What Is Reverse Osmosis Water? Your Comprehensive Guide
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What Is Reverse Osmosis Water? Your Comprehensive Guide
Reverse osmosis water is water that has been purified by forcing it through a semi-permeable membrane that can remove more than 90% of many dissolved contaminants, including heavy metals like lead and arsenic, as well as certain PFAS chemicals.
In simple terms, it’s one of the most highly filtered types of drinking water available for residential use. This comprehensive guide breaks down everything you need to know about reverse osmosis: how it works, the pros and cons, and when you might need a reverse osmosis system.
If you’re considering installing a reverse osmosis (RO) system, explore expert solutions for home water filtration systems or call a YES! expert at 844-216-9300.
Table of Contents
How Do Reverse Osmosis Systems Work?
A reverse osmosis system is a water filtration system. Reverse osmosis works by using pressure to push water through a very fine semi-permeable membrane. This membrane acts like a microscopic filter that allows water to pass while blocking contaminants.
Think of it like how a screen window or door lets fresh air in while keeping bugs out because the bugs are larger than the spaces within the mesh screen.
Instead of relying on chemicals or electricity, RO systems use water pressure and layered filtration to progressively clean water in stages. Each stage targets different types of impurities, from large particles like sediment to microscopic dissolved contaminants like lead and nitrates.
Step-by-Step: The Reverse Osmosis Process
Here’s how the reverse osmosis process works inside a typical home system:
Water Enters the System (Feed Water)
Tap water flows into the reverse osmosis unit through a dedicated supply line connected to your home plumbing. Water that goes into an RO system is known as feed water. After it has gone through the process, it’s called permeate water.Sediment Filtration
The feed water then goes into the sediment pre-filter, which is the first step in filtration. The first filter removes visible particles like dirt, rust, sand, and debris. This filter protects the rest of the system from clogging or damage.Carbon Pre-Filtration
The next filter removes chlorine and chloramine from the water, which can also damage the RO membrane. These chemicals can cause oxidation and membrane degradation.Reverse Osmosis Membrane Filtration
Here’s where reverse osmosis occurs—the core stage of the system. Using pressure, water is forced through a membrane with extremely tiny pores (about 0.0001 microns). This is where the dissolved contaminants are removed, including metals, salts, and nitrates.Post Carbon Filtration
As the permeate water moves through the final carbon filter, any odd tastes or smells are removed before the water enters the storage tank.Storage or Direct Delivery
Most traditional systems come with a storage tank so purified water is ready on demand. Newer “tankless” systems filter water in real time for faster flow and a more compact design.
Source references: Food and Drug Administration, U.S. Environmental Protection Agency (EPA), and Centers for Disease Control and Prevention (CDC)
What Does Reverse Osmosis Remove?
At this point, you might wonder what reverse osmosis gets rid of in your water. After all, anyone can claim cleaner water with a purification system.
RO systems can remove:
Arsenic
Bacteria
Chlorine
Copper
Fluoride
Herbicides
Ions
Lead
Nitrate
Pesticides
PFAS (“forever chemicals”)
Protozoa
Sodium
Sediment
Viruses
The EPA recognizes reverse osmosis as one of the “proven technologies that can achieve high removals of a broad range of contaminants at once.”
What Are the Pros and Cons of Reverse Osmosis?
Like any water treatment method, reverse osmosis has both advantages and limitations.
Pros:
Highly effective contaminant reduction
Improves the taste and smell of water
Removes sodium in drinking water
Works without electricity in standard systems
Can reduce bottled water use, which reduces plastic waste
Doesn’t take up a lot of space
Cons:
Produces wastewater during filtration
Takes longer to get water than basic filters
Removes some beneficial minerals like calcium and magnesium
Needs maintenance, like filter replacement
When Should You Consider a Reverse Osmosis System?
A reverse osmosis system may be a good fit if your home water contains elevated levels of contaminants or if you’re unsure about your water quality.
Households with specific health concerns—such as those monitoring sodium intake or wanting to limit exposure to contaminants like lead or nitrates—may also benefit from reverse osmosis as part of a broader water-quality strategy.
You may want to consider RO if you have:
Elevated lead or copper levels
Arsenic or nitrate contamination (common in some well water)
High total dissolved solids (TDS)
Noticeable chlorine taste or odor
Concerns about PFAS exposure
Aging plumbing that may affect the water
Many homeowners focus on contaminants like lead, arsenic, or PFAS, but water quality includes other factors, too, like hardness. Knowing whether your water is hard or soft can help you choose the right combination of water treatment options (for example, a water softener plus reverse osmosis).
For more information on water softeners and why hardness matters, see our guide on how to choose the best water softener salt.
How to Test Your Water
Before installing a reverse osmosis system, it’s good to understand what’s actually in your water. Testing helps identify specific contaminants so you can choose the right filtration solution for your home.
Here are the most common ways to test your water:
Local utility water quality reports (for municipal systems)
At-home test kits for basic screening
Professional plumbing or water quality inspection
Learn more about how population growth affects water quality.
What Types of Reverse Osmosis Systems Are Available?
Reverse osmosis systems come in several configurations based on space, performance, and water demand.
Waterdrop G3
A modern tankless RO system designed for speed and efficiency.
Space-saving design
Faster flow rate than traditional tank systems
Lower wastewater ratio (2:1 pure to drain).
iSpring RCC7AK
A 6-stage under-sink system that includes an alkaline remineralization filter to restore natural minerals and improve taste.
Popular for balanced, “spring-like” water taste
Strong choice for homeowners wanting mineral reintroduction
Frequently praised for its easy installation and performance
APEC ROES-50
A widely used 5-stage system known for reliability and low maintenance.
Long-lasting filters
Consistent performance over time
One of the most installed RO systems in the U.S.
Tankless RO systems are becoming increasingly popular due to compact design and improved efficiency, especially in newer homes and kitchen remodels.
Installation Location Types
Various RO systems also differ based on where they’re installed. Options include countertop and under-the-sink systems.
A countertop RO system is a free-standing unit that can sit alongside other household kitchen appliances on the counter. An under-the-sink system is connected to the kitchen sink, nestled below it among its plumbing components.
How Is Reverse Osmosis Installed?
Each installation process will differ based on various factors. These may include the type of plumbing system in your home, your selected RO system, and the space available.
However, most installation jobs include the following steps:
Turn off or disconnect running water from the sink (if the RO system is getting attached to the plumbing).
Take note of the materials of the plumbing system (a different method will be used if the components are metal vs. ceramic).
Mount the RO faucet.
Mount the stop valve.
Install the drain saddle valve.
Place the original plumbing parts back in their proper places.
Install the cartridge filter.
Install the RO system.
Add the supply tank.
Add any other tubing needed.
Test the system.
Diagnose and fix any problems.
It may sound easy, but anything involving plumbing can be complicated. Professional installation can help ensure the system is set up correctly and operating efficiently.
Drink Cleaner Water Today
You deserve clean drinking water in your home; a reverse osmosis system can make it happen. With minimal effort, you can enjoy access to water free from contaminants every time you turn the faucet.
If you have questions about the benefits, cost, special offers, or installation of a reverse osmosis system, speak with our team! Give your local plumbing professionals a call at 844-216-9300.
