Types of water filters: which one is right for you?
Pitcher, faucet, under-sink, reverse osmosis, whole-house, gravity — six types, and the right one depends on what's in your water and where you want to treat it. Here's each one compared honestly, with real cost per gallon and what it actually removes.
The 3 things that decide it
All six types, compared
Each type wins at something — there's no single best. Find the row that matches what you need.
| Type | What it removes | Cost / gallon | Typical price | Install | Filter changes |
|---|---|---|---|---|---|
| PITCHER Cheapest to start | Taste & chlorine; a few certified for lead | ~46¢ | $17–$52 | Fill and pour. No installation. | ~6× |
| FAUCET-MOUNT Cheapest lead-certified | Chlorine, and lead on many certified models | ~24¢ | $24–$30 | Screws onto the faucet. No tools. | ~4× |
| UNDER-SINK Best cost per gallon | Lead, chlorine, VOCs, cysts — often PFAS | ~1¢ | $27–$397 | Mounts under the sink; connects to the cold line. Basic DIY. | ~1–2× |
| REVERSE OSMOSIS Most thorough removal | All of that PLUS fluoride, arsenic, nitrate & dissolved solids | ~23¢ | $40–$479 | Under-sink system with a dedicated faucet and storage tank. | ~1× (multi-stage) |
| WHOLE-HOUSE Treats every tap | Chlorine, sediment & taste — at every tap | ~1¢ | $21–$1,375 | Point-of-entry install on the main line. Usually a plumber. | ~1× |
| GRAVITY No plumbing, lowest cost/gal | Varies by cartridge — always verify certification | ~34¢ | $28–$375 | Countertop tank; no plumbing or power. | every 1–2 yrs |
Cost per gallon and price ranges are computed from the certified models in our database (10th–90th percentile of priced models). Whole-house cost/gallon runs lower on a different basis.
Each type, honestly
Filter pitcher
A fill-and-pour jug with a replaceable carbon cartridge. The cheapest way to start — but certification varies enormously.
- Cheapest to buy; no installation
- Perfect for renters and small households
- A few are certified to the health standard for lead
- Most are aesthetic-only (NSF 42) — taste, not lead/PFAS
- Highest cost per gallon after pitchers and fridge filters
- Slow; small cartridges clog and need frequent swaps
Best for: Renters and anyone who wants a cheap start — but check for NSF/ANSI 53 if you need lead reduction.
Faucet-mount filter
A small unit that screws directly onto your existing faucet, with a switch for filtered or unfiltered water.
- Cheap and installs in seconds — no plumbing
- Several are certified to the health standard for lead
- Switch between filtered and tap water
- Doesn’t fit every faucet
- Slows your flow; bulky on the tap
- Frequent cartridge changes
Best for: Renters who want real lead reduction without any plumbing.
Under-sink filter
A carbon-based cartridge (or set of stages) plumbed under your kitchen sink that filters the cold drinking-water line.
- Lowest cost per gallon of any point-of-use filter
- Certified for the most health contaminants (lead, VOCs, cysts, often PFAS)
- Out of sight; strong flow with no separate tank
- Needs a cabinet and a simple plumbing connection
- Does NOT remove fluoride, arsenic, or nitrate — only RO does
- Not for renters who can’t modify plumbing
Best for: Homeowners who want the best all-round value for lead, chlorine, and VOCs at the kitchen tap.
Reverse osmosis system
A multi-stage under-sink system that forces water through a semi-permeable membrane, removing the widest range of contaminants — including dissolved ones carbon can’t touch.
- The most thorough removal — the only common type that takes out fluoride, arsenic, nitrate, and dissolved solids
- Health-standard certified (NSF/ANSI 58)
- Great for well water and problem tap water
- Wastes some water (a few gallons per gallon produced)
- Removes beneficial minerals too; slower flow from a storage tank
- Higher upfront cost and more filter stages to replace
Best for: Anyone whose water has fluoride, arsenic, nitrate, or heavy dissolved-solids — or who simply wants the most thorough option.
Whole-house system
A point-of-entry system installed on your main water line, treating every tap and shower in the house.
- Treats every tap and shower — not just drinking water
- Great for chlorine, sediment, and taste at high volume
- Protects skin, hair, and appliances
- Few are certified for health contaminants like lead — pair with an under-sink filter for drinking
- Professional install on the main line
- Higher upfront cost
Best for: Homeowners bothered by chlorine/sediment throughout the house — paired with an under-sink filter for drinking water.
Gravity filter
A stand-alone countertop tank (like a Berkey) that filters by gravity — no plumbing and no power.
- Lowest cost per gallon of anything; long cartridge life
- No plumbing or power — great off-grid and for emergencies
- Portable
- Very few are NSF/WQA certified — certification is the #1 thing to check
- Manual refilling; takes counter space
- Slow gravity flow
Best for: Off-grid, emergency prep, or anyone wanting the cheapest long-run cost — but verify certification first.
Still not sure?
It really does come down to your water. Look up the contaminants in your system, then pick whichever type is certified to remove them at the lowest cost per gallon.