Why An Under Sink Reverse Osmosis System Is the Best
An under sink reverse osmosis system gives you clean, safe drinking water at home. You always have fresh water when you need it.
There are many ways to filter water. However, under sink RO systems are one of the best choices for your home.
Angel Water’s licensed plumbers are here to help you learn:
- What is an under sink reverse osmosis (RO) system? How does it work?
- How does it compare to other RO systems like whole house or countertop models?
- Why are under sink RO systems the best for most homes?
- What happens during installation? How easy is it to maintain?
- How can our experts help you get cleaner, better-tasting water?
So, keep reading to find out more!

What Is an Under Sink Reverse Osmosis System?
An under sink reverse osmosis system is a small but powerful water filter. It fits under your kitchen or bathroom sink.
This system uses several filters to remove dirt, chemicals, and bad tastes from your tap water. As a result, you enjoy crisp, clean, and safe drinking water available at your fingertips!
How Do Under Counter Reverse Osmosis Filters Work?
Reverse osmosis uses a special membrane to separate bad stuff from your home’s water. Here’s how a typical under sink RO system works:
Pre-filtration: First, water first goes through a sediment filter and a carbon filter. These remove dirt, chlorine, odors, and more.
RO Membrane: Next, the heart of your system—the membrane—filters out solids, minerals, and harmful particles.
Post-filtration: Then, a final carbon filter polishes the water, ensuring it tastes fresh and pure.
Storage Tank: Finally, clean water is stored in a tank. You can get it any time from your special faucet.
Under sink RO systems clean water much better than pitcher or fridge filters. Consequently, you experience better water quality without hassle.
More About the Membrane
RO membranes are typically capable of removing 90%–99% of contaminants.
Because they have microscopic pores, they effectively eliminate a wide range of contaminants. These include:
- Sediment: Sand, silt, and rust particles that can make water cloudy and affect the taste.
- Chlorine and chloramines: Chemicals that can impart an unpleasant taste and odor.
- Heavy metals: Lead, mercury, arsenic, and other potentially harmful metals.
- Dissolved solids: Minerals, salts, and other substances that make water hard.
- Microorganisms: Bacteria, viruses, and microbes that can pose health risks.
- Fluoride: While sometimes added intentionally, some individuals prefer its removal.
- PFAS (Per- and Polyfluoroalkyl Substances): A group of man-made chemicals that are persistent in the environment and can be harmful.
- Pharmaceuticals: A wide variety of medications have been detected in drinking water.
The filtration process involves forcing water under pressure through the RO membrane. Then clean water then flows to a dedicated faucet installed at your sink.
Meanwhile, the contaminants that are filtered out are flushed down the drain. Most under sink reverse osmosis systems also include a storage tank to ensure you always have pure water ready to go.
How Under Sink RO Systems Compare to Other Options
There are several types of reverse osmosis systems available. But not all are equal.
Therefore, it’s important to understand how under sink reverse osmosis systems compare to other options.
Whole House Reverse Osmosis Systems
Whole house systems filter all water entering your home. While they work very well, they also come with some drawbacks.
Pros:
- Cleans water for your whole house
- No need for a separate drinking water faucet
- Protects all appliances from mineral buildup
Cons:
- Higher initial cost
- Needs regular maintenance and filter replacements
- Some whole house RO systems waste water
- Removes beneficial minerals from all water
Why Under Sink Wins: Most families only need pure water for drinking and cooking. Thus, an under sink RO system is better for everyday use.
Countertop Reverse Osmosis Systems
Countertop units sit on the kitchen counter and connect to your existing faucet.
Pros:
- No need to install anything
- Portable and easy to move
- Costs less at first
- Good for renters
Cons:
- Takes up valuable counter space
- Slower filtration process
- Must connect and disconnect for each use
- Smaller storage capacity
- Less attractive appearance
- Often more expensive long-term
Why Under Sink Wins: Under sink systems stay hidden. Moreover, they provide instant access to pure water. They process water faster and store more filtered water for immediate use.
Portable and Pitcher RO Systems
Portable systems are designed for travel or temporary use.
Pros:
- Great for camping or traveling
- No permanent installation
- Compact storage
Cons:
- Very limited capacity
- Slow filtration rates
- Not practical for daily home use
- Frequent refilling required
- Higher cost per gallon produced
Why Under Sink Wins: For home use, under sink reverse osmosis systems are more useful and hold more water.
Why Under Sink RO Systems Are the Best Choice
An under sink reverse osmosis system gives you the perfect balance of cost and performance.
