This guide details how to properly install a reverse osmosis (RO) water filtration system. It contains easy, step-by-step instructions for every stage of the process, including planning the installation location, installing the RO system, and verifying the unit works as expected.
Preparing for the Installation
Before installing your RO system, complete the tasks below for a safe, smooth, and efficient installation.
Gather the necessary tools and materials.
Begin by gathering all the tools required for the installation. These items generally include:
- Adjustable wrench
- Channel-lock pliers
- Power drill with appropriately sized drill bits (see owner’s guide)
- Level
- Safety glasses
- Tape measure
- Phillips and flathead screwdrivers
- Utility knife or tube cutter
- Bucket or rags
- Teflon tape
- Marker and pencil
- Adapter tee
Also, check that you have received all the items listed on the parts sheet for your specific system. Have these components within reach during the installation.
Plan the installation location.
Next, map out the locations for the RO assembly and storage tank. Start by reorganizing or removing any items stored inside your sink cabinet to make room for the unit. Afterward, measure the space beneath the sink to ensure the system can fit. The RO system should not obstruct any plumbing or other objects. Additionally, there should be enough room to reach the housing and change the filters as needed.
Prepare the RO faucet hole.
Finally, you’ll need to prepare a spot to install the RO faucet. If your sink has an existing sink sprayer or soap dispenser hole, you can use it for the faucet installation. If not, you’ll need to drill a hole in the sink top or the countertop next to the sink.
If drilling is required, choose a suitable drilling point on the sink deck or countertop. Ensure the opening won’t interfere with anything beneath the sink, and there is sufficient room beneath the sink to make the necessary connections. Next, use a marker to mark the exact drilling location. Drill a pilot hole, then re-drill the same hole to the size specified in the manual.
Important: Make sure to use the correct type of drill bit and follow the proper procedure for drilling into the specific surface material. If your countertop is made of granite, quartz, or another material that is prone to splitting, it is generally recommended to have a certified professional drill the faucet hole.
How to Install a Reverse Osmosis Water Filtration System
Please read and follow the instructions carefully to successfully install and set up your RO system.
Turn off the cold water supply.
Before anything else, locate the cold water valve under the sink and turn it clockwise to shut off the water supply. Open the cold faucet to relieve pressure in the line and drain any remaining water. If water continues to flow, close the main shutoff valve to cut the water supply to the entire house. The main valve is usually located in the basement, utility room, or near the water heater or laundry room. Otherwise, check outside on a wall in the utility area or in an underground panel in the yard.
Attach the feed water supply tee.
Start by placing a small bucket or rag under the cold water valve to catch any water spills. Next, use an adjustable wrench to loosen the nut connecting the cold water supply line to the shutoff valve. Disconnect the water supply line from the valve, then apply Teflon tape to the outside threads of the valve to create a watertight seal. Secure one end of the feed water adapter tee onto the shutoff valve, and the cold faucet line onto the opposite end. Use a wrench to tighten and secure the connections, being careful not to overtighten them. Push the water supply tube onto the inlet valve, then tighten the nut a half turn past hand tight.
Mount the RO sink faucet.
With the RO faucet location prepared, you can proceed to install the fixture. The installation method may differ based on the style of faucet, among other factors. However, the following instructions apply to most RO faucet installations:
- Following the manufacturer’s instructions, use the provided mounting hardware to mount the RO faucet onto the sink or countertop surface. For RO faucets with an air gap, route the corresponding brine/wastewater tubes through the installation hole first, then attach them to the faucet base. Lightly pull on the tubing to ensure they are fully inserted and secure.
- Feed the faucet stem through the opening. From the underside of the sink or countertop, install the required hardware and attach the filtered water line tubing to the faucet stem. Ensure all the faucet connections are secure and the tubes are accessible. Position the faucet in the desired direction, and tighten the hex nut to hold it in place.
Install the RO drain saddle.
The drain saddle (or clamp) connects the RO drain tube to the sink drain pipe. This allows the RO system to discharge “reject” water to the home’s drainage system. To install the drain saddle, locate and mark a drilling spot on the drain pipe. The drilled hole should ideally be above the sink p-trap on the vertical or horizontal tailpiece, and before the garbage disposal, if you have one. Additionally, the hole should be positioned at the top or side of the pipe.
At the marked location, drill a hole of the appropriate size through one wall of the drain pipe. Do not drill through both sides of the pipe. Next, position both halves of the saddle on the drain pipe. You can use a drill bit or screwdriver to align the drilled hole and the drain saddle port. Use a screwdriver to securely tighten the clamp to the pipe with the supplied bolts and nuts. Ensure they are not overtightened, but rather snug. Lastly, firmly push the drain line tubing into the drain saddle’s front port.
Prepare the RO storage tank.
