater surface area depth filters are less prone to clogging which increases longevity. A small surface area and thus higher risk of clogging is why most surface water filters should be combined with pre-treatment.
Surface filters are rated in microns. For example: A sediment pre-filter with a micron rating of 25 traps all contaminants larger than 25 microns. Other common ratings are 50, 10, 5, and 1, followed by the sub-micron level.
The dilemma: The smaller the micron rating, the lower the maximum water flow rate. This is why you won’t find many whole house reverse osmosis systems. Regular RO membranes have a micron rating of 0.0001 reducing water flow to a trickle, unless enough external pressure is applied.
Sediment water filters are good at removing suspended particles like sand, silt, rust, dust, and scale. An RO membrane rejects up to 99% of all water contaminants including salts, heavy metals, bacteria, viruses, chemicals and organics.
Sediment pre-filters can be made of a variety of materials. Most common are cellulose, polypropylene, polyester, cotton, and ceramic.
The majority of commercially manufactured reverse osmosis membranes are thin-film composite (TFC), cellulose acetate (CA) or cellulose triacetate (CTA) membranes. TFC membranes are more durable than CA and CTA membranes and also have higher rejection rates, 98% on average for the common contaminants. Therefore, CA and CTA membranes are better at tolerating chlorine, but more susceptible to fouling from bacteria.
Each membrane is made up of a flat sheet rolled around a perforated core tube where the permeate water is channeled into. A membrane flat sheet has 3 layers: First, the active barrier skin about 0.2 microns in thickness, followed by 2 support layers about 100 microns in thickness that strengthen the very thin barrier layer.
The following list includes filter media using all kinds of water purification methods, not just filtration.
About NSF Certifications
When shopping for a water filter, watch out for NSF certifications. There are different standards that guarantee a filter’s capability to reduce one or more specific contaminant under real-life conditions simulated in a laboratory.
Most important are
A whole house water filter, or point-of-entry (POE) water filter, treats all the incoming water before it gets distributed throughout your home. The main goal is to remove the basic contaminants, sediment and chlorine comes to mind, to improve water aesthetics and protect water-using appliances.
A whole house water filter can also be used with specialized filter cartridges to eliminate harmful contaminants – think heavy metals such as lead – making water safe for consumption.
Whole house filters that reduce hardness provide for slightly softer water for less staining on surfaces, soft clothes, and healthier looking hair and skin. The lifespan of your plumbing system, washing machine, and dishwasher etc. might increase, too. For severe cases of water hardness, a conventional water softener is certainly better suited to regulate hard water minerals.
As with water softeners, one thing to remember is that whole house water filters have to have a high-enough flow rate to provide your entire home with filtered water. Otherwise you might see pressure drops at times of peak consumption. 10 to 15 gallons per minute (gpm) is pretty standard.
We’ve mentioned that reverse osmosis membranes reject contaminants based on their size. But that’s not the whole story. They also reject contaminants based on their ionic charge, the higher the better.
And there is another key difference between reverse osmosis and regular filtration: The predominant removal mechanism. Reverse osmosis involves a diffusive mechanism so that filtration efficiency also depends on solute concentration, water pressure and water temperature. Higher water pressure means higher filtration efficiency, while lower water temperature results in lower efficiency.
Under the right conditions, a proper reverse osmosis system removes almost all impurities from water, usually at the point of use. RO membranes are very delicate, though. Chlorine and other chemicals can harm them. Sediments can lead to clogging. Both results in a shortened lifespan. Thus, most under sink and countertop reverse osmosis systems for home use feature 2 to 3 different pre-treatment stages.
Post-filters give the water a finishing touch, removing residue taste and odor.
By the way, there are whole house reverse osmosis systems, but they are really expensive
In the under sink water filter category, there are reverse osmosis under sink systems and regular under sink systems. This section is about the latter.
A sophisticated under sink water filter is effective at removing a wide range of potentially harmful contaminants for clean and great tasting drinking water. With multi-stage systems, you can choose from a combination of different water filter types to match your purification needs. Combine that with affordability, convenience of use, and simple installation and maintenance, and all your water filtration dreams come true.
What’s more, the majority of under sink water filters use a dedicated faucet, just like their RO counterparts. The benefit is that you are free to switch between filtered and unfiltered water as needed. Filter cartridges are going to last much longer this way.
