RO Drain Clamp | 1/4" | Residential

A residential RO drain clamp — the saddle-style clamp that connects an RO system's reject-water (concentrate) tube to the standard 40mm PVC drain pipe under your sink. The proper installation method for RO discharge, used universally in residential under-sink RO installations.

What RO Drain Connection Looks Like

Reverse osmosis produces two output streams: permeate (the clean water you drink) and concentrate / reject (the brine left behind after the membrane filters out dissolved solids). The reject is discharged into the household drain plumbing — typically the same PVC pipe that takes wastewater from your kitchen sink.

A drain clamp is the proper way to make this connection:

• Saddle-style — wraps around the existing drain pipe without cutting it
• Self-adhesive sealing pad — creates a watertight seal against the drain pipe
• Drilled aperture — installer drills through the PVC inside the clamp footprint after installation
• Tube connection — 1/4" tube push-fits into the saddle's outlet port

This is the standard plumbing-trade-recognised RO drain connection. Most plumbing codes specifically reference drain saddles for RO and ice maker waste connections.

Why Not Just Tee Into the Drain Pipe?

Cutting the existing PVC drain pipe and installing a tee fitting would also work — but it's significantly more work:

• Requires draining the pipe and cleaning it before cutting
• Needs PVC primer, solvent cement, and a sleeved tee
• Creates a permanent modification to the drain system
• Trade-required work in many jurisdictions

A saddle clamp is a DIY-friendly alternative — bolt on, drill through, connect tube. 15 minutes total install time.

Installation

1. Position the clamp on the 40mm PVC drain pipe at the desired location (typically above the P-trap, on the sink-side drain)
2. Apply the self-adhesive sealing pad to the pipe aperture inside the clamp footprint
3. Bolt the clamp tight around the pipe
4. Drill through the clamp's central aperture into the PVC (small drill bit matching the tube ID)
5. Push the 1/4" reject tube into the clamp's outlet port
6. Test by running water through the system — confirm no leakage at the clamp

Specifications

• Tube connection: 1/4"
• Pipe compatibility: 40mm nominal PVC drain pipe
• Sealing: self-adhesive sealing pad included
• Installation: bolt-on saddle clamp with drilled-through aperture
• Application: residential RO systems, ice maker waste lines