Reverse Osmosis Maintenance Checklist

Reverse Osmosis systems are a great idea for a health conscious individual. They keep your water clean tasting and (for the most part) pure. So staying on top of your RO (reverse osmosis) system is vital if you want it to remain effective for you and your family.

One of the main reasons you should have a checklist in place for your system, is because with regular use, over time your filters, membranes and systems will eventually begin to get stuffy, kind’ve like my nose right now (I’m allergic to cats, and have been fostering four precious little kittens).

When maintaining your Reverse Osmosis system you should follow these steps:

  1. Ensure the water is off by first closing the shutoff valve, also make sure that any water line heading to your ice maker or refrigerator is shut off.
  2. Remove all water leftover in your RO system by simply opening up your RO faucet.
  3. Once all water has been drained out, bring your faucet back to it’s closed position.
  4. Wash your own hands, and be sure your working area is clean.
  5. Remove membrane from system.
  6. Remove pre-filters from their housing (sediment & carbon).
  7. Adding unscented bleach, or sanitizer to the pre-filter.
  8. You will then need to screw all of the housing that contained your pre-filters and membrane back in place.
  9. Turn the system back on by turning the valve.
  10. Check for leaks.
  11. Let it fill back up completely (might take a few minutes).
  12. Shut the valve off, and drain the system again by opening up the RO faucet.
  13. Do this a couple of times.
  14. Wash your membrane separately.
  15. Place your new filters in housing.
  16. Place your membrane back in housing.
  17. Turn your system back on.
  18. Check for leaks.

What is Reverse Osmosis?

Osmosis is a naturally occurring phenomenon, which involves weaker water particles (or less concentrated) to be attracted towards stronger ones (more concentrated) such as ions, through a semi-permeable membrane.

An example in nature would be if a red blood cell was placed into fresh water. The red blood cell’s cell membrane is semi-permeable and contains a higher concentration of ions than the water, so the water will move into the red blood cell by the process of osmosis. Eventually though, the cell would burst because it is more pressure than it could sustain, and would not be able to reach equilibrium.

Reverse Osmosis is, as the name implies the reversal of this process. Pressure is needed to be applied so that water can be pushed in the opposite direction at a faster rate than osmosis naturally moves in.

Your water pressure moves the smaller water molecules through a man made membrane towards your faucet, while simultaneously rejecting larger ones. The process allows for the removal of ions (salts), impurities like bacteria, virus’s and contaminants for the purpose of cleaner and purer drinking water.

Some different forms of contaminants are listed below:

  • Salmonella
  • Campylobacter
  • Rotavirus
  • Hepatitis A
  • Chloride
  • Copper
  • Chromium
  • Flouride
  • Potassium
  • Giardia

How The R.O System Works

You’ll note that your RO system has 3 canisters attached to it; the previously mentioned carbon/sediment filters and membrane are housed in these.

The first canister is designed for the purpose of removing the largest contaminants that will come into your system along with helping to reduce chlorine (which will be found normally in your municipal water supply). The placement of this filter helps keep the membrane protected.

The second canister houses your systems membrane, and arguably the most important. Usually this membrane will be made of a TFC (thin film composite) which is a synthetic plastic, that will allow the water molecules to pass through, and as previously mentioned, other larger particles will be rejected.

The last canister is sort of a back up so to speak. This filter takes care of any particle that just happens pass through the first two canisters.

Once the water has passed through the 3 canisters, it will then pass through a final ‘in-line’ filter, which will act almost as a polishing for the water to make certain you’re not getting any funky odors or unfavorable tastes.

How To Tell When To Change Your Filter

A key part of the maintenance of your system is to have an idea of when you will need to give it a wash, as well as ultimately knowing when is the best time to head out to your local home improvement store and pick up some replacement filters.

But how can you be sure? A good idea is to have checklist of some sort, one you can either keep under your sink next to your RO system, or in an organizer along with some other key reminder dates you may have, this could be a physical paper note book or even done digitally. Attached below is a printable PDF checklist that I created to help you keep on top of your maintenance.