A word on water flow rate: The majority of non-RO under sink water filters do NOT feature a storage tank. Water gets filtered on demand. So pay attention to flow rates measured in gallons per minute.
Single or multi-stage, countertop water filters are perfect for people that can’t or don’t want to make any permanent changes to their plumbing system – think renters. Plus, countertop filters connect to any standard kitchen faucet in seconds, no tools required. This is also what makes them highly portable.
Speaking of faucet connections, it’s entirely possible that your kitchen faucet is incompatible with a countertop water filter. This is usually the case for pull out/down, handheld, sprayer-type, sensor and basically any unconventional faucet or spout. So before you spend any money, do yourself a favor and double check that your faucet is compatible. Also, you might be able to use an adapter.
And watch out for models allowing you to switch between filtered and unfiltered water to increase filter cartridge life.
With the help of a gravity water filter, you can purify thousands of gallons of water from almost any freshwater source, ideal in an emergency situation. And even outside a SHTF-scenario, gravity water filters have earned their keep in the water purification realm. We find top rated ceramic filters among them.
If you were to ask a dealer, he would tell you that the larger a gravity water filter, the better. And it makes sense: A larger system can hold more water and therefore needs to be refilled less often which is convenient.
Above that, a larger gravity water filter can host more filtration elements for higher filtration speed. And more water in the upper reservoir causes more pressure which also increases water flow.
Faucet water filters are similar to countertop water filters: Installation is a breeze without the need for tools and advanced skills. You don’t have to make any permanent changes to your plumbing system either.
One difference is most faucet water filters are surprisingly cheap. The downside is those cheap units won’t do much in terms of contaminant removal except for improving how your water tastes and smells. But there are also units applying different filtration media layers to reach maximum reduction (sediment, chlorine, heavy metals, disinfection byproducts, pesticides, pathogens…).
As for compatibility, faucet mounted water filters are incompatible with pull out/down faucets, handheld faucets, sprayer-type faucets, sensor faucets, and basically any unconventional water faucet or spout. So you better check if your faucet is compatible before you buy.
Now we come to the most popular water filter type: Filter pitchers. Why the popularity? Probably because they are super affordable, very easy to use and installation-free. And you can store them in your refrigerator for cooling.
In our opinion, a water filter pitcher is great if your water already has a certain degree of purity and all you want is give it a finishing touch – think chlorine reduction. This is simply because the filtration most water filter pitchers provide cannot keep up with that of a multi-stage countertop or under sink system.
Does that mean a water filter pitcher is not a good choice if you are concerned about certain harmful contaminants? Not necessarily. A handful of products do take care of lead, fluoride and the like.
Apart from the filtration process, water filter pitchers differ vastly in water storage volume and filtration capacity. Storage volume is measured in cups, ranging from 5 to about 11 or 12. A lower volume means more frequent refills and you’ll have to wait for the water to run through the filter.
As for filtration capacities, anywhere between 30-40 gallons of filtered water (lasts about 1 or 2 months) and up to 200 gallons (enough for 6 months) is possible. This determines cartridge replacement frequency and ultimately maintenance cost. Remember: The price tag of a water filter pitcher is secondary. What matters over the long run are replacement filter cost and lifespan.
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With refrigerator water filters the biggest question is OEM or aftermarket? Buying a genuine OEM replacement filter is certainly the easiest but also the most expensive option. Going off-brand can save you some serious money. Prices vary, but aftermarket filters are oftentimes 2, 3 or even 4 times more affordable.
On the downside, the level of water quality you get might leave a lot to be desired. In addition to that, aftermarket refrigerator water filters oftentimes have a lower filtration capacity. So when choosing between OEM and off-brand make sure to compare gallon ratings.
Another important criterion for choosing a refrigerator water filter is compatibility. Incompatible filters won’t fit your refrigerator at all or not properly, causing leakage. Do you have your refrigerator model number at hand?
If you want cleaner shower water you have 2 options:
Option 2 is less costly, obviously, and you don’t have to spend a whole afternoon getting everything up and running.
By removing certain contaminants, a shower filter can improve your shower experience a lot.
