Reverse osmosis (RO) water filtration systems are extremely effective in reducing a wide range of contaminants in drinking water. Typically installed as point-of-use systems, RO units are connected to single fixtures, such as under a kitchen sink directed to a separate faucet, to ensure water flowing from that fixture is thoroughly filtered. With so many different water filtration systems available on the market, it can be difficult to decide if an RO system is worth the investment. By understanding how RO systems work, as well as the pros and cons of reverse osmosis, you’ll be able to make a more informed decision for your home.
What is Reverse Osmosis?
Reverse osmosis is a water purification process that uses a semi-permeable membrane to capture ions, molecules, and other larger particles from water. When pressure is applied to one side of the membrane, water is forced through pores about 0.0001 microns small. Because these pores are so tiny, many impurities are unable to pass through. RO systems are commonly used in residential and industrial settings for producing drinking water, seawater desalination, wastewater treatments, and other applications requiring high-quality water.
How Do Reverse Osmosis Water Filters Work?
A typical residential reverse osmosis system involves six important processes. These include:
Pre-Filtration: Water enters sediment or carbon filters to remove larger particles that could damage the RO membrane.
Pressurization: Depending on the system, a pump or incoming water pressure forces pre-filtered water through the RO membrane.
Reverse Osmosis Membrane: Pores in the semi-permeable membrane allow water molecules to pass through while blocking remaining contaminants.
Permeate and Reject Streams: Pressurized water flowing through the membrane separates into permeate (purified water) and concentrate (rejected water).
Storage and Delivery: Purified water collects in the storage tank until needed.
Waste Water Disposal: Rejected water containing contaminants is typically discharged or directed to a drain. Modern RO systems often include water-saving features or additional treatment stages to minimize wastewater.
Kind Water System’s RO System
Kind Water’s 6-Stage Reverse Osmosis Drinking Water System produces up to 50 gallons of clean drinking water daily. Our unique system includes a four-step pre-filtration and two-step post-filtration process that effectively reduces a range of contaminants.
4-Stage Pre-Filtration Process
Stage 1. Sediment Filter
Pressurized city water or well water enters the RO system’s sediment pre-filter, which traps dirt, silt, and other suspended solid particles.
Stage 2. Granular Activated Carbon (GAC) Filter
The GAC filter captures chlorine and similar molecules that affect water odor and taste.
Stage 3. RO Membrane Filter
Pressurized water is directed to the RO membrane, which limits salt, heavy metals, and other impurities from continuing to flow through to the plumbing fixture.
Stage 4. Granular Activated Carbon (GAC) Filter
Another GAC filter seizes any particulates that made it through the other filtration layers.
2-Stage Post-Filtration Process
Stage 5. Inline Charcoal Filter
This serves as the final post filter to remove any remaining taste or odors in the water.
Stage 6. Inline Remineralization Filter
Beneficial minerals such as calcium and magnesium are removed during RO. This filter reintegrates some of these minerals, improving water taste and balancing pH levels.
What Does Reverse Osmosis Remove?
RO systems are effective at removing up to 99% of dissolved solids like salts and minerals, nitrates, organic compounds, and chemicals like chlorine, chloramines, pesticides and herbicides, and some PFAS. They are also capable of reducing heavy metals and biological contaminants, though RO systems alone may not be able to eliminate these impurities.
Pros and Cons of Reverse Osmosis
There are advantages and disadvantages of reverse osmosis systems. Understanding these pros and cons is important to help you determine if an RO system is right for your home.
Advantages of Reverse Osmosis Filters
Removal of Contaminants
Reverse osmosis systems effectively remove a wide range of contaminants and leave water largely free from impurities.
Improved Taste and Odor
By eliminating impurities, RO systems leave water with a refreshing taste ideal for drinking and cooking.
Versatility
RO systems are compact and versatile, as they can be installed around your home out of the way but still easily accessible.
Reliability
With regular filter replacement, which involves simply switching out filter cartridges, RO systems offer long-term performance and reliability for many years.
Cost-Effective
While the initial investment may be higher than some other filtration methods, the long-term cost-effectiveness RO systems provide is significant, especially compared to cheaper options like pitcher filters. See how our RO system compares in performance to typical refrigerator and pitcher filters.
Disadvantages of Reverse Osmosis Filters
Despite several key benefits, filtering water through reverse osmosis does have a few minor drawbacks to consider before purchase.
Wastewater Generation
RO systems produce wastewater as a byproduct of filtration. While this can be mitigated with advanced systems, the environmental impact of water wastage should be considered.
Mineral Stripping
Some critics argue that RO filtration removes beneficial minerals and contaminants from the water, potentially leading to mineral deficiencies in the diet. However, this concern can be addressed by considering remineralization options for RO-filtered water.
Maintenance Variability
Maintenance can be very easy or potentially complicated, depending on the particular RO system you use. All systems require regular filter changes, membrane cleaning, or other upkeep tasks. Consumers should research maintenance requirements upfront to ensure they choose a system that aligns with their preferences and lifestyles.
Is RO Right for Your Home?
Investing in a reverse osmosis system depends on your water quality needs, budget, and environmental considerations. If you’re deciding between different systems, our guide on the most common types of water filters can help you choose the best option for your home. RO could be the perfect solution if you’re looking for a reliable, cost-effective, and fairly low-maintenance option for cleaner, safer drinking water.