Reverse osmosis (RO) is one of the most effective technologies for removing water contaminants and purifying drinking water. While systems vary, proper installation is crucial to achieve clean, healthy water for your household.
In this guide, we’ll walk you through a complete DIY reverse osmosis system installation, using the industry-leading iSpring RCC7AK as an example model. We’ll cover:
- How reverse osmosis purification works
- What parts are included in the system
- Where to install the RO components
- Step-by-step installation instructions
- Tips for trouble-free operation
- Frequently asked questions
Follow along and you’ll gain the skills to install your iSpring reverse osmosis system with confidence. Let’s get started!

How Does Reverse Osmosis Work?
To understand RO system setup, it helps to first learn what this technology actually does. Reverse osmosis utilizes a multi-step process to reduce contaminants:
1. Water Flows Through a Prefilter
Tap water enters and flows through a sediment prefilter to trap particles like silt, rust and sand. This protects later filters.
2. The RO Membrane Filters Out Contaminants
The filtered water then enters the RO membrane. This is the heart of the system – it removes up to 99% of contaminants by allowing only water molecules to pass through its microscopic pores.
3. Purified Water Flows To Storage
The freshly purified water exits the RO module and flows to a storage tank. Now free of contaminants, it is ready for drinking and cooking use.
4. The Rest Flows to Drain
Water that does not pass through the RO membrane exits as a concentrated stream, carrying removed substances down the drain.
Now that you understand how reverse osmosis systems function, let’s look at what components make up a complete installation.

What’s Included in the iSpring RCC7AK RO System
The iSpring RCC7AK is a premium 5-stage reverse osmosis system. Here are the components included:
- Stage 1 – PP Sediment Filter: Traps silt, sand, dirt & debris
- Stage 2 – GAC Carbon Filter Block: Reduces chlorine, tastes, odors & chemicals
- Stage 3 – CTO Carbon Filter Block: Further reduces particles, chlorine & contaminants
- Stage 4 – 75GPD RO Membrane: Filters out up to 99% of contaminants
- Stage 5 – Inline Mineralizing Post Filter: Adds healthy minerals back into purified water
- 3.2 Gallon Pressurized Tank – Stores purified water ready for use
- Fully Assembled Faucet – Delivers filtered water conveniently.
- Feed Water Adapter Valve – Connects easily to existing plumbing
- Tubing Set – Food grade tubing links all components
- Wrench & Fittings – For secure, leak-free connections
- Drain Saddle Valve – For RO wastewater drainage
- User Manuals – For simplified installation and operation
With all cartridges pre-loaded in the housing pods and the faucet already built, the system arrives ready for installation right out of the box.
Where to Install the RO System Components
Proper placement of the reverse osmosis system ensures optimal performance and space utilization in your home. Here are the recommended locations for each component:
- Prefilter Housings: Under the kitchen sink. Mount to cabinet wall or sink top.
- RO Filter Housing: Under sink or in adjacent basement area.
- Storage Tank: Basement, crawl space or kitchen cabinet.
- Faucet: Pick an open area on your sink top. Many choose near the existing faucet. Consider an unused soap dispenser hole.
- Drain Connection: Under sink drain pipe.
Locate parts close together to minimize tubing runs. Now let’s look at the installation sequence.