In fact, they offer a sweet spot between affordability and effectiveness. These systems cost less than whole house systems. And they simply work better than countertop or portable filters.
Initial investment typically ranges from $200 to $800. This price point makes pure water accessible to most homeowners without breaking the budget.
Unsure About Your Water Quality? Get a Free Water Test Today!
Contaminants can affect the safety and taste of your water. Get a free water test to check your water quality and see if a reverse osmosis system can help provide clean, pure drinking water.

Enjoy Space-Efficient Design
If you’re like most homeowners, kitchen counter space is precious. Because under sink systems hide completely beneath your cabinet, they leave your countertop clear for food preparation and appliances.
The only visible component is an attractive faucet that adds convenience to your kitchen.
Convenient Access to Pure Water
With an under sink RO system, pure water is always ready at the turn of a handle.
No waiting for filtration, no connecting hoses, and no refilling containers. Just instant access to clean water whenever you need it.
Lower Long-Term Costs
Whole house RO systems require expensive filter replacements for large volumes of water.
In contrast, under counter reverse osmosis filters only clean water you drink or cook with. This saves money and cuts water waste.
Easy Maintenance
Under sink systems are simple to maintain. Most homeowners can change filters themselves with basic tools.
Typically, filter replacements typically cost $50-$150 per year, depending on water usage and quality.
Understanding the Under Sink RO System Installation Process
Installing an under sink reverse osmosis system is relatively easy.
However, it’s wise to choose professional installation for the best results, though some systems offer DIY-friendly designs.
Before you start, check the space under your sink. You’ll need room for the system components. These typically include a storage tank, filter housing, and connecting lines.
Measure and Check Water Pressure
Under-sink reverse osmosis systems typically have dimensions that range from 11″ to 20″ in height, 5″ to 12″ in width, and 8″ to 11″ in depth.
Ensure you have high enough water pressure. Most systems need at least 40 PSI to function properly. If your water pressure is low, you might need a booster pump.
Installation Steps for An Under Sink Reverse Osmosis System
- Turn Off Water Supply
The first step involves shutting off the cold-water supply valve under your sink.
- Install the Faucet
Drill a hole in your sink or counter for the new faucet. It is usually 1/2 inch wide. Then, connect the faucet to the system with food-safe tubing.
- Connect to Water Supply
Next, the system connects to your cold-water line using a saddle valve or separate shut-off valve. This connection allows water to flow into the filtration system.
- Install System Components
The filter housing, RO membrane, and storage tank are mounted under your sink. These components connect with color-coded tubing for easy identification.
- Connect Drain Line
A drain line connects to your sink’s drainpipe to dispose of rejected water during the filtration process.
- Test the System
After installation, the system is flushed and tested to ensure proper operation. So the water may taste slightly unusual at first as the filters activate.
Professional vs. DIY Installation of Under Sink RO Systems
While some homeowners install their own systems, professional installation by a licensed plumber offers many advantages:
- Ensures proper connections and sealing
- Includes system testing
- Often includes warranty coverage
- Saves time and prevents mistakes
- Handles unexpected installation challenges
If you want to do it yourself, you’ll need:
- Basic plumbing skills
- Tools like a drill, wrenches, and a cutter
- 2 to 4 hours of time
- Care to avoid leaks
- To check if DIY voids your warranty
Some homeowners choose to install their own under sink RO systems. But professional installation by the licensed plumbers at Angel Water ensures your system is set up correctly, safely, and efficiently.
Our team handles everything so you can enjoy pure water with zero hassle.
Get Peace of Mind with an Under Sink RO System from Angel Water
Investing in an under sink reverse osmosis system is an investment in your health, well-being, and the quality of your drinking water.
Say goodbye to unpleasant tastes, smells, and potential health problems. With an under-sink RO system, you’ll enjoy:
- Superior water quality: Experience water that is clean, crisp, and refreshing.
- Improved taste of beverages and food: Your coffee, tea, and recipes will taste better with purified water.
- Cost savings: Reduce your reliance on bottled water, saving you money and reducing plastic waste.
- Convenience: Enjoy instant access to clean water directly from your dedicated faucet.
Ready to upgrade your kitchen with the best under sink reverse osmosis system?
At Angel Water, we offer a range of high-quality RO systems to fit your needs and budget. Our knowledgeable team can help you choose the perfect system and provide professional installation services.
Take the first step to clean, pure water for your loved ones — reach out to us today!
Ready for Cleaner Water? Schedule an Appointment Now!
Ensure your family has access to clean, great-tasting water. Schedule an appointment with our specialists today to learn how a reverse osmosis system can purify your drinking water.