A reverse osmosis system is a water purification system used widely in homes as well as wide scale water purification plants.
The reverse osmosis process is based on principle of osmosis but in this case the osmotic pressure is reversed and pressure is applied to push water through a semi-permeable membrane.
You need to do regular maintenace on your reverse osmosis system in order to keep the membrane and the stages performing to their fullest capacity.
The semi permeable membrane separates out dissolved particles in the water and only pure water is allowed to pass through the membrane.
The reverse osmosis process is a well established water purification process and there are several water purification companies that have adopted this process. Small home based water purification systems are also being developed on the same standards.
Reverse Osmosis System Maintenance Schedule
Here’s a quick guide to know when to maintain your RO system:
- Replacing filter stages: once to twice a year
- Cleaning the system: once a year
- Checking storage tank pressure: once a year
- Replacing RO member: once every two to three years
A simple reverse osmosis system mainly consists of three stages: A pre-filter, the Osmotic Membrane, and a post filter. Advanced osmosis systems also have four or five stages for improved water purification, but the additional stages still fit somewhere in the pre or post filters.
The pre-filtering stage usually consists of a filter cartridge to separate out sand, silt, and other residual particles. This stage is important so as to protect the Reverse Osmosis (RO) Membrane from damage caused by these particles, as they’re quite large in size.
A carbon filter is also used after this stage to remove pesticides and most important chlorine from the water. Chlorine must be removed before water can be filtered through reverse osmosis as it can damage the delicate RO membrane. Both of these filter cartridges must be changed every 6-9 months.
If you don’t change these cartridges your RO membrane might get damaged and water purification will also be affected; you might notice a specific taste and odor in water.
Pre filters generally need to be changed much more often than post-filters, as post-filters receive mostly purified water.
Most reverse osmosis systems have one or two post filters. The first post filter is a carbon filter which further removes any smell or taste from the water, and makes it taste good enough to be drinkable.
Higher end reverse osmosis systems often have remineralizing or alkalizing stages which actually add beneficial minerals back into the water before dispensing it for use. This is often a wise option to go for as water with beneficial minerals is generally better than water with no minerals.
The remineralizing stage must be replaced once every 6 to 12 months, depending on how much you use the system.
If you don’t change your filter regularly, your water quality will be severly affected:
- Water will start tasting and smelling bad
- The output of your RO system will decrease
- More water will be wasted
- Dirty filters may encourage the growth of harmful bacteria
An important thing to note is not to use any old filter! Your RO system’s manufacturer most likely sells replacement filter stages, and it’s best to use filters from the same manufacturer. Otherwise you may run into compatibility issues.
If your system is very old and filters are no longer available, you may need to just get a new system.
Finally, it’s a good idea to stock up on some replacement filters when you first buy the system so you never end up scrambling to find filters at the last moment.
Reverse osmosis membrane maintenance
Next is the reverse osmosis stage, in which water is pushed at a pressure of 35 psi to pass through the membrane. The thinly perforated RO membrane will separate the solutes from the solvent and only pure solvent is allowed to pass through.
This RO membrane is the central part of an RO system and its maintenance and regular cleaning is of utmost important to get clean, purified and fresh water.
You can clean the membrane every 3-4 months to prevent clogging of pores. If cleaned properly, this membrane has a longer life span. However; it must be changed every 2-3 years.
How to clean an RO system
The best time to clean an RO system is whenever you open it to change your filters. This way you can kill two birds with one stone and not have to open the system multiple times.
To clean the system, follow these instructions:
- Turn off the water
- Depressurize the system by opening the nozzle and letting any water flow out
- Remove all the filters from their holders, and clean the insides of the housing with warm soapy water. Rinse with regular water until the soap has been removed
- If you want to sanitize one step further, add some bleach or Dettol(or any sanitizer) into the housing of stage 1. DO NOT REPLACE THE FILTERS YET!
- Close the entire system with the filters out, and turn on the water supply
- Open the faucet and let water start flowing out, and then close it, making sure to check for leaks
- Let the storage tank fill up. Let the sanitizer sit in the system for one to two hours
- Open the tap and flush out all the water
- Let the tank refill again and flush out all the water
- Let the tank refill a third time and flush out all the water
- Multiple flushings are important as you need to get all the bleach out!
- Repeat steps 1 and 2, and install the filters back in the housing
- Turn on the water and check for leaks
Checking RO storage tank pressure
Check the pressure of your storage tank once or twice a year. You can do so using a simple pressure gauge. It’s important to know the empty tank pressure, so you can compare that to a full tank’s pressure.
Read our in-depth guide to RO tank pressure here.
Here’s a quick summary:
- Replace all filters every 6-9 months or max 12 months.
- Replace RO membrane every 24-36 months.
- Sanitize the water tanks every year.
- Cleanse and re-assemble the plumbing pipes every 2 years.
- Replace and buy new parts when necessary.
- The pressure nozzle must also be checked at regular intervals.
If you don’t properly maintain your reverse osmosis system, the performance and quality of purification will greatly be affected; you might experience offensive taste and odor of water and low water pressure. Low water pressure is an evident sign that your filter and membrane life is running out.
If you properly maintain your RO system, it can last as long as 10-15 years. Remember, clean filters and membranes mean pure and healthy water.