Gravity Flow Water Filter

Hi Everybody, Frank here.

Hope everybody is having a wonderful day. Here in southeastern Oklahoma the weather is in the middle 80’s – middle 60’s. If you use your imagination, you can forget that just a few days ago it was 98 degrees with a corresponding humidity. Okay, so much for the weather.

Today we’re going to talk about water filtration. Like guns, radios and cars, there is no perfect water filter, but I’d like to share with you the type of system that we have used for about 20 years. We use a gravity flow filtration device. There are a few different models to choose from, some are plastic, some are stainless steel, and you can also make your own out of a couple of five gallon buckets. Probably the most popular brand is Berkey. They make numerous models and sizes, and they appear to make a quality product. But, Fern and I years ago, went with the Katdyn line of gravity flow filters. At the time, I really can’t tell you why we chose plastic over metal. I know the plastic has worked well for us, and when we lived in Alaska, it worked particularly well when moving from one location to another. You can pack all the parts together inside of itself. I love our United States Postal System, and I really do, but sometimes things can get banged around in the mail. So, we just stayed with the Katadyn Gravidyn, which is plastic.

Okay, the pieces. You have an upper chamber and a lower chamber. The lower chamber has one part, the spigot. The upper chamber is where you pour the water initially, it flows through the filters into the lower chamber, thus completing the gravity flow cycle.

Some of these type filters have holes pre-drilled for two, three or four candle type filters. We use one filter and we fill our top container once every two or three days. It’s about 2 gallons. That would take care of most families of four to six people, if you filled it more often.

But, if you want, you can add two of the candle type filters, or three, but you would need to have a very large family to justify this. The more candles, the more water it will filter, and if you’re the immediate gratification type, then you can have your filtered water much faster.

Like I said, we use one filter, and we fill it every two to three days. It takes eight to ten hours for the water to filter from the top to the bottom, so you could theoretically fill it up two to three times a day. But, in doing so, you have to make sure you drain the filtered water out of the bottom. Otherwise you will have an unscheduled mopping. So, if we get enough water for two people filling it every two days with one filter, then if you filled it twice a day, everyday, you would have enough water for about eight people with one filter. Not to mention if you filled it three times a day. So, if you use two or three filters, you can have a lot of filtered water for a lot of people if you work it.

The cleaner the water you put in to be filtered, the longer your filters will last. I guess you could go out and scoop up muddy water and pour into your nice, pretty, clean top reservoir, but in a short period of time, you’re

going to ruin your filter and clog it up. If you’re in this type of environment, there are ways to pre-filter water. There are lots of ways to do this. You can put water in a barrel and let it sit, and the heavy particulates will settle. Then you can either scoop or siphon it off of the top and have much cleaner water. If you choose, you can filter it through a t-shirt or a pair of pantyhose. You say, “Why would you do this? Isn’t this a gravity flow water filter?” Yes, it is, but it’s intended purpose is to filter microscopic type bacteria, so you need to have the water that you’re going to filter down to a very clean level. Okay, so don’t be pouring muddy water into your filter just to prove it will do it. Because if this is what you’re using to prevent intestinal parasites or diarrhea, then you might want to give thought to putting in pre-filtered water.

The manuals indicate replacing these filters every six months, and there are instructions for how to wash them if they get a little bit dirty. We take ours apart every month or two and give it a good scrubbing. All of the plastic parts you can wash with regular liquid soap and water. The filters themselves can only be washed in warm water, no soap. A word of caution. You should always follow the manufacturers advice, when to replace the filter. We do use ours significantly past the six month date. I can’t address the other manufacturers replacement recommendations, because I have never used their products. 

There are some companies that just sell a filter. You take a five gallon bucket; put it on top of another five gallon bucket with a lid in between the two; drill matching holes into the bottom of the top bucket and into the lid of the bottom one; install your filters between the bottom of the top reservoir and the top of the bottom reservoir; drill a hole near the bottom of the bottom reservoir; install a spigot; and you’re good to go. 

We have used this type of water filter for around 20 years now. We used it all over Alaska where the treated water is sometimes of a questionable nature. Now, we use it to filter our rural water, which is also of a questionable nature. There is some question as to whether or not it will filter fluoride. There is also some question whether it will filter chlorine.

