How Long Does it Take for a Big Berkey to Filter Water?

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Can't wait for pure water?! Patience, young grasshopper. 🦗 Great things take time and Berkey water is no exception. The flow rate for a Big Berkey is about one gallon per hour with two Black Filters in the upper chamber. Since the Big Berkey holds 2.25 gallons it will take about two hours and fifteen minutes for the entire upper chamber to be filtered through to the bottom chamber. Of course, there are some variances and it may filter faster or slower based on a couple of different scenarios.

Faster does not necessarily equal better. We want it to take its time working its way through the tortuous path of the Black Filters--that's what helps trap and block some of the contaminants. However, if you do want to speed it up some, you can add more filters to the upper chamber. For example, the Big Berkey can hold a maximum of four filters, which increases the flow rate to two gallons per hour (one hour and eight minutes to filter the 2.25 gallons).

Flow Rate for other Berkey Systems

One reason your system may be filtering slower is the addition of Fluoride Filters. because it's one more step that the H20 has to go through it decreases the flow rate. The dense media in the Fluoride Filters prevents fluoride and arsenic from getting into your drinking water. 

Another possibility for the sluggish flow rate is only partially filling up the upper chamber. Make sure to pour water all the way to the top every time! (Make sure the bottom chamber is empty to prevent an overfill spill) By only filling the upper chamber up partially two detrimental things happen. One, the filters are working un-evenly. The bottom portion of the filters has to work harder and more often than the top portion. And two, the gravitational pull is less. The full weight of 2.25 gallons (or whatever the maximum capacity is of your system) helps to "push" the water down and through the filters. Always fill up your Berkey all the way! 

After a while, sediment can build up on the filters--which is good! That means that gunk isn't in your water. If it seems like your water filter is going slower than normal try removing the filters and giving them a good scrubbing. We recommend using a Scotch Brite pad (Have you seen our Maintenance Kit?) under running water to revitalize the Black Filters. If that still doesn't work, review our troubleshooting page. Sometimes re-priming the filters helps alleviate slow flow. 

Air bubbles may also cause lethargic filtering. That can be resolved by adjusting the upper chamber and/or adding an anti-airlock clip.  It attaches to the lower chamber to prevent a suction effect, slowing down filtering speed. 

Each filter is special, some drip and some create a stream. Either is fine, just be sure to stay in tune with your system so that you notice any changes, which may indicate an issue. If it's filtering too fast it may be time to do a Red Dye Test and replace the Black Filters, and if it's filtering too fast it may be time to clean them. Get to know your Berkey and what's the normal speed for it to filter. Each one is a little different. 

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