Doulton QT Under Counter System (Ultracarb) review
By Daryna Klochko · Published · Specs checked Oct 15, 2026 · 
Scores 9.5/10, tied for 17th of the 32 under-sink filters we track. At $119.99 it costs less than the category median of $199.50. Doulton also claims VOCs, which is not in the listing. Its 3-year warranty is longer than the 1-year category median.
A lower budget: $119.99, in the cheapest quarter of the 32 under-sink filters
- Price
- $119.99
- Certified for
- Lead · Cysts · Microplastics +1
- Flow
- 0.5 gpm
- Cartridge life
- 600 gal
- Cost per year
- $42
- Warranty
- 3 years (limited)
Certification
Listed by NSF under NSF/ANSI 42 · 53 · 401 for Chlorine, Lead, Cysts, Microplastics, checked Oct 15, 2026. Doulton also claims 1 more substance that is not in the listing. Search the NSF listings
- Chlorine
- Lead
- Cysts
- Microplastics
Doulton also claims VOCs: brand claims, not in a certifier listing.
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
3 years limited on parts (not the cartridge).
14 days, unused; sale items final.
Warranty: 3 years limited on parts (not the cartridge). Returns: 14 days, unused; sale items final. Shipping: not stated by the brand. Source: britishwaterfilter.com, checked Oct 15, 2026.
Source: britishwaterfilter.com, 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 |
|---|---|---|---|---|---|---|
| A. O. Smith AO-US-200 2-Stage Under Sink Filter | $111.11 | Lead · Cysts +7 | $168 | 1 year limited | 9.75/10 | Check price → |
| Doulton QT Under Counter System (Ultracarb)THIS MODEL | $119.99 | Lead · Cysts +2 | $42 | 3 years (limited) | 9.5/10 | Check price → |
| A. O. Smith AO-MF-ADV Advanced Direct Connect Faucet Filter | $119.99 | Lead · Cysts +5 | $187 | 1 year limited | 9.75/10 | Check price → |
| Frizzlife SK99 3-Stage Under Sink Water Filter | $125.99 | Lead · Cysts +1 | $95 | 1 year | 10/10 | Check price → |
| Epic Water Filters Smart Shield Under Sink | $129 | Lead · Cysts +3 | $115 | 3 years limited | 9.75/10 | Check price → |