H2O Insider

Reverse Osmosis vs Distilled Water

Reverse osmosis vs distilled water: both remove 99%+ of contaminants. RO costs ~$0.06/gallon. Distillation costs ~$0.28/gallon. Lab data shows when each technology wins.

Reverse Osmosis vs Distilled Water
Illustrative photo of this product type, not the specific product reviewed.
Option A

Waterdrop G3P800 Tankless RO

$649

Waterdrop G3P800 Tankless RO
Option B

APEC Water ROES-50

$235

APEC Water ROES-50

Quick Verdict

RO wins for home drinking water — faster, dramatically cheaper per gallon, and equally effective on every health contaminant that matters. Distillation is the better choice only for laboratory or medical applications that require no membrane maintenance.

RO vs Distilled: Same Purity, Very Different Economics

Reverse osmosis and distillation both produce water with 95–99%+ removal of dissolved contaminants — the end result in a glass is remarkably similar. The difference is in how you get there. RO uses a pressurized membrane and produces water continuously at $0.05–$0.08/gallon. Distillation boils water and collects purified steam at $0.25–$0.35/ gallon in electricity costs, producing about 1 gallon every 3–4 hours.

For home use: RO wins decisively on economics. A 75 GPD (gallons per day) RO system provides continuous filtered water for a family of 4 at a fraction of distillation's operating cost. Distillation has legitimate specialty applications — CPAP humidifiers, laboratory equipment, and situations requiring VOC removal that RO cannot achieve. For drinking water: the choice is RO.

Technical Comparison: Where Each Technology Wins

FactorReverse OsmosisDistillationWinner
TDS removal83–90%98–99%Distillation
Lead removal99%+99%+Tie
PFAS removal95%+>99%Tie (both effective)
Nitrate removal88–92%99%+Distillation
VOC removalPartial (50–80%)95%+ (most VOCs)Distillation
Production speed75–400 GPD continuous~1 gallon/4 hrsRO
Operating cost$0.05–$0.08/gallon$0.25–$0.35/gallonRO
System cost$150–$400 installed$150–$500 countertopSimilar
MaintenanceAnnual filter changesClean after every batchRO
NSF certificationNSF 58 (full system)Limited optionsRO
Best forHome drinking waterMedical equipment, lab useDepends on use

The 5-Year Cost of Each Approach

Under-Sink RO (iSpring RCC7AK)

Setup: $249 + $200 installation = $449
Annual: $65 filters + ~$15 electricity
5-year total: $449 + ($80 × 5) = $849
No certification listing found (Sept 2026), 3.2-gal tank, family of 4 use

Countertop RO (AquaTru)

Setup: $349 (no install)
Annual: $100 filters
5-year total: $349 + ($100 × 5) = $849
Model match to IAPMO NSF 58 listing unconfirmed, portable, 1-gal tank

Countertop Distiller (Mophorn)

Setup: $150
Annual: $200 electricity + $30 cleaning supplies
5-year total: $150 + ($230 × 5) = $1,300
1 gal/4hrs — may require multiple cycles for family

Bottom Line

For home drinking water: buy an NSF 58-listed RO system. RO delivers purity close to distilled water at lower operating cost with continuous supply. The Waterdrop G3P800 ($649) is listed: IAPMO lists it under NSF/ANSI 58 for lead, fluoride and TDS, and under NSF/ANSI 53 for PFOA/PFOS. IAPMO lists AquaTru countertop RO systems under NSF 58, but the match to the model we reviewed is pending model-number confirmation. We found no NSF, IAPMO or WQA certification listing for the iSpring RCC7 (checked September 2026). Use distillation only for CPAP humidifiers, laboratory equipment, reef tanks, or applications requiring VOC removal that RO cannot reliably provide.

Total Cost of Ownership

PeriodWaterdrop G3P800 Tankless ROAPEC Water ROES-50
1 year$769$300
3 years$1,009$430
5 years$1,249$560
10 years$1,849$885

Frequently Asked Questions