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How to change Reverse Osmosis Filters

This tutorial explains how to change the filters inside a standard Reverse Osmosis Water Filter system. This is the type of system most people will be familiar with as it is the traditional design and the most widely available model of RO system.

5 Stage Reverse Osmosis Water Filter


Firstly lets looks at what filters we have in the above system. Each pod contains a 10″ long water filter cartridge, from left to right there will usually be the following internal filters: FEED WATER COMES IN >  POD 1 CONTAINS SEDIMENT FILTER  >  POD 2 CONTAINS CARBON (GAC) or CARBON BLOCK FILTER > POD 3 CONTAINS CARBON BLOCK FILTER.   From here the water will then travel through the Reverse Osmosis Membrane, and then either straight into the tank or through the Post Carbon Filter / Alkaline or Mineral filter cartridge (if your system has one).

These Filters will look similar to this in order:

10 inch Sediment Filter

10 inch Sediment Filter

Granular Activated Carbon Filter

Carbon GAC filter

Carbon Block water filter

Carbon Block water filter















From here the water will then pass through the Reverse Osmosis Membrane (which is inside a filter housing horizontal on top of the other 3 pods), and then finally through the post carbon filter:

Reverse Osmosis Membrane

post carbon water filter

post carbon reverse osmosis water filter








Once you have identified the above filters you can use the following steps to change them. Note that the reverse osmosis membrane would not normally be changed unless necessary (such as if it is years old or the TDS is increasing / it has high usage)


RO Pre-Filter Change Instructions

  1. Turn off incoming water to system (either at the mains clamp or the inline valve on the mains pipe to the system if you have one)
  2. Turn off Tank Valve
  3. Turn on the water filter tap / water filter lever on your 3 Way Tap to release pressure, then turn off the tap
    1.  Unplug power for pump if you have a pumped unit
    2. Disconnect all pipes to the system and lay the system flat on the sink draining board. (you may wish to use a towel when disconnecting the pipes as water can drip out the system – mostly from the waste water pipe) to disconnect pipes if you are using push-fittings you simple pinch the little collect that sticks out of the push fittings down against the fitting itself, then pull the pipe out. If your system has screw type fittings (jaco fittings) then just unscrew these and pull the pipe out.
    3. Loosen the three big pods with a 10” filter housing spanner, and remove by hand. (if you don’t have one of these spanners you can try a adjustable rubber grip but these pods can really seize on)
  4. Identify filter type and Remove + Replace filters one at a time with the same filter type (the order will be Incoming Flow > Sediment Filter > Carbon GAC > Carbon Block
  5. Then tighten the pods back onto the system making sure the internal rubber gasket is still in place in each pod
  6. Only use the spanner to tighten the pods on a little bit so that they are on firmly, do not over tighten or they may be very difficult to unscrew upon next filter change.
  7. At this point it is recommended to flush these pre filters. To do this connect the mains water feed pipe to the system, and disconnect the pipe from where it comes out of the last big pod (the carbon block filter) and flush water through these new filters until it runs clear – this just helps prolong the life of your reverse osmosis membrane.
How to change the Reverse Osmosis Membrane (if required)
  1. The Reverse Osmosis Membrane sits inside a filter housing laying horizontal across the top of the system and is usually clipped into place.
  2. Simply disconnect the pipe from the end of the housing with the screw cap, and unscrew the cap (you may need a Reverse Osmosis Housing Spanner for this)
  3. Pull out the old filter (with pliers if needed) and slot in the new filter
  4. Screw the cap back on and push the pipe back in
Changing the Post Filter – Post carbon / Alkaline Filter / Mineral Filter
  1. The final filter (post carbon/Alkaliser/mineraliser cartridge) will have a Tee connector on one end, connecting to the system and the tank, and an inline connector on the other end, which goes straight to the tap (usually however this configuration can differ, best thing to do is replace with a new filter like for like where your old one was).
  2. Simply unscrew the fittings / or release them if push fittings, and put in your new post filter – making sure you follow the flow direction arrows so they match
  3. Put system back into place and reconnect up
  4. Flow through the system several gallons of water to flush out the new filters



  • Make sure all push fittings are in completely and when pulled on stay in place, you should feel them slide into place when done correctly.
  • Make sure pipe is smooth at the end when reconnecting the system, if not cut the end off so that it is smooth – replace section of pipe if necessary otherwise it may leak.
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October 7, 2011 at 9:39 am
1 comment »
  • October 12, 2011 at 12:15 amTaylor Akau

    Howdy blogger, thank you for providing this article.. I found it first-class.

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