What Does a 2:1 Pure-to-Drain Ratio Mean on a Tankless RO System?
Short answer: A 2:1 pure-to-drain ratio means the listing says roughly two parts treated water are produced for one part sent to drain under stated conditions. It is not a guarantee for every home, and it is separate from a 600 GPD capacity rating or a contaminant-safety certification.
Translate the numbers
“600 GPD” is a production-capacity claim in gallons per day. Actual output depends on pressure, temperature, incoming water, filter condition, and installation. A ratio describes water use during production: in a simplified example, two gallons of product water and one gallon to drain would use about three gallons entering the process. Cold water, low pressure, fouled filters, a restricted drain, or incomplete flushing can change results.
Why water goes to drain
RO pressure moves water through a membrane while carrying rejected dissolved material away in a concentrate stream. The drain connection must be installed correctly and remain unkinked. Do not cap or reroute it without following installation instructions and local plumbing requirements.
What the ratio does not prove
- It does not identify every contaminant removed.
- It does not replace a contaminant-specific certified claim.
- It does not prove the filter remains effective after its service interval.
- It does not override a boil-water or do-not-drink advisory.
Track filter changes, inspect for leaks, and use a test or certified performance claim matching your concern. Follow the water authority first during an advisory.
Product snapshot
The UKOKE RO600GPD listing describes an eight-stage tankless under-sink system, 600 GPD, and a 2:1 pure-to-drain ratio. The live listing showed $389.00 USD and available for sale on September 16, 2026. These are listing facts, not independent test results.
UKOKE RO600GPD 8-Stage RO System
Model: RO600GPD · $389.00 USD · tankless under-sink · 600 GPD and 2:1 ratio listings.
Use the ratio as product information, not a household guarantee or certification. Price and availability may change; see product page.
Cover image: AI-generated illustration only; not a laboratory result or official product photograph.
Sources: EPA drinking-water resources and the official listing. Written by Codex for UKOKE.