RO System Correct Functioning

  • The RO System Correct Functioning is about the optimal usage of your water.
  • The prevention of excessive water wastage from the RO system.
  • People install their RO systems themselves to save money or the DIY that thinks they know all and can do anything better than the professional person.

RO System Correct Functioning and the appearance of your RO water filter when changed:

RO System Correct Functioning

RO System Correct Functioning

  • You will notice that the water filter have a layer of brown sludge around it.
  • This sludge is from the sewerage treatment plant.
  • It is organic matter and decomposed faeces.
  • In this brown sludge you will find different types of parasites, live organisms and bacteria that you would normally find in the sewerage treatment plant.
  • The brown sludge is a sign to us that a large volume of water passed through the water filter or the RO system.
  • Is it not normal that the water filters is covered with this brown sludge?
  • Yes we find it with every new client of us that had their RO system serviced by other service people.

What is the difference between water filters?

RO System Correct Functioning

RO System Correct Functioning

First the quality water filters that’s been used.

Secondly, the service procedures the service people followed.

Thirdly, the testing and calibration of the RO system.

Fourthly, the quality RO Membrane that’s been used.

You have mentioned four things, can it be that important?

Yes it is!  When we service our RO systems after a year our last sediment filter is still white or have an off white appearance. Yes we do not get brown sludge filled water filters like the other service people get.

It is all about quality and the correct service procedures.

A RO system that is not been installed correctly or calibrated can cost you the client thousands every year.

Brown sludge layer on water filter:

Large volume of water passed through the water filter. Filters most of the time is of low quality. System water inlet water pressure is too high. A part of the RO system is damaged or sticky. Waste water flow all the time. Water wastage can be in the thousands of liters.

Test to see if your RO system is functioning correct:

Close tap on top of storage tank.

Open the faucet and let the water low.

Is it dripping? (a)

Is the water flow about 30 mm? (b)

Is the water flow more than 50 mm? (c)

(a) The membrane is clogged up.

  • Do this test after you have serviced and changed the water filters.
  • Remember to flush the membrane.
  • If the water still drips then the RO membrane is clogged.
  • The RO inlet water pressure may be too low, lower than 280 kPa.
  • Measure the water flow for a minute or 5 minutes.
  • Get the amount that it flows in a minute.
  • Let’s say it is 75 ml per minute.
  • Now measure the waste water flow for a minute.
  • Let’s say it is 250 ml per minute.
  • To be frank, this is a waste of water.
  • For every 750 ml purified RO water that you get, you waste 2.5 litre of water.
  • If you use 5 litre purified water per day you have wasted 16.650 ml of waste water.
  • To get that 5 litre of purified water you have used 21.650 ml.
  • If you use every day 5 litre purified water you have used 649,500 ml of water just to have 150 litre of purified water.
  • Let’s look to a year: 1,825 ,000 ml purified water for a year.
  • 6,077,250 ml of waste water and in total you have used 7,902,250 ml during that year.
  • It is 7,902 litres for that year.  that is acceptable for the people in the RO market.
  • Not for us.


  • If the water flow for about 30 mm from the opening of the faucet and then starts to make drops it means the RO Membrane is fine and the water inlet pressure seems fine.
  • It is a sign that the RO system is working correct.


  • This is disaster in progress.
  • Inlet water pressure is too high.
  • Part of the system is damaged or sticky.
  • Water flows pass the RO membrane into the storage tank.
  • Water in the storage tank could be contaminated.
  • O ring damaged.
  • Pipes could be wrongly installed.
  • RO membrane is damaged.
  • This is not a good sign.
  • If I see the water flow this way it is a big red flag for me.

Our RO water filters after a year was used:

Our RO water filters still have a white or off white colour after it were used for a year. We place our sediment water filter last to see if our other water filters is working. If I look to our sediment water filter it seems if the filter is still new.

RO water filters and RO Membrane lifespan:

  • If you use high quality water filters then the membrane will last longer.
  • The purified water is of high quality and water wastage is controlled.