#ad · Plumbing Picks is reader-supported. As an Amazon Associate we may earn from qualifying purchases at no extra cost to you. Prices are set by Amazon.
Quick answer: Both make extremely pure water — the difference is how you live with it. Reverse osmosis is plumbed under your sink and gives purified water on demand from a dedicated faucet, so it’s the better everyday choice for most households. A distiller is a countertop appliance that boils water and re-condenses it in batches — slower and it uses electricity, but it needs no plumbing, it’s portable, and the boil step kills bacteria, which makes it the pick for renters, no-install situations, CPAP users, and anyone who wants the most contaminant-free water possible regardless of speed.
Short version: Most homes → reverse osmosis (convenience + volume). No-install / portable / pathogen-kill / lab-grade → distiller.
⭐ A PLUMBER’S TOP PICK
Want purified water on demand for the whole household? An under-sink RO system is the everyday pick for most homes — see our tested favorites: Best Under-Sink Reverse Osmosis Systems →
No-install, portable, or need the most contaminant-free water (CPAP, lab use, sensitive health)? A countertop distiller wins: Best Water Distillers for Home Use →
Why trust these picks? How we test & choose →
How each one actually works
Reverse osmosis (RO): household water pressure pushes water through a semipermeable membrane that blocks the large majority of dissolved solids — heavy metals (lead, arsenic), fluoride, nitrates, sodium, PFAS, and most of the total dissolved solids (TDS). It’s a multi-stage cartridge system (sediment → carbon → membrane → polish), usually mounted under the sink with a small storage tank and its own faucet. Removes roughly 90–99% of TDS. It does not disinfect — the membrane physically blocks most microbes but RO is not a substitute for boiling or UV on water of unknown bacterial safety.
Distillation: the unit boils water to steam, leaves the non-volatile junk behind in the boiling chamber, then condenses the steam back into pure water. Because nearly everything that matters is non-volatile (minerals, metals, salts, fluoride) it’s caught — and the boil step kills bacteria and pathogens. A post-condensation carbon filter handles the few volatile compounds (some VOCs) that can otherwise carry over. Countertop units make water in batches at roughly 4–6 hours per gallon and use electricity to do it.
Reverse osmosis vs. water distiller: side by side
| Reverse Osmosis | Water Distiller | |
|---|---|---|
| What it removes | Most dissolved solids, metals, fluoride, nitrates, PFAS | Virtually all non-volatiles + kills bacteria (with post-carbon for VOCs) |
| Speed / output | On demand (tank refills continuously) | Batch, ~4–6 hrs/gal |
| Install | Under-sink plumbing + dedicated faucet | None — countertop, plug-in |
| Energy | None (uses water pressure) | Uses electricity to boil |
| Water waste | Some brine/reject (~1:1 modern to 3–4:1 older) | None (but boil energy) |
| Minerals / taste | Strips minerals (often add a remineralizer) | Strips minerals (flat taste; some aerate) |
| Best for | Daily volume, whole-household drinking/cooking | Renters, portability, CPAP, pathogen-kill, lab-grade |
| Typical cost | $150–$400 system + filters | $100–$400 countertop + electricity |
| Maintenance | Filter + membrane changes | Descale chamber, replace carbon pods |
Which should you choose? (by situation)
- You own your home and want purified water every day without thinking about it → RO. Plumb it once, get a faucet of clean water, refill is automatic.
- You rent or can’t drill the sink / want to take it with you → distiller. No install, unplug and move it.
- You’re on a private well with possible bacteria → the distiller’s boil step is a real advantage (still get the well tested and treat bacterial wells properly).
- CPAP machine → distilled water is the standard recommendation; a distiller makes it at home for pennies vs buying jugs. See our best water distiller for CPAP pick.
- High daily volume (big family, cooking) → RO keeps up; a batch distiller may not.
- You want the single most contaminant-free water and don’t mind waiting → distiller (then a pinch of minerals or a remineralizing pitcher for taste).
A plumber’s honest take
Neither is “better” — they solve the same problem (near-pure water) for different lives. In a house I own, I’d plumb RO under the kitchen sink and forget about it. In an apartment, or for someone who just wants the cleanest possible water with zero install, the distiller wins. Two honest cautions: (1) both strip the minerals that make water taste like something — if your water tastes flat, that’s why, and a remineralizer fixes it; (2) “purest” isn’t the same as “safest from bacteria” — RO blocks but doesn’t kill, so on water of unknown microbial quality, distillation (or adding UV) is the safer call.
Product picks
Reverse osmosis (under-sink) — see the full best under-sink reverse osmosis system roundup:
- iSpring RCC7AK (6-stage + alkaline remineralization) (#ad · price set by Amazon)
- Waterdrop G3P600 (tankless) (#ad · price set by Amazon)
- Express Water RO5DX (budget 5-stage) (#ad · price set by Amazon)
Water distiller (countertop) — see the full best water distiller for home use roundup:
- Megahome (White, Glass Collection) (#ad · price set by Amazon)
- H2O Labs 300SS (#ad · price set by Amazon)
- VEVOR 1.1-gallon (budget) (#ad · price set by Amazon)
Still weighing whole-house options? Compare a reverse osmosis system vs. a water softener, or see our best whole-house water filter guide.
Frequently asked questions
Is distilled or RO water healthier?
Both remove contaminants and both remove minerals. The health impact of mineral loss is minor for most diets — remineralize if you prefer the taste.
Does reverse osmosis remove bacteria?
It blocks most microbes physically, but it’s not a disinfectant. Don’t rely on RO alone for microbially unsafe water.
Is a distiller cheaper to run than RO?
It’s close. A distiller has no membrane but uses electricity each batch; RO uses water pressure but wastes some water and needs filter/membrane changes. Net cost depends on usage.
Can I drink distilled or RO water every day?
Yes — the flat taste is mineral loss, not a safety issue.
Which is better for a private well?
Distillation’s boil step kills pathogens; test the well and treat bacteria properly regardless.
Fix the 12 Most Common Plumbing Problems Yourself — Free Plumber’s Handbook — including how to tell if your water heater is about to fail
Step-by-step fixes for the 12 most common problems — and exactly when to call a pro. Free and instant, from a licensed plumber. Save hundreds on calls you didn’t need.