Osma pitcher on a kitchen counter
NSF/ANSI 401 certified
— Osma · Filtration

Reverse-osmosis purity.
Pitcher simplicity.

NSF/ANSI 401 certified. Removes lead, PFAS, microplastics, and chlorine — while keeping the magnesium and calcium your body wants. Fits in your fridge. No plumbing.

See the pitcher →
NSF 42Aesthetic
NSF 53Health
NSF 401Emerging
BPA-freeMaterials
— What it removes

Three things most pitchers miss.

Independent lab testing against NSF/ANSI 53 and 401 protocols. Numbers below are from sample WT-2026-0314-A.

Lead (Pb)
99.1%

From corroded service lines and pre-1986 solder. Tested per NSF/ANSI 53.

PFAS / forever chemicals
<0.5 ng/L

PFOA and PFOS reduced below detection limits. NSF/ANSI 401 + P473.

Microplastics
0.5 µm

Carbon block filtration retains particles down to 0.5 microns.

— Where Osma sits

Between a pitcher and a plumber.

Most pitchers improve taste. Reverse-osmosis systems remove everything — including the minerals you want, with the wastewater and the plumbing bill that come with it. Osma is built for the gap in the middle.

See the comparison →
BASIC PITCHER Improves taste OSMA RO-grade, no plumbing UNDER-SINK RO $400+ install $30–60 $79 $400+ taste only lead · PFAS · fluoride strips minerals
— Third-party verified

We don’t grade our own homework.

Every Osma is engineered to NSF/ANSI 53 and 401 protocols and verified by an independent lab. Methodology is documented; certification publishing on a timeline this year.

Test protocol · NSF/ANSI 53 + 401 + P473
Sample type · Production-line unit
Test frequency · Quarterly + annual full retest
See the full methodology →
Filtered water pouring into a glass
4.8
★★★★★
Based on 1,247 verified reviews
— What customers say

From people who tested it themselves.

★★★★★

"The fluoride test strips don't lie."

I bought test strips before and after. Tap water came in around 0.7 ppm. After filtering: undetectable. Three months in, zero complaints.

Sarah M. · Portland, OR Verified
★★★★

"Slower than my old Brita. Worth it."

Takes ~11 minutes to fill. Plan ahead and it's a non-issue. The taste difference for tea and coffee is the part I didn't expect.

Jennifer L. · Boston, MA Verified
★★★★★

"Switched after the EPA stop-sale."

Had a Big Berkey for six years. After the 2024 EPA action I started looking. NSF certs, fluoride confirmed by my own strips, fits in the fridge. Smaller than Berkey, which is fine.

Mike R. · Austin, TX Verified
— Free

Get our independent lab report.

We email it once. Then quarterly updates on standards changes — PFAS, lead, what's new in regulation. Unsubscribe in one click.