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Clean a Reverse Osmosis Membrane at Home

How to Clean a Reverse Osmosis Membrane at Home

Reverse Osmosis Membrane Cleaning

Even the best reverse osmosis system has to be well maintained to function properly. Only when a system is in good condition can it process water efficiently and remove its contaminants. One essential maintenance step is cleaning a system’s ro membrane, which is a reasonable alternative to cost-intensive replacements.

Membrane cleaning requires knowledge of when and how you have to clean and what chemicals you have to use. The right cleaner depends on the type of fouling/scaling the membrane has been exposed to.

In this blog post we are going to shed some light on those aspects and provide step-by-step instructions on how to clean your ro membrane at home.

When to Clean

Since it’s difficult to clean overly fouled reverse osmosis membranes and to prevent irreversible damage, it is crucial to stay on a strict schedule and clean them at an early stage of fouling.

day planner scheduleThe easiest way to find out when to clean is by monitoring water pressure before and after the system. If the differential pressure increases by more than 10%, it’s time to get active. The need for higher feed pressure to maintain water flow and decrease of flux are also clear indicators that your membrane needs to be looked after.

Of course cleaning frequency varies between different models from different manufacturers and also depends on the level of water contamination these are subjected to, but on average every ro membrane should be cleaned once about every 3 to 12 months. It is also helpful to take a look at the instructions provided or to get in touch with the manufacturer for further information.

How to Clean

The following instructions created by lead you through the process of cleaning a ro membrane. Please be aware that the necessary steps to clean a membrane without causing any damage to the system might vary from one manufacturer to another. This is especially the case for countertop systems (find more information on countertop systems here:

  1. Turn off the system’s water supply.
  2. Turn off any water line going to a refrigerator or icemaker.
  3. Drain all water from the filter system and storage tank by opening the system’s water faucet.
  4. Close the faucet once all water has run out.
  5. Disconnect the membrane housing from the system and open it.
    • The best way to open up the housing is by using a strap wrench.
    • If you are also cleaning your filters, make sure to disconnect the membrane first, because cleaners such as bleach will destroy the membrane.
  6. Drain all water out of the housing and take the membrane out of it.
  7. Clean the membrane using a chemical cleaner suggested by the manufacturer or a reverse osmosis chemical supplier and follow the given instructions precisely. Take into account dosage, temperature, pH-values and contact time guidelines.
    • As stated above, depending on the type of fouling/scaling the membrane has been exposed to, you need to use different cleaners. Common types are:
      • Calcium carbonate scale
      • Metal oxides deposits
      • Silica scale
      • Inorganic and organic colloidal deposits
      • (Natural) organic material like mold and fungi
  8. A Note on Chemical Membrane Cleaners

    You have the choice between generic cleaners and more expensive labels. Expensive cleaners are oftentimes easier to use and customer support is more reliable.

    This becomes even more important when you have to use a number of different cleaners in the right sequence one after another. Improper use might make the degree of membrane contamination worse. Here is an example sequence:

    1. Acid Cleaner
    2. Flush
    3. Alkaline Cleaner
    4. Flush
    5. Sanitizer
    6. Flush
  9. Remember to also clean the membrane housing by using a bottle brush and some regular dish washer detergent and bleach mixed with water.
  10. Dispose of all cleaning chemicals adequately.
  11. Rinse the membrane and the housing thoroughly before putting them back together.
  12. Re-install the housing back onto the system.
  13. Turn on the system’s cold water supply and check for leakages.
  14. Flush the system before refilling your water tank to remove chemical residues.
    • Water quality might take a few hours to get back where it used to be especially after pH cleanings.

Time to get Started

Start lineYou now have all the necessary information you need to clean the membrane of your reverse osmosis water filter system. You should be able to figure out how and when to clean and what chemicals to use in which sequence.

Remember: It is essential to follow the manufacturer’s specifications precisely to not cause any damage to your system. If you are unsure about your next step, seek professional assistance to avoid mistakes.

gloves in toolbox

How to Make a RO Water Filter at Home

Make your own Reverse Osmosis Water Filter

You would like to have access to filtered reverse osmosis water in your house. You would like to install a filtration system, but at the same time you want to save money and therefore not buy an expensive all-in-one solution. So you are thinking about making your own reverse osmosis water filter at home. Let’s stop here for a moment.

