Your Guide to Installing a Reverse Osmosis Filter System

Clean and pure drinking water is essential for maintaining good health and well-being. Reverse osmosis (RO) is an advanced filtration method that can effectively remove a wide range of contaminants, including minerals, heavy metals, and microorganisms, from your tap water. It can also remove undesirable taste and odor from your water.

Here, we’ll walk you through the process of installing a reverse osmosis water filter system in your home.

Choose the installation location

Selecting the right location for installing your reverse osmosis water filter system and preparing the area for setup is crucial to its performance and convenience. Consider these factors and tips:

• Proximity to water source and drain: Choose a location that’s close to your cold water supply line and drain. This minimizes the length of tubing required and ensures efficient water flow and drainage. RO filtration systems typically work best when installed vertically on the side of the cabinet.
• Under-sink space availability: Check the space under your sink to make sure there’s enough room for the RO unit, storage tank, and any other components. Use a tape measure to measure the space under the sink and determine the exact dimensions of the RO unit and storage tank to get a proper fit. Consider leaving some extra space for ease of installation and maintenance.
• Accessibility for maintenance: Avoid placing the filtration system in a spot that’s difficult to reach or obstructed by other plumbing components so you have easy access for future maintenance and filter replacements.
• Clear out clutter and obstacles: Empty the cabinet under the sink and remove any items that might hinder the installation process. This provides a clean workspace and helps you work efficiently.

If you have a garbage disposal

• Install your RO system under the sink and away from the disposal. It’s important that the water flow bypasses the disposal completely to prevent damage.
• Place the RO drain saddle upstream and as far away as possible from the garbage disposal. If the drain connection is installed too close to the garbage disposal, the drain line could quickly get clogged and cause your new RO system to stop working prematurely.
• You can use a garbage disposal drain adapter to combine the RO drain line and the disposal line. This can help prevent interference and backflow.

Gather your materials and tools

Before you begin the installation process, double-check that you have all the necessary components and tools on hand to save time and frustration along the way.

Keep in mind the components may vary slightly based on the specific reverse osmosis water filter system you’ve chosen and most required parts should be included with the new unit from the manufacturer.

Materials

• Reverse osmosis (RO) water filter unit: Main component of the system that contains the filters and membrane.
• Pre-filter and post-filter cartridges: Remove larger particles and certain contaminants before water enters the RO membrane.
• RO membrane: Core element that filters out most contaminants, including minerals and impurities.
• Installation instructions: Included with the RO unit from the manufacturer.
• Storage tank: Holds the purified water for on-demand access.
• Dedicated faucet: Dispenses the purified water.
• Air gap: Allows for proper drainage of wastewater.
• Mounting bracket: Holds the RO unit securely under the sink.
• Fittings and connectors: Necessary for joining tubing and components.
• Teflon tape: Seals threaded connections to prevent leaks.
• Screws and anchors: Help secure the mounting bracket and other components.
• Drill and hole saw: Required for creating holes in the sink or countertop for the faucet installation.

Tools

• Adjustable wrenches for tightening fittings.
• Phillips and flat-head screwdrivers for various tasks.
• Drill and bits for creating holes for the faucet and mounting bracket.
• A tape measure to accurately measure distances for installation.
• Pipe cutter or scissors to cut tubing to the required lengths.
• A bucket or towels to catch any water during installation and testing.

How to install a reverse osmosis water filter system

1. Prepare the water source

Before you begin installing your reverse osmosis filter system, you’ll need to prepare the water source by shutting off the main water supply, identifying the cold water line, and installing the necessary valve or fitting. This is important for a steady and controlled water supply.

1. Locate the main water shut-off valve in your home.
2. Turn off the main water supply to prevent water flow while you work on the installation.
3. Find the cold water supply line under your sink. This line is usually identified by its blue color and is connected to the cold water faucet.
4. Follow the manufacturer’s instructions for installing the chosen valve or fitting.
5. Make sure the connection is secure and leak-free.

2. Mount the reverse osmosis unit

With the water source prepared, it’s time to mount the reverse osmosis water filter system securely under your sink for stability and ease of access.

