What Is Reverse Osmosis? How RO Systems Work

How Reverse Osmosis Works

Reverse osmosis is the most advanced residential water filtration technology available. Unlike standard carbon filters that rely on chemical absorption, reverse osmosis uses a physical barrier — a semi-permeable membrane with pores smaller than 0.001 microns — to block contaminants. Think of it like a microscopic sieve that only lets water molecules pass through while catching everything else.

Here is the science made simple. In natural osmosis, water flows from an area of low mineral concentration through a membrane into an area of high concentration, equalizing the two sides. Reverse osmosis reverses this process. By applying pressure to the contaminated water side, you force water molecules through the membrane in the opposite direction, leaving contaminants behind as a concentrated brine that drains away.

A standard under-sink reverse osmosis system for Orlando homes uses five filtration stages. First, a sediment filter removes sand, rust, and particles larger than 5 microns. Second, an activated carbon filter removes chlorine, chloramines, and organic chemicals — chlorine must be removed first because it damages the delicate RO membrane. Third is the RO membrane itself, which blocks 95-99% of dissolved solids, heavy metals, and microorganisms. Fourth, a post-carbon polish filter removes any residual taste or odor. Fifth, an optional remineralization stage adds back healthy minerals like calcium and magnesium that the membrane stripped out.

What RO Systems Remove

Orlando's water comes primarily from the Floridan Aquifer and is treated at municipal facilities before distribution. While it meets all federal safety standards, several contaminants persist that a reverse osmosis system effectively removes:

Notice the PFAS category. These "forever chemicals" are increasingly found in Central Florida water sources and are resistant to standard filtration methods. An RO membrane is one of the few residential treatments proven to effectively remove them. For families concerned about emerging contaminants, reverse osmosis is the gold standard.

RO System Components Explained

Understanding the components helps you make informed decisions about sizing, maintenance, and performance:

• Sediment pre-filter (5-micron): Protects the RO membrane from sand and sediment common in older Orlando neighborhoods with aging infrastructure. Replaced every 6-12 months.
• Carbon pre-filter: Removes chlorine and chloramines. Critical because chlorine oxidizes and degrades the RO membrane over time. A burned-out carbon filter means faster membrane failure.
• RO membrane: The heart of the system. Produces 50-100 gallons per day (GPD) for typical under-sink installations. Higher GPD ratings suit larger families or high-usage households.
• Storage tank: Stores 3-4 gallons of purified water under pressure, providing instant filtered water without waiting for the membrane to produce more.
• Post-carbon filter: Polishes water before it reaches your faucet. Removes any residual taste from the storage tank or plumbing.
• Remineralization stage (optional): Adds calcium and magnesium back into purified water. Improves taste and raises pH slightly from the RO membrane's typical 5.5-6.5 range.

RO vs. Other Filtration Methods

Orlando homeowners have several water filtration options. Here is how reverse osmosis compares:

Carbon filters are cheaper upfront but only remove chlorine and some organic chemicals. They cannot remove dissolved minerals, heavy metals, fluoride, or PFAS. If you want truly pure drinking water, reverse osmosis is the only residential option that removes everything.

Frequently Asked Questions

RO Systems in Orlando Homes

Orlando homeowners have unique water quality considerations when choosing a reverse osmosis system. The Floridan Aquifer water contains moderate hardness levels and chloramine disinfection, which affects RO system selection and maintenance frequency:

• Water hardness: Orlando tap water averages 10-15 GPG hardness. While RO removes hardness minerals (calcium, magnesium), this means the membrane works harder to remove dissolved solids. Pre-filters in Orlando should be replaced every 6 months instead of 12 to handle the mineral load.
• Chloramine disinfection: Orlando uses chloramines (chlorine + ammonia) for water disinfection. Chloramines are more stable than chlorine but cause faster membrane degradation. Choose an RO system with a chlorine-resistant TFC (thin-film composite) membrane for longer membrane life.
• Humidity: Orlando's 75% average humidity means storage tanks can develop mildew if not properly sealed. Ensure your RO system has a well-sealed tank and replace the tank annually if you notice odors.

When to Choose Reverse Osmosis

Not every Orlando home needs reverse osmosis. Here is when RO makes sense:

• You have concerns about lead, fluoride, PFAS, or arsenic in your water
• You use the water for cooking or infant formula preparation
• You want the purest drinking water available
• Water tastes or smells unpleasant despite carbon filtration
• You have a private well and want comprehensive contaminant removal
• You are concerned about emerging contaminants like pharmaceutical residues

If your only concern is chlorine taste, a carbon filter is sufficient. RO is the nuclear option — maximum contaminant removal at a higher cost. Choose it when the contaminants in your water justify the investment.