Step-By-Step RO System Installation
Follow these steps to properly install your iSpring reverse osmosis system:
Step 1 – Mount Components
First, mount the filter housings and storage tank. Typical mounting options:
Under Sink Mount:
- Place 2 housings end to end and strap to back sink wall using included metal bracket
- Place 3rd housing and tank inside cabinet if space allows
Basement Shelf Mount:
- Arrange housings side by side and strap vertically to basement shelf
- Place storage tank on floor nearby
Tip: Allow space underneath to change filters and for tubing runs.
Step 2 – Install Faucet
Select your desired faucet location. Common choices:
- Open spot on sink top
- Previously used soap dispenser hole
- Drill 1/2” hole in rear sink skirt
In your chosen spot:
- Drill 1/2” faucet hole if needed
- Insert faucet base through hole
- Slide rubber washer over threads
- Mount metal washer & nut from underside
- Tighten nut with wrench to secure faucet
Don’t attach tubing yet – this comes later.
Step 3 – Mount Drain Saddle Valve
The drain saddle valve drains away concentrated waste water from the RO. To install:
- Locate the ideal spot on sink drain pipe, above p-trap bend
- Lightly sand drain pipe surface with included abrasive pad
- Place saddle valve at selected spot and tighten bolts evenly to create a seal
- Attach provided drain tubing to barbed outlet port
- Position tube end in sink for observation
Step 4 – Connect Water Supply
Now it’s time to connect the water supply line using the feed water adapter:
- Shut off cold water valve under sink and release pressure
- Disconnect existing riser tube from shutoff valve
- Screw male end of feed water adapter into shutoff valve
- Use included ferrule and nut to reconnect riser tube to adapter
- Turn water back on – adapter will now supply unfiltered water to the RO system
Step 5 – Link System Components
The final step is connecting the integrated tubing between the RO components:
- Push colored tubing into corresponding ports on each filter housing
- Connect tubing between housings, faucet, tank and drain saddle
- Label tubes to keep track of each one
- Use wrench to tighten compression nuts and ensure leak-free connections
With all parts installed and connected by tubing, your RO system is ready to use!

Getting the Most From Your RO System
Once installed, just a bit of maintenance keeps your reverse osmosis system running optimally:
- Replace prefilter cartridges every 6 months to maintain flow rate
- Replace the RO membrane every 2-3 years for optimal purification
- Keep storage tank bacteria-free by sanitizing yearly with bleach
- Check for leaks occasionally and tighten fittings if needed
- Test purified water annually to verify proper contaminant reduction
Following the manufacturer’s maintenance schedule keeps the system performing like new for years of reliable use.
Troubleshooting Common RO Problems
In case any issues arise, here are some common troubleshooting tips:
Low water production:
- Replace prefilter cartridges if flow is slow
- Clean storage tank bladder yearly
- Check water pressure meets minimum psi
- Inspect RO membrane for fouling
Leaking fittings:
- Check compression nuts are fully tightened
- Replace worn tubing o-rings
- Apply proper ferrule and nut placement
Milky colored water:
- Drain storage tank fully
- Replace old membranes
- Flush newly installed filters before use
Faucet leaks:
- Tighten stem screw in faucet handle
- Replace faucet cartridge o-rings
- Clean faucet inlet water screen
Contact us directly if you need help getting your RO system running properly again.

FAQs About RO Installation
Here are answers to some commonly asked questions about reverse osmosis system setup:
Where is the best place to install the faucet?
Most often, directly on the sink top or using an existing soap dispenser hole. Under counter and countertop options are also available.
How do I ensure watertight tubing connections?
Carefully insert tubing fully into ports, then firmly hand tighten compression nuts until snug. Use wrench for final 1/4 turn. Don’t overtighten.
What tools do I need for installation?
Usually just an adjustable wrench, utility knife, screwdriver, and drill with 1/2″ bit. Plumbers putty if drilling a new faucet hole.
What if my tubing is too short?
Extension tubing can be purchased to lengthen the runs as needed. Cut and use connectors to integrate seamlessly.
How often should I change the RO membrane?
For optimal contaminant reduction and purified water flow, replace the RO membrane every 2-3 years. Annual testing helps confirm it’s performing properly.
Is professional installation available?
Absolutely. Our team of water quality experts can handle the entire installation for you. Contact us for pricing details.
How much water pressure is required?
40-60 psi is the recommended minimum to effectively run an RO system. A booster pump can be added if pressure is consistently lower.
Let us know if you have any other reverse osmosis installation questions. Our water specialists are always happy to help our customers!
We hope this guide gives you the knowledge to get your iSpring reverse osmosis system set up properly. Just take it step-by-step, and you’ll be enjoying purified water in no time.
For more information, contact us today to speak with a water expert. Investing in an RO system is one of the wisest decisions you can make to safeguard your family’s health. We’re here to help every step of the way!