Using the checklist, simply add in today’s date under “year 1” for whenever you purchased your RO system, and then check off the column when you replace a filter and add any additional comments you may have for that time.

One of the most tell tale signs that a filter needs to be changed, is if when you are using your faucet and you happen to notice a rotten egg odor. This may not be overly pungent, so get your nose in there! This is caused by bacterial growth, and if it is getting through your system, it isn’t doing it’s job properly.

Your water should also be visibly clear. If you notice your water starting to turn murky or cloudy, this could mean that particles such as silt, algae, manganese are getting through and in rare cases even methane gas.

Another great way to test if your filter needs to be changed is if you notice a drop in your water pressure over time, now this may be a little tough to notice initially especially if you use your faucet everyday, but as build up occurs inside of the filters, the pressure will keep dropping.

R.O Storage Tank

The storage tank for the reverse osmosis system is the reserve of water that has gone completely through the stages of filtration and needs a place to be stored. Your tank will have an inlet to allow water to flow into the tank, an outlet to allow the water to flow into your faucet and a pressure valve, which will allow you to re-pressurize your system.

Your tank has something called a bladder stored on this inside of it, that is made from a material called butyl. Don’t worry though, water does not at any point come in contact with the metal from the tank itself, only the butyl and the spout from which the water exits, which will be made of either a hard plastic or stainless steel.

When you buy your system, the tank will come pre-pressurized for you and that will normally sit at around 7-10 psi (pounds per square inch). The purpose of the this bladder is to allow for water to be pushed out through your faucet upon opening the handle.

A typical tank will give you a life span of around 5 years all the way up to 7 if well maintained. They will come in different sizes based on which system you decide to go with, and will likely only give you about half the amount of water for your designated tank size. For example, if you have a 4 gallon tank, you will only get around 2 gallons of usable water (which is more than enough for regular use), while the other half of the tank will be consumed by the inflated bladder.

Reasons a tank won’t preform

Ok, so let’s just say it hasn’t quite reached the 5 year mark from the time you bought your system and you notice that whenever you open the faucet, a quick burst of water comes out and then dies down to a mere dribble.

What can cause your RO faucet to lose pressure? There may be a hole in your tanks bladder. Lift up the tank to gauge how heavy it is, if the tank feels full of water, but not doing it’s job, it could be because the bladder was pierced, causing water to fill up the bladder and lose it’s pressure.

In this case, your best bet will be to go out and purchase another tank, and thankfully they are all interchangeable, meaning you won’t have to specifically look for the same make and model as the one you had before.

*There is a shutoff valve on your tank, usually made as a blue handle on the top of the unit. This valve will allow for you to isolate the tank from the rest of the water supply, allowing you to work on, maintain or replace the tank without having to shut off the main water supply for your house, or drain the whole system.

Before you head out to the store though, there may not actually be anything wrong with the tank. Just like the tire of your car or bike, over time your bladder will begin to deflate too. As mentioned before, the psi of the tank should be sitting around 7-10 psi, if it’s has dropped below that, your tank will not effectively be able to distribute water to you.

Re-pressurizing your tank

I recommend using this pressure gauge from Amazon, for testing the pressure in your tank, the gauge reads lower than 15 psi and can give you a more accurate read out as opposed to regular gauges.

Then simply with the use of a hand bicycle pump you will be able to get the tank back up to where it needs to be. Having too much pressure won’t cause water to flow out at a faster rate, but will in turn just leave less room, for less water.

  1. Shut off the supply to the RO tank
  2. Drain the water via turning on the faucet
  3. Lift the tank to see if water might still be inside
  4. Find the air valve on the tank – this is where you will hook up your compressor or bike pump
  5. While keeping the faucet open to allow excess water to be pushed out, pump the air into the tanks bladder
  6. Remove pump connection and use pressure gauge to ensure the psi is at 7-10 psi
  7. Turn valve slowly back on and check for leaks
  8. Turn faucet back on and enjoy

Your tank will also have an automatic shut off system in place. Once the tank reaches about two thirds the pressure of water coming into your house, it will automatically shut itself off. Example, if you have 60 psi coming into your house from the street, your tank will be able to hold maximum 40 psi before it decides to cut out.

