Many people know that reverse osmosis produces quality filtered water, but what about systems like Berkey that use other filtration methods?
We’ll break down the main differences between Berkey filters and reverse osmosis systems, and help you decide which system is the best one for your home.
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Final Summary – Berkey vs Reverse Osmosis Filtration
Thanks to their long filter lifespans, ease of use, and cost-efficiency, we believe that Berkey filters are generally better than reverse osmosis systems – even though they don’t work on total dissolved solids (TDS).
These are the main things we looked at when making our decision on the best filtration style:
|Berkey Gravity Filtration||Reverse Osmosis Filtration|
|Contaminants Removed||200+||400+ and TDS|
|Filter Lifespan||4-7 years||1.5-2 years|
|Filtration Rate||84 gallons per day||75 gallons per day|
Berkey vs Reverse Osmosis Overview
Berkey is an established leader in the water filtration industry. They’ve been making excellent products since 1976 including in-line shower filters, but their main claim to fame is their countertop water filters.
Reverse osmosis (RO) systems, on the other hand, can be found as countertop filters but are most commonly seen as under-the-sink installations that are plumbed into the water line. There are a wide variety of brands that make RO products, and the quality of the system will vary with the quality of the manufacturer.
Berkey uses gravity filtration in all of their products. This means that as water is poured into the top holding chamber of the model, both gravity and the weight of that unfiltered water force the water through the filters below.
The Berkey gravity systems all use Black Berkey filters, which contain a proprietary blend of five different filtration media. These filters use activated carbon, ion exchange, and microfiltration technologies to purify the water as it’s forced down through them. At the bottom, clean water collects in the holding tank.
Activated carbon, also known as activated charcoal, filters water by adsorption. This means that as the contaminants in water pass over the activated carbon surface they become trapped – either by being unable to pass through the tiny pores in the carbon (microfiltration) or by becoming electrostatically trapped.
Ion exchange also works by adsorbing contaminants, but in a different fashion. Water passes over resin beads that contain anions, cations, or both. When a negatively charged particle encounters the anion resin, it becomes trapped and releases a benign anion back into the water in its place. When a positively charged particle encounters the cation resin, it becomes trapped and releases a benign cation back into the water.
Since gravity is providing the power to force the water through, there’s no electricity required for the Berkey countertop filters to function. There’s also no water used or wasted in the process, and no separate tank needed for storage afterwards.
Reverse osmosis, on the other hand, works in a different manner altogether. With a countertop system you would feed the water into the top of it just like the Berkey. But, as mentioned, with most RO systems they’re already hooked up to the water supply under your sink.
There’s two compartments in the RO filter that are separated by a semi-permeable membrane. This membrane generally has extremely small pores that allow water molecules to pass through but not the vast majority of contaminants.
In regular osmosis, water wants to flow to where the concentration of dissolved particles is highest. Reverse osmosis is achieved by using a pump to generate pressure to force water across the membrane, away from the dissolved contaminants.
The brine water is the contaminated water that is left behind from this process. The permeate is the fresh, filtered water, and it collects in a holding tank afterwards while the brine water is flushed away. The RO pump requires electricity to operate and the flushing process to remove the brine uses water. You can generally expect to use four gallons of water for this for every one gallon of water filtered.
Just as the Berkey uses a filter that combines multiple types of filtration, it’s rare to find a RO system that relies solely on reverse osmosis. Many will have sediment filters, activated carbon filters, or other stages to further purify the water.
Now that you know a bit more about each kind of filter and how they work, let’s see how they compare on key qualities like the number of contaminants they remove, the lifespan of their filters, and the filtration rate.
In order to compare apples-to-apples, we used our pick for the best under-sink RO system – the Waterdrop G3 – and compared it to the most popular Berkey model – the Big Berkey.
|Waterdrop G3||Big Berkey|
|Semi-Volatile Organic Chemicals||✓||✓|
|Inorganic Chemicals (Including Heavy Metals)||✓||✓|
|Total Dissolved Solids||✓||X|
|Microbial Cyst Reduction||✓||✓|
|Bacteria and Viruses||✓||✓|
Both the Big Berkey and the Waterdrop G3 RO system remove the same classes of contaminants, with one exception – RO also works on total dissolved solids (TDS). TDS are minerals that are dissolved in water like calcium and magnesium. In addition to making water more alkaline on the pH scale, TDS also determines how “hard” water is.
Hard water can lead to a host of issues for your home including scale buildup and shortening the lifespan of your appliances. When water softener systems remove TDS they replace them with a benign ion like sodium or potassium, but when RO systems remove TDS nothing else is put back in.
This can cause your water to become slightly acidic, and high levels of TDS can also significantly shorten the lifespan of your RO filters. For these reasons it’s still recommended that you use a true water softening system if you struggle with hard water.