For one, a shower water filter neutralizes unpleasant odors. But that’s not all! People suffering from skin conditions such as dandruff often experience relief. Reducing your overall exposure to chemicals like chlorine can also benefit your hair and nails as well as your overall health – not all contaminants have to be ingested to cause health issues. Air enriched with chlorine vaporized from shower water can strain your lungs and cause eye irritation. And did you know that our skin absorbs all kinds of contaminants while we shower?
That being said, you cannot compare a small shower water filter to a much larger, complex filtration system. Sure, you can choose from a variety of filter media according to your needs, carbon, KDF, and vitamin C are prominent examples, but don’t set your expectations too high.
Portable water filters are essential for backpackers, hikers, campers, travelers and preppers that drink water directly from sources that haven’t been treated for disinfection and thus are likely to bear waterborne diseases.
In North America, a portable water filter should remove all bacteria and protozoa. This can easily be achieved by applying ultrafiltration or using a ceramic filter element. Viruses are usually not a problem. However, this could change when you’re visiting other regions of the world.
What types of portable water filters are out there?
What you should pay attention to when buying is low weight and compactness. You want a portable water filter that packs small and travels light. Also, durability and ease of maintenance in the field are critical.
Distillation is hands down the most effective way to purify water – purify, not filter. It’s fair to say that properly distilled water is the cleanest water one can get.
In the process, water is heated to its boiling point and vaporizes. As it rises, it leaves almost all contaminants in the boiling chamber behind and enters a cooling coil (condenser) where it cools down and condenses back into liquid. Finally, the purified water is collected in a separate container.
Why does the water get separated? Because most contaminants have a higher boiling point. Only some volatile substances condense at lower temperatures. This is why it’s important to have an additional charcoal post-filter stage. Furthermore, some distillers feature a built-in fan to discharge undesired gases.
What we also recommend you focus on when shopping for a water distiller is materials used. You want a water distiller with a boiling chamber made from food-grade stainless steel. Plastic or aluminum may result in even more contaminants leaching into the water. What’s more, the water should not get in contact with any plastic parts on its way to the (glass!) carafe to rule out recontamination.
Distillation works with different heat sources, from campfire to stove, but conventional water distillers use a boiling plate which runs on electricity. A full distillation cycle (1 gallon) takes around 4-5 hours using up to 3 kWh. At 12 cents per kWh, that’s 36 cents per gallon. Not too bad when you compare that to the cost of bottled water.
Just like water distillers, water softeners don’t filter water, they purify it. Speaking of purification can be misleading, though, since water softeners only remove hardness minerals, mainly calcium and some magnesium.
FYI: Water hardness does not pose a health threat. As a result, the EPA pays no attention to it. Which does not mean water softeners don’t have a right to exist. In fact, when dealing with overly hard water they are the only real treatment option. But what is hard water?
The USGS classifies water as “soft“, “moderately hard“, “hard” or “very hard” depending on how much calcium carbonate it contains. Concentrations are measured in ppm, mg/L, or grains per gallon (gpg). 1 gpg equals 17.118 ppm.
Soft water is between 0 to 60 ppm calcium carbonate, moderately hard water between 61 and 120 ppm. 121 to 180 ppm hardness is considered hard water. And very hard water is everything above.
You can measure calcium levels using a hardness test kits or having your water tested in a lab. Water Quality Reports also list that information.
In the end, the hardness has to be “bad enough” to justify the relatively high costs involved in acquiring and operating a water softener. This is where potential damage to your plumbing system and appliances coupled with increased energy bills make the investment worthwhile from a financial standpoint.
The Minnesota Department of Health recommends households classified as “hard” or “very hard” to consider buying a water softener to ensure that appliances run well. Hardness levels between 80 and 100 ppm provide a good balance between corrosion and incrustation.
We don’t want to say too much more about water softening at this point. For further reading, you’ll find many articles on BOS covering these topics and more:
Home water treatment is not only about water filtration or purification. There is water heating, there is water cooling, water storing, and so much more. We will try to cover every single topic as time proceeds. As soon as we’ve conquered a new area you will find it listed here:
As we said in the beginning, we hope this guide was a helpful introduction to home water treatment, giving you a summary of what you can expect to find on our website.
Finally, if you like what we do please spread the word and recommend BOS to your friends, family members and colleagues. We count on you and appreciate your support!
The BOS Team