1. Locate a suitable spot under the sink for mounting the RO unit. Make sure it’s easily accessible and doesn’t interfere with other plumbing or items stored under the sink.
2. Hold the mounting bracket against the chosen spot and mark the positions of the screw holes.
3. Use a drill to create pilot holes for the screws. Ensure the holes are aligned with the bracket’s holes.
4. Securely attach the mounting bracket to the cabinet using screws and anchors.
5. Carefully place the reverse osmosis unit onto the mounted bracket. Ensure it’s level and properly aligned with the bracket’s slots or hooks.
6. Secure the RO unit to the bracket according to the manufacturer’s instructions. This might involve sliding the unit onto hooks or locking it into place.
7. Double-check the alignment and stability of the RO unit. It should be securely attached to the bracket and not wobble.
8. Make sure there’s enough clearance around the unit for easy access during maintenance and filter replacements.

3. Connect the tubing and filters

Proper connections are essential to prevent leaks and ensure the system operates efficiently. Follow these steps to carefully connect the tubing and filters so water flows through the necessary stages of filtration:

1. Check the manufacturer’s instructions or labeling to correctly identify the purpose of each tubing. RO tubing often comes in different colors to indicate their purposes (e.g., red for hot water, blue for cold water, black for wastewater).
2. Connect the tubing to the pre-filter’s inlet and outlet ports. The inlet is usually connected to the cold water supply, while the outlet connects to the RO unit.
3. Attach the tubing to the post-filter’s inlet and outlet ports. The inlet is connected to the RO unit, while the outlet connects to the faucet.
4. Connect the RO membrane housing to the tubing, ensuring a secure fit.
5. Attach tubing to the storage tank’s outlet port and the wastewater port of the RO unit.
6. Locate an appropriate spot for the storage tank, which will typically be on the side of the cabinet.
7. Attach the tubing from the storage tank to the faucet’s inlet port.
8. Connect the waste water tubing following the manufacturer’s instructions for installation.

4. Install the faucet

The dedicated faucet is a key component of your reverse osmosis water filter system and provides easy access to your purified water. Here’s how to install it:

1. Choose a location on your sink or countertop for the dedicated faucet. It should be easily accessible and not obstruct other faucets or items.
2. Use a pencil to mark the center of the chosen location.
3. Measure the diameter of the faucet’s base or shank.
4. Using the marked center point, use a hole saw of the appropriate size to create a hole in the sink or countertop.
5. Follow the manufacturer’s guidelines for drilling the hole to the correct depth.
6. Insert the faucet shank through the hole from above the sink or countertop.
7. Underneath the sink, place the rubber washer and mounting hardware provided by the manufacturer.
8. Tighten the mounting hardware to secure the faucet in place. Avoid overtightening, as it could damage the sink or faucet.
9. Attach the tubing from the storage tank to the faucet’s inlet port.
10. Ensure the tubing is securely attached and doesn’t kink or bend excessively.

5. Install the drain

Installing the drain correctly helps prevent backflow and maintains good water quality. If it’s set up right, the drain will help:

• Prevent clogging
• Prevent back pressure
• Keep purified water from being contaminated
• Maintain compliance with plumbing codes that require air gaps or free-flowing drains
• Prevent damage to the RO membrane or pump
• Ensure that your RO system has a longer lifespan

Follow these steps to install the drain:

1. Locate the drainpipe under your sink.
2. Determine where the drain line from the RO system will exit. Common locations are the kitchen sink drain or a dedicated air gap on the countertop.
3. Follow the manufacturer’s instructions for installing an air gap if indicated as being required. An air gap is usually mounted 6-10 inches above the sink rim or counter near the faucet/drain board.
4. Cut the drain tubing to length if needed to reach the exit point without kinks or tight bends.
5. Check the tubing for a continuous downward slope from the RO system to the exit point. This allow for proper gravity draining.
6. Make sure the connections are secure and properly aligned.
7. Check for any leaks after connecting the wastewater tubing. You can do this by running water through the RO membrane and monitoring the drain connection point.
8. Adjust connections as needed until water drains smoothly without drips.

