← Technology WikiPE Tubing (Food-Grade)
Food-grade PE (polyethylene) tubing — usually 1/4-inch — carries water between stages in RO systems; the wrong tubing leaches taste or bursts under pressure.
How it works
- Standard: 1/4" OD LLDPE tubing, NSF-51 listed for drinking water.
- Color coding is conventional: white/blue for product water, red for hot, black for drain — not standardized, so document YOUR scheme.
- Pressure rating must exceed system max (tank pressure + pump spikes).
- Cut square and fully insert into quick-connect fittings — most 'fitting leaks' are actually bad tube cuts.
Key specifications
| Standard size | 1/4" OD |
| Material | Food-grade LLDPE |
| Certification | NSF-51 typical |
| Colors | White/blue/red/black (conventional) |
What buyers and QC should check
- For QC: check for the NSF mark printed on the tubing itself — unmarked tubing in a 'certified' system is a common finding.
- Specify UV resistance if any run is exposed to light.
Free one-page QC checklist (PDF)
The buyer checks from this entry, condensed for the factory floor or the inspection. No signup needed.
Download free PDF checklistCommon questions
Why does my new system taste like plastic?
Usually the tubing (or a new tank) — flush per the manual. If it persists past the break-in flush, the tubing may not be food-grade.
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