As for the other contaminants, the difference is that the RO system removes more contaminants in each class and overall. In fact, the Waterdrop G3 removes 2x the number of contaminants as the Big Berkey.
Even though RO systems generally remove a wider variety of contaminants, the question remains – do you need that level of filtration power for your home?
You can actually get your water tested to find out exactly what contaminants are present in what amounts. This will let you see whether you have contaminants that are covered by Berkey’s filters, or if you have other contaminants that would require RO to remove.
You can see the full list of contaminants that Berkey’s filters remove here.
With a Berkey system, the filtration rate is 3.5 gallons per hour for 2-filter units. This means that over a 24 hour period, the system would be able to filter 84 gallons. The flow rate from the spigot is what you would expect as well from a dispenser-style product.
With a RO filter, you can expect it to put out anywhere from 20 to 400 gallons per day of water depending on the system and manufacturer. Many systems have around a 75 gallon per day rate. They often come with their own separate faucet that’s installed next to your sink faucet, and the flow rate is usually in the ballpark of 0.5 gallons per minute from that faucet.
Another thing to look at is how long the filter for each system is going to last. For the Black Berkey filters, each one has a 3,000 gallon capacity. While the exact amount of time that they last will depend on your water usage and the number of people in your household, you can expect a two-filter system to work for 4-7 years before needing to be replaced.
Reverse osmosis filters, on the other hand, often need to be replaced much sooner. The average RO membrane will last for 18-24 months before needing to be swapped out. This is partially to be expected, since under-sink units are using water for dishes and other things besides drinking. But even the AquaTru countertop RO filter only has a 1,200 gallon capacity.
Berkey and gravity filtration in general is the more cost-effective option when compared to reverse osmosis. The Big Berkey, for example, goes for $278 for the 2-filter model while the 4-filter model is $388. The replacement filters are $128 for a 2-pack, and there are no other costs associated with maintenance and operation.
In comparison, RO systems can run anywhere from $200 to $550 depending on the brand and the style. Taking the average at $375, you’re already starting at about $100 more than the 2-filter Berkey. You’ll need to replace the RO membranes much more frequently, which can run anywhere from $50 to $100, and there’s other costs to consider as well.
Since the pump requires electricity, you’ll have a small bump in your power usage. However, the most costly part of operation is all of the extra water that’s required to flush out the accumulated brine water. The good news is that if you can get a RO system with a higher level of efficiency, you’ll be able to cut down on some of the extra water costs.
Customer Reviews Comparison
The Big Berkey has a 4.7 out of 5 star rating on Amazon, with 1,651 reviews. 85% of those are 5-star, while only 4% are one star. Customers loved that no installation is needed and that they were able to stop spending money on bottled water.
On the other side of the coin, there are multiple complaints of a rubbery taste to the water that stems from the filters. Some customers also reported that the stainless steel housing starts to rust after some time, but Berkey does offer lifetime warranties on their products.
With reverse osmosis systems, customers have said that the installation and setup is more involved – though most brands make it easy enough to do that you don’t need a plumber. Customers likewise loved that they could cut back on bottled water, and they also loved that the TDS and hardness of their water was reduced. The main complaints with RO systems are the wasted water, which is an unfortunate inevitability, and the slower water flow rate.
Pros and Cons
Here is a summary of the main advantages and disadvantages associated with each system.
- 200+ contaminants removed
- Does not acidify water
- Lifetime warranty
- 84 gallons per day filtration rate
- 4-7 year filter lifespan
- No installation needed
- No water wasted or electricity needed
- More cost-efficient
- Not as many contaminants removed as RO
- Does not work well on TDS
- Some reports of rubbery taste
- Some reports of the filter housing rusting
- Countertop models only
Reverse Osmosis Pros
- 400+ contaminants removed
- Works on TDS
- Up to 400 gallons per day filtration rate
- Usually straightforward installation
- Variable warranty
- Both countertop and under-sink models available
Reverse Osmosis Cons
- Can acidify water
- Can reduce flow rate at the faucet
- Electricity required and waste water generated
- Shorter filter lifespans
- More expensive
We believe that you’re better off going with a Berkey filter than a RO system due to the lower cost, longer filter lifespan, and lack of installation needed. You can browse all of the filters that Berkey has to offer on their website, and find the model that will best suit your home’s needs.
If you have your water tested and it comes back with contaminants that the Berkey filters don’t work on, or if you would rather have purified water at your faucet, then by all means get a reverse osmosis system. They work exceptionally well at filtering water and there are a wide variety of brands and systems available for you to consider.
You can check out our recommendations for the best RO water systems, or you can read what other customers have to say about different products to find the one that will work best for you.