Treatment technology profile
Reverse Osmosis (RO)
Semi-permeable membrane separation removing dissolved minerals, heavy metals, and persistent fluorinated chemicals down to 0.0001 microns.
Capability, not a blanket claim
A technology can be potentially relevant to a contaminant family without every product carrying the required certified reduction claim.
Learn how claims are verified →Profile counts only These counts summarize the published technology record. They are not removal percentages, performance ratings, or recommendations for your water.
How it worksMechanism describes the treatment process. Actual performance depends on the product, water chemistry, flow, maintenance, and certified claim.
Water is forced under domestic line pressure across a dense semi-permeable polyamide thin-film composite (TFC) membrane. Contaminants larger than water molecules are rejected and flushed to the drain line, producing high-purity permeate water.
Potentially relevant contaminant families“Potentially relevant” means the mechanism may address members of the family. It does not mean every compound is reduced or that a specific product is certified for it.
Known limitations and trade-offs
- Discharges 1 to 3 gallons of brine wastewater for every gallon of purified water produced
- Removes beneficial healthy dietary minerals (calcium and magnesium); often paired with a remineralization post-filter
- Requires adequate household line pressure (minimum 40–50 PSI) or an electric booster pump
- Membrane pores can be fouled by high chlorine or sediment; requires carbon pre-filtration
Installation
Maintenance requirements
- 1
Pre-sediment and carbon blocks: Replace every 6 to 12 months
- 2
RO membrane cartridge: Replace every 24 to 36 months
- 3
Post-carbon remineralizer: Replace every 12 months
Certification and claim verificationA certification standard defines a category of testing. The product listing must also name the contaminant-specific reduction claim you need.
NSF/ANSI 58
Reverse Osmosis Drinking Water Treatment Systems
The benchmark standard for residential point-of-use reverse osmosis units. Evaluates membrane TDS reduction, recovery rating, structural burst pressure, and individual chemical reduction claims.
Verify that the specific claim (e.g., PFOA/PFOS or arsenic) is explicitly tested, as standard 58 allows optional claim certifications.
Products using this technologyThese are catalog products classified under this technology. Classification is not proof that a model carries every claim described above.
Countertop System
AquaTru Classic Countertop Reverse-Osmosis Purifier (AT2000)
A no-installation reverse-osmosis option for renters: certified for lead, fluoride, arsenic V and nitrate (NSF/ANSI 58) and PFOA/PFOS (NSF/ANSI 53).
Under-Sink Filter
Waterdrop G3P600 Tankless Reverse-Osmosis System
Certified PFOA/PFOS (NSF/ANSI 53), lead and fluoride (NSF/ANSI 58) reduction at one kitchen tap, for less than the G3P800.
Under-Sink Filter
Under-Sink Reverse-Osmosis System
Best when PFAS, lead, arsenic, nitrate, or fluoride is detected and you want the broadest reduction at a single tap.
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Sources and methodology
This page uses PurityMap’s governed treatment-technology, certification, and product records. It does not infer treatment need from the technology itself; need begins with a documented local finding or household test.
How PurityMap evaluates treatment relevance →