Replacement Water Filter Cartridge

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Well-known member
Aug 27, 2010
San Antonio, Tx
I am getting ready to replace the water filter cartridge in the RV for the first time.  It is a single cartridge system.  Looking at CW and online at the RVWaterFilterStore, there are all types of filters available.  What type of cartridge do you folks recommend?  Type of material?  Microns? Flow rate? #months use?  What is most important?  Thanks
The answer has to be a personal choice. I use a washable & reusable filter that basically just removes sand and coarse crud. It has a high flow rate and never needs replacement - I just hose it off and put it back in. Fine for our needs, but we aren't picky about the tap water. Others feel they need a high degree of filtration, maybe to remove chlorine or microbes of various breeds. That sort of low micron filter is readily available but comes at a severe water flow penalty and the only way around it is to parallel more filters - or forget the filters and go to a reverse osmosis system. The RV Water Filter Store has a page that explains the tradeoffs rather well.

Personally, I choose a higher flow rate (4-5 gals/min) over higher purity.  2gpm makes for an inadequate shower in my book.

Your needs may differ.
A lot depends on where you are. Where Gary lives, tap water is palatable. Here in AZ it isn't and you really need good filtration. The RV Water Filter Store put together a package for us that works great in making AZ water taste good and deleting "stuff" in the water. I have a sediment and a KDF filter that work great.
Great info above. The nice thing about many filter housings is that they will accept a variety of filters. Most often we use a high GPM filter as Gary suggests for his area. We do keep an extra and a lower flow, high filtration cartridge on-board in case we run into a place with less desirable water.

The whole house, high flow filter is our choice along with a higher filtration, single faucet (and icemaker) filter for purity and taste.

If you have to change filters just prior to winterizing, just take it out and keep the cartridge in the freezer during the winter. Thaw and re-use in the spring. Bacteria will not form in the frozen cartridge.
Good point, Bernie. For the two summers we spent in Moses Lake, WA, the water was really alkaline. We kept the same filter set-up but drank bottled water. Wasn't a problem in the shower and sink, except it didn't soap up as well.  I also had to clean the filter weekly. Folks that used disposable cartridges were buying them every couple of weeks.
Thanks to everyone for this input on this topic.  Based on your comments, I emailed Rick at the  Rick provided a lot of useful information and recommended the possibility of a dual canister system.  Since this is our first MH and we are not full-time, I think I will try just the single canister approach first.  I plan to use try their F1pb cartridge.  If that doesn't work, I may go with a dual setup as Rick outlined.

Much of the info Rick provided is available on the website.  Since this may be a topic of interest to others, I have included my two emails and Rick's responses below to help folks get this info without having to search.  I have used this company twice now and been very impressed with their responsiveness and help.

First email.  Rick.  I have a 2005 Allegro Bay MH with a single canister water filter.  I bought this used and am looking to replace the current water filter for the first time.  Looking at various RV forums, some folks say they used just a sediment filter because they want to maintain good water flow.  Others say you must have a good KDF filter for water quality regardless of water flow.  Given that I have a single canister system, what filter would you recommend as a replacement?  I was looking at the PR-5, the CBC-KDF-10, and the F1Pb (CFB-PB10).  Could you please tell me the pros and cons of each and how the water flow for each would compare?  Thanks,  John