6. Install the auto shut-off valve

Auto shut-off valves are an important safety feature on reverse osmosis (RO) water filtration systems. They help safeguard the RO filter and home plumbing. They also:

• Prevent water waste by shutting off the incoming water supply if the RO membrane becomes blocked or clogged. This stops untreated water from passing through and being wasted down the drain.
• Protect the membrane by preventing excess pressure that could build up over time if the membrane gets blocked. This pressure can damage the membrane.
• Maintain safe plumbing by preventing a blocked membrane, which could cause a burst of back pressure that may damage plumbing connections or cause leaks.
• Provide alerts to homeowners about service or maintenance that might be needed, like replacing the membrane filter.
• Maintain energy efficiency and peace of mind by preventing the system from consuming energy and water if it’s not functioning correctly.
• Keep code compliance by preventing flooding or water damage from failures.

How to install the auto shut-off valve:

1. Identify the incoming water supply line before it reaches the RO system. You’ll install the valve here.
2. Turn off the water supply and release any pressure in the line.
3. Disconnect the line where you’ll install the valve. The valve will need threaded or compression fittings to match.
4. Determine the proper valve orientation for your setup. This is usually vertical with water flow going up through the valve base.
5. Apply plumber’s tape or paste to the threads if using threaded fittings to connect the valve.
6. Hand-tighten the valve into place between the two line ends. Do not overtighten.
7. Reconnect the line coming from the water source above the valve base.
8. Reconnect the line leading to the RO system below the valve body.

7. Perform final checks and testing

Before you start enjoying the benefits of your newly installed reverse osmosis filter system, it’s important to conduct final checks and testing to make sure everything is functioning as it should.

Follow these steps to confirm that your filtration system is ready to provide you with clean and purified drinking water:

1. Carefully inspect all connections, including tubing, filters, and fittings.
2. Make sure there are no visible leaks or drips. If you notice any leaks, address them as soon as possible by tightening connections or replacing faulty components.
3. Slowly open the main water supply valve.
4. Monitor the connections and tubing for any sudden leaks that might occur as the water pressure increases.
5. Once leak-free, test that the auto shut-off valve shuts off automatically if you obstruct the RO system outflow.
6. Open the dedicated faucet and let the water run for a few minutes.
7. Observe the flow of water and ensure it’s steady and consistent. If the flow is weak or irregular, there might be a blockage or improper connection that needs attention.
8. Let the system run for about 10–15 minutes to flush out any residual impurities from the filters and membranes.
9. This flushing process confirms that the water you’ll be using for drinking and cooking is clean and free from any initial contaminants.

Maintenance and troubleshooting tips

A well-maintained reverse osmosis system will serve you and your family for years to come. Taking care of your system and remaining prepared to address common problems is vital to ensure its continued efficiency and the quality of your drinking water.

Regular maintenance tips

• Follow the manufacturer’s recommendations for filter replacement intervals. This is typically every 6 to 12 months.
• Replace pre-filters, post-filters, and the RO membrane as needed to maintain the best filtration performance.
• Regularly clean and sanitize the storage tank according to manufacturer recommendations.
• Keep the area under the sink clean and dry to prevent moisture-related issues.
• If you’ll be away from home for an extended period, consider shutting off the filtration system to conserve water and extend filter life.

Troubleshooting

• If your system produces less water than expected, it could be due to a clogged filter, improper water pressure, or a malfunctioning component.
• If the water flow from the dedicated faucet is slow, it could indicate a clogged filter or membrane. Check and replace filters if necessary.
• If you notice leaks, check all the connections. Tighten fittings if needed. If leaks persist, consider replacing faulty components.
• If the purified water has an unusual taste or odor, it might indicate that the filters need replacement or the system requires cleaning.

More information

Thanks for reading! We hope this guide has helped you successfully navigate the installation process of your reverse osmosis filter system as you take a significant step toward enjoying clean and purified drinking water right from your tap.

If you have any other appliance repair needs or projects, don’t hesitate to contact us at 1-877-477-7278 and visit AppliancePartsPros.com. There, you can find parts with your model number, chat with a pro, and find more guides on our DIY blog.

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