The RO storage tank only requires one connection. First, wrap Teflon tape clockwise around the threads of the nipple at the top of the tank. Next, hand-screw the provided tank elbow valve onto the nipple, ensuring that you avoid cross-threading. Move the tank into position beneath the sink. Sit it directly below the RO faucet, if feasible.
Mount the RO manifold and install the filters.
First, select a spot inside your under-sink compartment to install the RO manifold. In most installations, the manifold is mounted on the right wall near the cabinet front. However, you can use whichever wall is more convenient for your space. Refer to the manufacturer’s specifications for the minimum height of the assembly above the floor. This will help ensure there’s enough room to remove the filter cartridges when necessary.
To mount the RO manifold:
- Hold the RO assembly up to the wall surface where it will be installed. Use a pencil to mark locations for the manifold screws, then drill pilot holes.
- Install the manifold at the marked location with the provided screws.
To install the filter cartridges:
- Remove the filter cap and inspect the filter cartridges for damage. Verify that the O-rings are present and seated correctly in the grooves.
- Record the expected replacement date on each filter label as directed.
- Install each filter with the matching symbols on the manifold and the filter.
- Align the cartridge with the filter head, then press upward to engage the key. Next, twist the cartridge clockwise until it locks securely into place. (This step may be different, depending on the system.)
Connect all the tubing.
RO system tubing is generally color-coded and/or numbered for easy and clear connections. The tubing configurations will vary by manufacturer, but they typically include:
- Feed water (inlet) tube: runs from the cold water supply valve or adapter to the inlet port of the first canister on the RO unit (the pre-filter).
- Filtered water tube: extends from the outlet of the RO system’s last canister filter to the RO faucet stem under the sink.
- Storage tank tube: stretches from the valve on the top of the storage tank to the “TANK” or inlet port on the RO manifold.
- Drain (wastewater) tube: leads from the drain port on the RO membrane housing to the drain saddle clamp installed on the sink drain pipe.
- Air gap assembly tubes (for certain faucet models): A smaller tube (usually 1/4”) runs from the membrane to an air gap fitting positioned below the faucet body. A second, larger tube (typically 3/8”) extends from the air gap fitting down to the main drain saddle on the sink drain pipe.
Before connecting the tubing for your RO system, make sure to consult your model’s diagram for specific connections and color codes.
Pro Tip: When cutting tubes, slice them at a 90-degree angle to prevent leaks.
Sanitize, pressure-test, and flush the system.
After installing your RO system, several steps are necessary to ensure the system’s safety and effectiveness.
Sanitize the system.
First, shut off the water supply and open the RO faucet for several minutes for the tank to empty. Loosen the tank elbow on the RO storage tank and detach the tube. Use the included eyedropper or syringe to add 3 mL of hydrogen peroxide or 5.25% liquid household bleach into the open end of the tube. Reconnect the tube and re-tighten the tank nut. The system will be thoroughly sanitized during the pressure test and purging steps.
Pressure-test system.
Next, turn on the cold water supply and open the RO faucet until the water runs smoothly with no air bubbles or spurts. Turn off the RO faucet and let the water flow through the RO system. Full pressure will build up in the system within several hours. As the unit is pressurized, inspect joints, fittings, and tubing for leaks. You can invest in a leak detection system to make this step easier. If you locate any leaks, shut off the water supply line and repair them accordingly. If problems persist, refer to the troubleshooting chart in your manual or call your manufacturer’s customer care number. If there are no leaks, the pressure test is complete.
Flush the system.
Finally, drain the system by leaving the RO faucet on and letting it purge completely for 24 hours. This helps flush impurities out of the filter cartridges and membrane. The water will initially flow at a slow trickle, then speed up as the purging is complete. Close the RO faucet after 24 hours and re-check for leaks. For new installations, it is recommended that you drain the system three times before use. Once the system is fully purged, you can begin consuming the water.
Maintaining Your Reverse Osmosis Water Filter System
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Once you are satisfied with the system’s performance, you can create a maintenance schedule to keep it running optimally for as long as possible. You’ll typically need to replace the RO filters every 6 to 12 months and the membrane once every two to five years. The exact frequency will depend on the system, water quality, and usage. You can set reminders on your phone or calendar to replace your filter periodically. That way, you don’t forget to do so.
Shop SpringWell’s Reverse Osmosis Systems
When you purchase an RO water filtration system from SpringWell, you receive all the necessary parts for installation. Also included is a detailed installation guide and a comprehensive video walkthrough to ensure a smooth and simple setup, even for beginners. For ongoing convenience, consider subscribing to have fresh replacement filters delivered to you as needed.
If you need assistance with choosing, installing, or maintaining your RO system, our expert team is here to help. Call us at 800-589-5592 or schedule a free consultation for personalized support.