Reverse Osmosis System Installation: Under-Sink vs. Whole House

Under-Sink RO Installation

Under-sink RO installation is the standard choice for 90% of Orlando homeowners. The system fits neatly under your kitchen sink, connected to your cold water line, with a dedicated faucet on your countertop or sink deck. Here is what the installation process looks like:

Space requirements: A standard under-sink RO system (5-stage) requires approximately 20 inches of vertical clearance and 12 inches of width under your sink. Most standard kitchen sinks have adequate space, but if you have a garbage disposal or large water filter already installed, you may need to consolidate or choose a more compact model.

Plumbing connections needed:

• Cold water supply: Connects to the cold water line under your sink using a saddle valve or dedicated shut-off valve. Orlando homes with copper plumbing use compression fittings; PEX homes use push-fit connectors.
• Drain line: Runs from the RO system to a floor drain, standpipe, or garbage disposal inlet. The drain line must have an air gap device to prevent backflow (required by Orlando plumbing code).
• RO faucet: Installed through a hole in your countertop or sink. If your sink has no spare hole, a 3-hole faucet assembly is available.
• Storage tank: A 3-4 gallon pressurized tank sits under your sink, providing instant filtered water without waiting for the membrane to produce more.

Time required: Professional installation takes 2-3 hours for a standard under-sink RO. This includes mounting all components, making connections, pressure testing, flushing the system for 30 minutes, and verifying performance with a contaminant test kit.

Whole-House RO Installation

Whole-house RO systems treat all water entering your home, providing pure water at every faucet, shower, and appliance. This is a major installation that only Orlando homes with severe water quality issues need:

Space requirements: A whole-house RO system requires 2-4 square feet of floor space and 8-10 feet of vertical clearance. Typical installation locations are the garage, utility room, or a dedicated equipment room. The system includes multiple tanks (pre-filtration, RO membrane, remineralization) and a large storage tank.

Plumbing connections needed:

• Main water line: Installed after the main shut-off and pressure regulator, before water branches to individual rooms.
• Multiple drain lines: Whole-house RO produces significant wastewater (3-5 gallons per gallon of purified water). A dedicated drain line with proper air gap is essential.
• Electrical supply: Requires a dedicated 110V circuit for automated controls and pumps.
• Pressure regulation: Additional pressure regulator needed to handle the high flow rate and prevent membrane damage.

Time required: Whole-house RO installation takes 4-8 hours and typically requires a licensed plumber with water treatment experience. Orlando plumbing permits may be required for whole-house installations, adding $50-150 in permit fees.

What Professional Installation Includes

When you hire a professional RO installer in Orlando, here is what you get:

1. Site assessment: The technician evaluates your sink space, plumbing configuration, and drain accessibility to ensure proper system placement.
2. Pre-installation flush: The system is flushed for 15-30 minutes before installation to remove manufacturing residues and carbon dust from the filters.
3. Professional mounting: All tanks, filters, and the faucet are securely mounted and connected.
4. Pressure testing: All connections are tested at 60-80 PSI to verify there are no leaks. This is critical — a single leak under your sink can damage cabinets and flooring.
5. Performance verification: A contaminant test strip or TDS meter confirms the system is removing contaminants at the expected rate (95-99% for lead and other heavy metals).
6. Customer orientation: The technician shows you how to check filter status, change filters, and troubleshoot common issues. You receive written maintenance schedules and warranty documentation.

Permitting and Orlando Codes

Orlando has specific plumbing codes that affect RO system installation:

• Air gap requirement: Orlando plumbing code requires an air gap device on all RO drain lines. This prevents back-siphoning of contaminated water into the clean supply. The air gap is a small device installed on the countertop or sink deck and costs $5-10.
• Drain line connection: RO drain lines must connect to a floor drain, standpipe, or garbage disposal with an air gap. Direct connection to a sink P-trap is NOT permitted in Orlando.
• Faucet drilling: Countertop drilling for RO faucets is allowed in Orlando. For granite or quartz countertops, use a professional drill kit to avoid cracking.

Orlando-Specific Maintenance Tips

Orlando's water quality and climate affect RO system maintenance:

• Pre-filter frequency: In older Orlando neighborhoods with aging pipes, replace pre-filters every 6 months. In newer developments, 12 months may be sufficient.
• Membrane life: Orlando's chloramine disinfection reduces membrane life. Expect 2-3 years instead of the standard 3-4 years.
• Storage tank: Orlando's humidity means tanks can develop mildew. Sanitize the tank annually by flushing with a food-grade hydrogen peroxide solution.
• Water pressure: Orlando's 40-80 PSI municipal pressure is ideal for RO. If your home has a booster pump installed for the water softener, check that it has not raised pressure above 80 PSI — this can damage the RO membrane.