Response.  John, There are many opinions and it is not to say that any of them are wrong.  If you do sediment only, then the water's taste and odor will not be improved.  Things like chlorine or sulfur gas can be pretty extreme and may not be appreciated by many RVers.  If you would rather not shower or brush your teeth in such conditions, never mind if you drink it, then you would need a carbon filter to do the job.  If you don't care about that, then a sediment cartridge would be valuable, and the PR-5 is good for going green and saving some money over the typical throwaway types.  If you want a carbon filter, then you would serve yourself best by using a combination sediment/carbon type.  Solid block, such as the CBC-KDF, will do all that, but is limited in the depth capacity for catching sediment.  It would be better to have a second canister with a sediment only cartridge ahead of it, so that it would last longer.  However, the F-series cartridges, such as the F1pb, F1, or F5, are very good as combination cartridges because they flow better than solid block carbon filters by about 25%, have increased depth capacity to catch more sediment before plugging up, and are naturally resistant to stagnation because of the fiber material they are made from.  The F1 and F1pb would be rated for cysts (giardia and cryptosporidium), the most common living organisms you will encounter as an RVer.  They will also cover chemicals and pesticides, and the F1pb does lead and heavy metals.  The F5 does not have the cyst or LHM ratings.  It will flow a bit faster, but not by much.  These are industrial filters and very popular in manufacturing due to the high performance they offer.  They have much of what most RVers would like to get out of a single canister setup.  You can check the links below to find the filters you mentioned and many others.  Flow rates and more info is there to compare each.  KDF is a zinc and copper alloy that has a lot of good features for an RV filter, too.  But the flow rate is much less than the F-series, and a bit less than most solid carbon blocks.  It will not catch sediment when it is the KDF-GAC type, although that has a pound of KDF and will really provide the performance KDF is known for.  The KDF impregnated in the CBC-KDF is good for keeping the cartridge from stagnating in storage, but that is about it.  As you can see, I have the most enthusiasm for the F-series because I have found over the years that customers are very happy with them, overall, and reorder them routinely.  Naturally, if I can make you happy with a filter, you are more likely to come back to us for replacements and that is good business.  However, we carry all this variety because there is always the customer that has something specific they like or are used to, and I wish to be able to fill the need, whatever it may be.  Each filter has some advantage over another, generally, but some like the F-series, are more of an all around feature filter with a reasonable cost that more of the customers will appreciate.  I hope this helps you zero in a little more as to what you may wish to try.

Second email.  Thanks for the quick response and all of the good info.  Another question.  If I changed to a two canister system, what would you recommend I use for the filters?  Would the flow rate for a two canister be the same/higher/lower than a once canister.  What would such a setup cost me?  FYI, I bought a Watts adjustable regulator from you and keep my pressure at 55-60.

Second response.  John, Since you have a filter now that covers you when hooked up to shore water and coming from the pump, or at least that is the most common way manufacturers hook them up, then the one thing you are missing is a sediment filter to fill your tank.  This keeps dirt that will settle in the bottom of your tank from happening.  So I would say that to create the equivalent of a double canister, you would just get one single housing with hose fittings and use a sediment cartridge in it.  You could mount this in the bay if there is room, or just use it portably and lay it in the bay or under the RV in the shade.  It will not need to stand upright.  This filter will also protect whatever you may choose as the new replacement for your carbon filter.  A SED5 or SED1 cartridge would be good for that and they are $5.95 and $7.95 per pair.  The canister housing in opaque white is $29.95 with brass hose fittings.  Now if for some reason you are asking about a dual canister system, which would create the concept of a triple canister system, then you might use one of each micron size sediment filter and then the carbon.  Having three housings for filters gives you a little advantage in special conditions where a filter could be useful that you may not need to use all the time.  For instance, a cartridge for iron removal that is not present all the time, but helpful when it is.  Most do not get that prepared in advance, but if you are more of a prepper type person, there could be an advantage at some point.  The more cartridges that are banked together, the more reduced the flow will become.  It is not an extreme reduction, but a little.  Basically, the most restrictive cartridge you may choose sets the bar and then additional cartridges used will slow it down a bit because of the pressure drop that occurs over every filter.  So the first one in line gets full pressure from your regulator, and then the second one has to operate off of a slight pressure reduction caused by the first, and so on.  A little extra pressure setting on the regulator will add a bit to that original pressure available, if the park has it.

"Second response.  John, Since you have a filter now that covers you when hooked up to shore water and coming from the pump, or at least that is the most common way manufacturers hook them up, then the one thing you are missing is a sediment filter to fill your tank.  This keeps dirt that will settle in the bottom of your tank from happening."

I would check to see if your present filter is for city water use only. The most recent three motorhomes I owned all had the diverter to fill the tank AFTER the filter. That way all water that enters the motorhome, either for immediate use or filling the tank gets filtered. This is not to say that yours or even most do this, but it is worth checking before purchasing another filter.
A few years ago I connected two filter housings together and connected hose prior to going into the MH. The problem I encountered was some RV parks have lower water pressure. Sometimes I lacked water pressure to get a good flow. In todays world many of the MHs have their own filter housing already mounted. I use that one and if we have high enough pressure I add an additional housing outside the MH.

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