Kohler Aquifer+ Two-Stage (K-29638) review
By Daryna Klochko · Published · Specs checked Oct 15, 2026 · 
Scores 9.25/10, tied for 26th of the 32 under-sink filters we track. At $356.25 it costs 1.8 times the category median of $199.50. IAPMO lists it for Chlorine, Chloramine, Lead, Cysts, VOCs, PFOA/PFOS, one of 29 under-sink filters out of 32 with a certifier listing for a health claim. Its 90-day return window is 3 times the 30-day category median.
A long warranty: 5 years, tied for the longest stated among the 32 under-sink filters
Running costs matter: about $390 a year in cartridges, 2.3 times the category median
- Price
- $356.25
- Certified for
- Lead · Cysts · VOCs +4
- Flow
- 0.85 gpm
- Cartridge life
- 389 gal
- Cost per year
- $390
- Warranty
- 5 years limited
Certification
Listed by IAPMO under NSF/ANSI 42 · 53 · 401 · P473 · P231 for Chlorine, Chloramine, Lead, Cysts, VOCs, PFOA/PFOS, checked Oct 15, 2026. Search the IAPMO listings
- Chlorine
- Chloramine
- Lead
- Cysts
- VOCs
- PFOA/PFOS
The contaminants or other substances removed or reduced by this water treatment device are not necessarily in your water. Listing checked on Oct 15, 2026. What a listing means and what it doesn't
Specs and sources
Checked Oct 15, 2026 · source under each valueFiltration
Cartridges and install
Buying
Warranty, returns and shipping
90 days from shipment (kohler.com, new and saleable).
Warranty: 5 years limited. Returns: 90 days from shipment (kohler.com, new and saleable). Shipping: not stated by the brand. Source: Kohler data sheet, checked Oct 15, 2026.
Source: Kohler data sheet, checked Oct 15, 2026.
Compared with similar under-sink filters
All 32 under-sink filters →| Model | Price | Certified for | Cost per year | Warranty | Score | Where to buy |
|---|---|---|---|---|---|---|
| 3M Aqua-Pure 3MDW301-F Under Sink System with Faucet | $294 | Lead · Cysts +8 | $278 | 1 year | 9.25/10 | See specs → |
| Kohler Aquifer Double Cartridge (K-77686) | $300 | Lead · Cysts +5 | $300 | 5 years limited | 9.25/10 | Check price → |
| Aquasana Claryum 3-Stage (AQ-6300) | $349.99 | Lead · Cysts +5 | $168 | 1 year limited | 9.75/10 | Check price → |
| Kohler Aquifer+ Two-Stage (K-29638)THIS MODEL | $356.25 | Lead · Cysts +5 | $390 | 5 years limited | 9.25/10 | Check price → |
| Everpure EF-1500 Full Flow Drinking Water System | $367.93 | Lead · Cysts +2 | $139 | 1 year | 9.75/10 | See specs → |
What owners say
Checked Oct 15, 2026Reviews only on the brand's own site. In our score this is 1.75 of 2 points. How we score
Store ratings change over time; the date shows when we checked.