The cost is lower than I thought...

Brave:

Installation Cost of a Reverse Osmosis SystemInstallation Cost of a Reverse Osmosis System

Professional installation of a reverse osmosis (RO) system typically costs:

• Under-sink (point-of-use) systems: $100–$500, with most homeowners paying $300–$700 total when including the unit.
• Whole-house RO systems: $500–$2,500 for installation, depending on complexity, plumbing, and system size.

Key Cost Factors:Key Cost Factors:

• System type: Under-sink units are simpler and cheaper to install; whole-house systems require extensive plumbing and electrical work.
• Labor rates: Vary by region; metropolitan areas often have higher costs.
• Plumbing complexity: Older homes or limited access under sinks can increase labor time.
• Add-ons: UV sterilization, booster pumps, or remineralization filters may raise installation costs.

Many providers offer bundled deals that include both the system and professional installation, potentially saving 10–15%.