But you don’t need to filter chlorine. Either before or after you filter your water, let it sit in an open pitcher on your counter top, and the vast majority of the chlorine will dissipate into the air. I don’t understand why we continue, or ever started, to put fluoride into our drinking water. If you need fluoride treatment for your teeth, the brush your teeth twice a year with a fluoride toothpaste. Fluoride is horrible for older people. You need to do your own research on fluoride. Good luck on finding a commercially made toothpaste that doesn’t have fluoride. It’s in your toothpaste and it’s in most, but not all, municipal water systems. I can find no good use for fluoride. It is terrible for babies to consume, and it does horrible things to the elderly folks bodies. So much for that.

If you would like to remove microscopic particles from your drinking water, then I can recommend the Katadyn Gravidyn gravity flow filter. Hope this helps.

We’ll talk more later. Frank

P.S. My father was the acting chemist for Dallas County Park Cities Water Control and Improvement District, No. 2 for about 20 years. He is my source of data for flouride. He was adamantly opposed to the introduction of fluoride to the water systems. Shortly thereafter, he left the water treatment business and opened a restaurant. Just thought you might want to know.

10 thoughts on “Gravity Flow Water Filter

  1. Well, Fiona, you might need to just lighten up a bit. I have stories and stories of things that I have broken. When we were building a house years ago, I broke two brand new toilet stools while we were installing them. They just don't make porcelain like they used to.Frank

  2. This is a great post…we had not heard of this brand of filter.It looks simple and functional. Frank…one note…you cannot fix fence with me, I always crank the fence stretcher one more time…you know to get it perfectly tight! I cannot count the time I have heard the horrible twang as the wire breaks!

  3. Joshua, we use a little green Scotch pad to gently scrub the exterior of the filter. No soap. No additives whatsoever. Just warm water and a very gentle scrub. Then, if you don't get through the exterior porous type material, then your filter should still be serviceable. Don't drop it. It will break. Thanks for reading.Frank

  4. Thank you for the excellent commentary. We have also stocked up on quite a few of the filters. Now this is not a recommended practice, but if you will take a cotton sock, put it over your filter and put a rubber band on the bottom to hold the sock, some of your heavy minerals and other particulates will adhere to the sock first. You might try this technique. You see, I have a tendency to break things, and I have broken the nipple off of more than one filter when getting it too tight. You know, just a little bit more, one more turn, maybe? You don't have to remove the filter to put the sock over it. Just food for thought. Thank you for sharing. We're all in this together.Frank

  5. Just Me, as you know, you still need to boil spring water. Never know what little microbes might be lurking around. I would do the research and find out what water system works best for you. In our bug out bags, we have a battery operated gizmo called a SteriPEN. It operates off of a couple of rechargeable AA batteries. Check it out also. Thank you for reading.Frank

  6. Leigh, thank you for the reading. You're right, Katadyn isn't near as well known as Berkey.That is a cool picture on the header, isn't it? Thanks again for the comment and thanks for reading.I've also really been enjoying your pig articles.Frank

  7. The instructions that came with our berkey claim we can rejuvenate our filters by slicing the outside layer off with a vegetable peeler. I'm not convinced, but admittedly I haven't spent much time thinking about it, or testing it. The filter elements are awfully expensive, so I certainly I'm not supposed to be buying a new one every six months.

  8. Frank – excellent info as always! like Leigh above, we went with Berkey because i knew of Berkeys from the military. and i had not heard of katadyn when we were researching as well. when we first started prepping, we put money aside every month to add to our preps but also put money aside for buying more filters. after several years, we now have a lifetime supply of Berkey charcoal filters. we also bought 2 Berkey towers but last year my husband did the 2-five gallon buckets thing and we use 3 filters at a time due to the fact that our well water is very mineral-ly! we have found that by cleaning the filters every month, like you do, that we can get a good 6-7 yrs out of a filter. we love our Berkey filters but i have read many prepper sites that use Katadyns, and i have heard nothing but good about them.excellent post, Frank. please keep them coming!

  9. Really good information here! Not everyone – (me!) – knows even the basics of this topic. You've managed to \”boil it down\” to an understandable explanation here – complete with pictures. Time for me to \”spring\” for one of these babies, I guess. (Did you catch my water puns there?)Just Me

  10. Frank, what a great post. We have a Berkey, but I'd never heard of the Katadyn when we were researching. Tell Fern I love the new blog header photo!

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