How to Install a 7-Stage Reverse Osmosis System
Written by: Gene Fitzgerald // Last Updated: Sep 13, 2023
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Installing a 7-stage reverse osmosis system might sound intimidating, but it is just as easy as installing a 3 or 4-stage; it is just a bit bigger and takes a bit longer!
But everything is always easier with clear instructions, so we made you this step-by-step!
Contents
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Key Takeaways
To install your 7-stage reverse osmosis system:
- RO Faucet Installation: Drill a hole, insert the faucet, and secure it with a wrench.
- Drain Saddle Installation: Position above the dishwasher and garbage disposal, create ¼” opening in the drain line and attach clamps.
- Feed Valve Installation: Turn off the cold water supply, disconnect the tubing, install the new valve, and reconnect the tubing.
- Storage Tank Installation: Place within 10 feet of the faucet, apply Teflon tape on the threaded port and attach the tank valve.
- RO Module Mounting and Tubing Connection: Connect the module with color-coded tubing and ensure the tubes are fully inserted.
- Water Lines Installation: Attach supply line to feed water valve, connect lines to tank valve, drain saddle, and RO faucet.
- Filters and Membranes Installation: Insert pre-filters, RO membrane, and post-filters into housings and tighten securely.
- System Activation: Open the feed water valve and RO faucet, check for leaks, flush the system, and fill the storage tank.
How to Install a 7-Stage Reverse Osmosis System
Please note: For this installation guide, let’s say your 7-stage RO system has a sediment pre-filter, two carbon pre-filters, the RO membrane, a UV post-filtration step, a carbon post-filter, and a remineralization filter.
Here is how to install a 7-stage reverse osmosis system step by step:
1. Install the RO Faucet
If your sink doesn’t have a hole, you’ll need to drill a new one in the sink or countertop. Make sure there’s a flat area for the faucet. Depending on the material, use a special drill bit to prevent scratching.
For a stainless steel sink, mark the spot and gently grind away enough material. Go slow and use a drop of oil. If you need a larger hole, start with a pilot hole.
Insert the faucet, secure it from underneath, and attach the water line fitting. Tighten it with a wrench.
2. Install the Drain Saddle
To keep your RO system free from clogs and contamination, place the saddle/adapter higher than the dishwasher discharge and garbage disposal. Make sure it is at least 6 inches higher than the p-trap.
Create a ¼” opening in the top or side of the drain line, avoiding drilling at the bottom. Securely attach the drain clamps using bolts, aligning the clamp hole with the pipe’s hole. Be careful not to tighten too much.
3. Install the Feed Valve
To begin, turn off the cold water supply. Next, release the pressure in the water line by opening the respective outlet. Then, disconnect the tubing from the cold water valve and securely install the new feed valve using a wrench for tightening.
Remember to close the feed valve at this point. Connect the cold water tubing to the new valve, and if necessary, use an adapter for this step. Finally, turn the water supply back on, and you’re all set to go!
4. Install the Storage Tank
For water pressure, place the water storage tank within 10 feet of the faucet. Be cautious, as the filled tank can weigh more than 25 pounds!
Prior to installation, wrap several layers of Teflon tape around the threaded port at the top. Attach the tank valve or connector securely by hand-tightening. In some systems, the storage tank can be positioned horizontally without affecting filtration performance, making it convenient when space is limited.
5. Mount the RO Module and Connect with Tubing
You can connect the module with the right tubing easily, as it is often color-coded. Make sure to push the tubes in as far as they can go, and then check the connection by gently trying to pull them back.
6. Install the Water Lines
Start by attaching the supply line securely to the feed water valve. Then, connect the other end to the feed port of the RO module. Adjust the line length if necessary to avoid any kinks. Next, connect one line to both the tank valve and the outlet port of the filter system. For the next line, connect it to the drain saddle and the flow restrictor of the RO module. Ensure that the line is cut in a way that allows water to flow without forming loops. Finally, connect the last line to the quick connect fitting of the RO faucet and the post-filter outlet port.
