Professional Water Treatment Installation Costs
Updated February 20, 2026
Some water treatment systems install in 30 minutes under the sink. Others require cutting into the main water line, adding electrical circuits, and running drain connections. The system type determines whether you're looking at a DIY afternoon project or a $1,000+ professional installation.
Overview
Some water treatment systems install in 30 minutes under the sink. Others require cutting into the main water line, adding electrical circuits, and running drain connections. The system type determines whether you're looking at a DIY afternoon project or a $1,000+ professional installation.
Cost Breakdown
Pro Tips
- Under-sink RO is the one system almost everyone should DIY. The $100-$300 installation cost is easy to save.
- When getting softener installation quotes, ask if the plumber will program the control valve for your specific water hardness. Generic settings waste salt and water.
- Water treatment companies often bundle installation with equipment at a significant markup. Get separate quotes for equipment and installation to compare.
- If you need electrical work (outlet for UV or softener), schedule the electrician before the plumber. The outlet needs to be in place first.
Mistakes to Avoid
- Paying a water treatment company $500 to install an under-sink RO you could install yourself in an hour.
- Hiring a general handyman for softener installation. Improper connection to the main line or incorrect programming leads to problems.
- Not installing a bypass valve on a whole-house system. Without it, you can't service the system without shutting off water to the entire house.
- Letting the installer put the UV before the softener or carbon filter. UV must be the last stage to be effective -- particles and turbidity block UV light.
When to Call a Pro
Anything connecting to the main water line should be done by a licensed plumber. Under-sink systems are DIY-friendly. If you need electrical work, hire a licensed electrician.
Bottom Line
Under-sink RO: $0-$300 (DIY recommended). Softener: $200-$500. Whole-house carbon: $200-$400. UV: $200-$400. Complete system: $500-$2,000. DIY the under-sink stuff, hire a pro for everything on the main line.