*Note – If you are have little to no experience, you should always be consulting a licensed professional such as a plumber when installing or repairing your system. There is potential for leaks and flooding.

TDS – What is it?

TDS or total dissolved solids is the concentration in water of dissolved organic (salts) or inorganic matter. Some inorganic matter includes:

  • Chlorides
  • Magnesium
  • Sulfates
  • Potassium
  • Sodium

This matter ends up in your water stream for a variety of different reasons, such as salts that are used to de-ice roads can find there way into your water stream, as well as mineral spring water which will flow through regions where the rocks have high salt concentration to them. Other minerals such as calcium and magnesium show up simply because it is in the ground.

High concentrations of TDS is perfectly ok from a health perspective, and some people seek out drinks that have the higher mineral count. Alternatively though, a really low concentration can actually leave your water tasting flat, which is generally undesirable to a lot of people.

TDS meter

A simple, cost effective tool you can pick up to help you read the level of TDS in your drinking water is a TDS meter (link to Amazon), they cost around 12 dollars, and compact enough to fit away into a drawer.

A meter will also help provide you with information about when your membrane needs to be changed or when your system needs to be cleaned by showing you the amount of matter that has been rejected.

You can test this by going to a water supply that is not hooked up to a reverse osmosis system and checking the TDS using the tool, and then going over to the water source that has the RO system and testing it. If the rate of rejection is above 80%, the system is still doing it’s job, however if it dips below, it might be time to start looking into replacing the membrane.

Over time a membrane will begin to deteriorate, and it is recommended that it be replaced every two years. A meter can help to visually show you that this deterioration is taking place.

R.O System For Hard Water

A really really really big thing to consider if you have or want to buy an RO system is whether or not you have hard water in your house. Although the system is designed for rejecting things such as calcium and magnesium (which makes up hard water), it may not even be worth getting if the level is too high.

If you are replacing your filters more than the recommended once per year, and your membrane more than once every two years, this could be the root of it.

Hard water sticks to virtually everything and can cause scaling in the membrane. This scaling can lead to the membranes deterioration and render it useless.

A good way to tell if you have hard water is if you notice white spots on and around your faucet. Here are some other ways you can tell:

  • Dry skin – After you take a shower or wash your hands, you notice throughout the day your skin is dryer than it should be and itchy
  • Spots on dishes – You may notice when you clean your dishes that, once they are done drying on the dish rack, they will still have spots on them
  • Soap scum – When you look at your bath tub or curtains, the soap that inevitably gets washed off your body while leave a filmy white soap scum residue.

In my other blog post I wrote about another simple and fun way you can determine whether or not you have hard water so go check it out!

The solution to this may be investing in a water softener. The basics of what a water softener is, is that using a tank full of salt, hard water will pass through, and replace calcium and magnesium ions with sodium ones.

Sodium ions, unlike calcium and magnesium won’t interfere with soaps and detergents, and will help keep a balanced charge, leaving you with soft, harmless water.

Although you have the initial upfront cost of buying and installing a water softener, it will be worth it in the long run when you aren’t maintaining your RO system more than you have to.

If you don’t have hard water in the first place, consider yourself lucky.

As always, if you are unsure about your plumbing skills it is always best to contact your local plumber before starting any project. They will be able to help you best with the logistics of setting up the water tank under your sink, hooking it up and getting the proper connections where needed.


Tyler Takacs

My name is Tyler, I live in Ontario Canada and enjoy learning about common plumbing issues in the household. I have spent just over three years in the trades as a plumbers apprentice, but am now onto a less physical job. I still enjoy studying and learning about my own house's plumbing as well as finding ways to help others with their issues.

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