7. Install All Filters and Membranes
To set up the different pre-filters, post-filters, and the RO membrane in their respective housings, follow these steps:
- Start with the sediment and carbon pre-filters. Unscrew the filter housings, insert the filters, and securely screw the housings back on, making sure that all O-rings are correctly positioned. Use the filter wrench to carefully tighten them.
- For installing the RO membrane, remove the housing cap and gently push the cylinder into the socket until it is fully seated. Put the cap back on, ensuring a snug fit for any O-rings.
- Lastly, install the UV, carbon, and remineralization post-filters. Unscrew the filter housings, slide the filters in, and then screw the housings back on. Use the filter wrench to tighten them securely.
8. Turn the System On!
To start, open the feed water valve and the RO faucet. Keep the storage tank valve closed. You might hear gurgling noises as air exits the system. Check all connections for leaks.
After about 15 minutes, water will start dribbling out of the dispenser. Don’t worry if it looks slightly darker initially. This occurs as carbon fibers are flushed out. When the dribble begins, close the faucet and open the storage tank valve for a few hours to fill the tank.
Once the tank is full, you won’t hear water running down the drain anymore. Now, open the drinking water faucet to flush the entire unit. When the water flow turns into a dribble, it means the storage tank is empty. Close the faucet and let the tank refill.
Perform a second flush by opening the faucet. Some manufacturers suggest flushing a new system 2-3 times before using it. Once you finish the flushing process, the setup is complete.
Components of a 7-Stage RO System
Having a solid understanding of all the components in your 7-stage RO system will also help with installation.
System Module
A singular component made from plastic, it serves as the crucial link between all the different parts. This includes elements such as the pre and post-filters, a specific RO faucet, and a containment unit for water storage.
Pre-Filters
In a 7-stage RO system, pre-filters are typically composed of a sediment pre-filter designed to clear out debris and two carbon filters that are effective in removing chlorine and other chemical substances. These pre-filters play a protective role, guarding the delicate reverse osmosis membrane from potential damage and blockage.
RO Membrane
The main component responsible for water purification is the reverse osmosis membrane. Its core role is to filter out any contaminants that might have managed to evade the pre-filters. The RO system achieves this by using a semi-permeable membrane and applying pressure to separate the impurities and dissolved solids from the water. The clean water is then transferred through the membrane into the storage tank, leaving behind the impurities, which are then discarded with the wastewater.
Post-Filters
Once the water departs the storage tank, it goes through the final stages of filtration. In this scenario, these stages involve a UV purifier, a carbon post-filter and a remineralization filter. These filters work to kill any pathogens that may be in the water, remove any remaining off-tastes or smells from the water in the storage tank, and reintroduce essential minerals back into the water.
Bladder Tank
This pressurized container is used to store the water that has undergone reverse osmosis, ensuring a continuous supply of filtered water whenever it is needed.
Faucet
RO systems are equipped with a designated faucet. This ensures an optimal flow rate and prevents any potential mix-up with your regular tap water.
Further Reading:
Drain Saddle and Drain Line
These elements guide and transport the wastewater generated during the filtration process away from the system for elimination. This wastewater is laden with contaminants that have been filtered out of the water through reverse osmosis.
Feed Water Valve
This valve serves as a bridge between the water supply of your kitchen faucet and the reverse osmosis system.
ASO Valve
When the storage tank is fully filled, the automatic shut-off valve interrupts the water filtration operation. It only restarts when the tank’s water level drops again.
Check Valve
This valve aims to prevent reverse water flow towards the RO membrane, which could potentially cause harm.
Flow Restrictor
This component regulates the water pressure exerted on the reverse osmosis membrane, ensuring it maintains the perfect pressure for effective filtration.
Tubing
Your system will feature several tubes that interconnect all the different components.
Fittings/Connectors
Your system will be equipped with connectors and fittings, often color-coded to simplify the installation process.
If you have any questions about 7-stage reverse osmosis system installation please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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