My question is:

In a water system, should water filtration come before or after the water softener? Edit: or even before the pressure tank?

At my cottage, we have a shallow well with an above ground jet pump. The "water system" is housed in an external pump house (basically a shed). The current flow is as follows:

well --> pump (pressure switch is on the pump) --> pressure tank --> water filters --> softener --> heater --> cottage

Water is pumped out of the well by the pump, then next is the water pressure tank, followed by three water filters (two for rust - different particle sizes, and the third is a "smell and taste" filter). Next is the water softener, then the water-heater inlet (where hot and cold splits) and then into the cottage from there.

It has been this way for three years, and no issues, but recently a plumber mentioned he would always have water flowing into the softener first and THEN through the rain fresh filters (opposite to what I currently have). I asked why and he couldn't articulate it other than it was what he had always done/was taught.

Based on the above components, is my current flow correct or are they in an improper order?

NOTE: we have incredibly rusty water... so rusty that without filters and softener, it would completely clog faucet aerators and shower heads after a few months. The pump is unhooked and drained before each winter, and every year it is seized from rust by the time I go to hook it up in the spring.

A few photos to give you an idea of what the water filters are:

enter image description here enter image description here

  • 1
    I would want my filters just as you do to keep dirt and small gravel out of the valves in the water softener. At minimum a particulate filter prior to the softener.
    – Ed Beal
    Apr 13, 2016 at 13:28
  • That was my thinking, I just wanted to make sure I wasn't missing something.
    – GWR
    Apr 13, 2016 at 13:37
  • My next question to that plumber would have been "do you cut the end off of a ham before putting it in the oven too?" As for the question, I can only imagine that which should come first depends 100% on the type of filtration/softener as well as whats in the water that you are removing. For example, if your filters are removing sediment and your softener valves are susceptible to sediment, then you should put the filters first. On the other hand, if your softener doesn't care about sediment, then it might make sense to put the filters last so you need to replace them less frequently.
    – kinar
    Apr 13, 2016 at 13:48
  • Yes, they are sediment filters... and I am going to assume "yes" for whether or not my "softener valves are susceptible to sediment"
    – GWR
    Apr 13, 2016 at 14:28
  • Are the filters of differing particle size, or "why do you have three of them in line?" - BTW, "rainfresh" is presumably a brand, not a type of filter - I'd call those cartridge filters, as a generic term, and since different types of cartridges can be put in them, mention what each one is using as a filter medium, or what it claims to filter out.
    – Ecnerwal
    May 6, 2017 at 16:18

1 Answer 1


I'd prefilter (based on your other question calling this "ridiculously rusty water") ahead of your replaceable cartridge filters with a cleanable/dumpable screen filter (a vortex with a permanent screen in the middle and a catch chamber and dump valve on the bottom) between the pump and the pressure tank. That type of filter works best with fast flow.

In fact, I do on my own system. Put a bucket under the valve and it removes what's caught in the chamber and blows the screen clear (since the pressure tank is on the "clean" side of it.)

The cartridge filters will be better on the upstream side of the pressure tank (where they are now) since faster flow does not help them work better.

As for the plumber, sounds like "future plumbing work guaranteed" to me. So the plumber might like it that way - having fought a water softener with valves that got funky in a "rusty water house" I'm not in favor of dumping rusty water into one unfiltered.

Edit - if you WANT to rearrange your filters you could make some small argument for putting the activated carbon (taste and odor) after the softener, but it's a small argument and probably not worth the hassle. You might want to take off the "watering gardens" water before it and the softener, though.

This is the type of filter I use - "spin-down" or "vortex" or "sediment trapper" with a sediment trap below the actual filter screen. water enters and is spun around the outside at high speed, then drawn through the screen - a fair bit of the junk slides down the walls where it's thrown & falls into the trap and thus is not clogging the screen.

I use the 200 mesh (finest) stainless steel element, as I'm dubious about the longevity of polyester screen elements, which go finer. And I very specifically put it between the pump and pressure tank, which is not where the manufacturer suggests, but it makes the best engineering sense (since having the tank upstream means that dumping the sediment trap automatically backwashes the filter, & it does not have to be opened in normal circumstances.) If the water shed is not dark you might want to give it a box or a black bag over it to keep it from growing algae. Look occasionally and dump what it's caught.

Spin down/sediment trapper filter

  • This is great. Thanks for the advice. Can you point me toward a "cleanable screen filter" you are referring to? Perhaps a link to one I could look at to start my research?
    – GWR
    May 7, 2017 at 11:02
  • Use search terms and you should be able to find them - I'm not wanting to A: make this an off-topic shopping question B: act like a spammer. I'm not affiliated other than as a normal customer and user of this product and there may well be other similar products from other companies available.
    – Ecnerwal
    May 7, 2017 at 13:54
  • Could it be put before the pump?
    – GWR
    May 7, 2017 at 19:27
  • The answer you already got to that question is accurate (I upvoted it, aamof) diy.stackexchange.com/q/114146/18078 - not a good plan. Nor needed - centrifugal pumps do not have tight clearances and can pump grit with little consequence. Next time the pump dies I would get a 2-wire stainless-steel submersible, rather than sticking with a jet pump in this day and age.
    – Ecnerwal
    May 7, 2017 at 21:18
  • I like this answer, but am confused each time you use 'upstream'. The word means 'closer to the source=well' -- you seem to mean the opposite.
    – amI
    Sep 21, 2018 at 16:31

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