The problem with doing this from scratch is that you need pre-treatment filters, a pump to increase water pressure (if psi in your house is too low), a reverse osmosis membrane, a filter housing, piping, adapters, valves and more.

Reverse osmosis membranes cost between $60 to $100 depending on their capacity. In regards to pre-filters, there are a few options to choose from. Granulated Activated Charcoal (GAC) is the most common type of filter. It removes unwanted particles such as lead and other contaminants. Solid or powdered carbon blocks are the other type of basic filters that remove water contaminants usually to a higher degree as well as chlorine and fluoride. Carbon filters cost about $25.

Adding the costs for housings, valves and water lines, it’s unlikely that you do any better than the mass-marketed filtration units in terms of money that you would have to invest. In addition to that, finding a semipermeable ro membrane suited to your needs, that fits in a housing that is working under pressure and does not cause any water leakages is pretty difficult.

Well, that doesn’t look very promising. So what are the available alternatives?

Buy a Filter System and Connect It yourself

One possible alternative to building your own reverse osmosis system from scratch is to buy a regular 3 to 5-stage filtration unit that doesn’t come with valves, water lines etc. and install it for example under your kitchen sink using component parts you bought at your local hardware store, such as:

  • T-valve
  • Water lines (¼″)
  • Quick connect with shut-off function
  • Water tank

How to Connect the System

In order to connect the system:

  1. Attach the t-valve to the cold water line of your kitchen sink. By using a t-valve you will still be able to turn on the cold water at your sink.
  2. Tee off the ¼″ water line to your filter system. Add the quick connect between the system and the valve to allow water to be shut off, when system is not in use.
  3. Once the water went through the whole system, you have 2 outputs. Let the wastewater flow into your kitchen sink. Collect the filtered water in a tank, if you want to store it. Make sure that the tank is BPA-free and food-safe.

The following video is a great demonstration of how to do the setup.

Hardly Any Advantages

To save money it’s always a great idea to make things yourself instead of buying them. Unfortunately, it’s not easy to build a well-functioning reverse osmosis water filter system that is not leaking any water and comes cheaper than a commercial ro unit that can be bought in stores or online. What’s more is the extra time and effort you have to invest have not even been taken into account yet.

We recommend you to read some of our reverse osmosis reviews. Maybe you can find a filter unit that suits your needs and fits your budget. We also created a list of the best countertop ro systems here, that usually are a lot cheaper and don’t need to be installed, which is a time saver.

Portable Water Filter

You might be interested in another type of homemade water filter that is cheap, easy to build and portable. However, this self-made filter does not utilize a reverse osmosis process. You are going to need:
water bottle with lid

  • Large plastic water bottle with lid
  • Plastic straw
  • Cotton batting
  • Activated charcoal granules
  • Large and fine grain gravel
  • Large and fine grain sand
  • Coffee filter
  • Jar

Proceed as follows:

  1. Cut off the bottom of the water bottle.
  2. Create a hole in the lid large enough to fit in the plastic straw halfway.
  3. Place the bottle with the straw onto the jar upside down.
  4. Place the cotton batting at the bottom of bottle as the lining for your water filter.
  5. Place a first layer of activated charcoal granules on top of the cotton batting followed by a layer of fine grain sand. Next comes a layer of large grain sand, then a layer of fine grain gravel followed by a layer of large grain gravel.
  6. Alternate the layers until the bottle is filled up.
  7. Place the coffee filter on top.

coffee filterIn order to clean your water, pour it through the coffee filter. Contaminants will be absorbed as it moves down the bottle to the straw. The filtered water will than trickle through the straw and into the jar.

Obviously, you can’t process a great amount of water using this filter and every once in a while, you need to replace the cotton batting, charcoal granules, gravel and sand. Still, it’s a cheap and easy way to get access to filtered drinking water, if your budget does not allow for a more pricy reverse osmosis system.