On the deciding criteria
Warranty & Support10
Contaminant Reduction8
Value5
Why it sits here
- Ahead of the WaterChef U8500 by 0.10, with no single criterion a full point ahead.
Top rated under sink water filtration systems · ranked by score17 September 2026
The best under sink water filters
The WaterChef U9000 ranks first of 20 under sink water filters we have scored, at 7.3 out of 10. The five on this list cost $86 to $499, and their scores are within 0.96 of each other. Across all 20, scores run from 5.1 to 7.3.
- 20 scored
- 6 brands
- top five within 0.96
- scores 5.1–7.3
- updated 17 September 2026
The top 5 at a glance
How close the under sink water filters are
Every product we scored, placed by overall score. The 5 on this list are in color.
Lower
Mid
Upper
Top 10%
123 5.05.56.06.57.07.5
- 0.96spread across the top 5
- ±0.022 could swap places
- on this list
- the other 15 scored
The 5 best under sink water filters
In order of overall score. Under each: where it wins and loses on the three criteria that separate these 5, and why it sits where it does.
On the deciding criteria
Warranty & Support10
Contaminant Reduction8
Value5
Why it sits here
- Ahead of the Waterdrop UA-5Y by 0.38, led by warranty & support (10 against 1) and contaminant reduction (8 against 7).
On the deciding criteria
Warranty & Support1
Contaminant Reduction7
Value7
Why it sits here
- Ahead of the Express Water StreamLine USC001 by 0.47, led by contaminant reduction (7 against 6) and certification coverage (10 against 9).
- Beats the WaterChef U8500 above it on value (7 against 5) and filter life (8 against 5), and still trails it by 0.38 overall.
On the deciding criteria
Warranty & Support1
Contaminant Reduction6
Value7
Why it sits here
- Level with the Aquasana Claryum 2-Stage below it (0.02 apart), though ahead on value (7 against 4).
- Beats the Waterdrop UA-5Y above it on flow rate (5 against 4), and still trails it by 0.47 overall.
- Wrong for anyone treating a specific contaminant: contaminant reduction scores 6, against 9 for the Aquasana Claryum 2-Stage.
On the deciding criteria
Warranty & Support1
Contaminant Reduction9
Value4
Why it sits here
- Beats the Express Water StreamLine USC001 above it on contaminant reduction (9 against 6) and certification coverage (10 against 9), and still trails it by 0.02 overall.
- Wrong for a tight budget: value scores 4, against 7 for two of these five.
Just outside the five: the Aquasana Claryum 3-Stage, 6th at 6.3, 0.07 behind.
What separates them
Warranty & Support, Contaminant Reduction and Value.
- /10every score
- 10best here
- ▲▼move vs overall
- T-tie
| Overall | Product | Warranty & Support1–10 | Contaminant Reduction6–9 | Value4–7 | 3-criteria rank |
|---|---|---|---|---|---|
| 1 |  WaterChefU9000 |
10 | 8 | 5 | T-1 |
| 2 |  WaterChefU8500 |
10 | 8 | 5 | T-1 ▲1 |
| 3 |  WaterdropUA-5Y |
1 | 7 | 7 | 4 ▼1 |
| 4 |  Express WaterStreamLine USC001 |
1 | 6 | 7 | 5 ▼1 |
| 5 |  AquasanaClaryum 2-Stage |
1 | 9 | 4 | 3 ▲2 |
Ranked on these three alone, the order changes most for the Aquasana Claryum 2-Stage (5th overall, 3rd on those three criteria) and the Waterdrop UA-5Y (3rd overall, 4th on those three criteria).
3-criteria score: the weighted average of these three alone, and where it places each of the 5.
Where these five fall short
What holds across the list rather than for one product.
- CertificationAll 5 carry a health-effects certification: NSF/ANSI 53, 58, 401 or P473.
- WarrantySplit 3 at 1-year, 2 at lifetime.
- PriceCheapest is the Express Water StreamLine USC001 at $86: 0.94 behind first place, at 17% of its price.
- Brands4 brands across the 5; WaterChef has 2. No cap on any brand.
Best under sink water filters under $100
The same scores, cut by price. Rank is against all 20.
What changed since the last edition
First edition - nothing to compare yet. From the next edition this section lists every move, with its cause:
- a new product
- a price change
- new owner reports
- a change to how we score
Under sink water filters: common questions
What is the best under sink water filter?
On our scores, the WaterChef U9000: 7.3 overall, first of 20 we scored on 17 September 2026. The WaterChef U8500 is 0.10 behind at $432.
What are the top rated under sink water filtration systems?
On our scores: the WaterChef U9000 (7.3), the WaterChef U8500 (7.2) and the Waterdrop UA-5Y (6.8). We score 20 under sink water filters in all, and the rest of the order is on this page.
Is the WaterChef U9000 better than the WaterChef U8500?
On our scores, yes: 7.3 overall against 7.2. They cost $499 and $432.
What are the best under sink water filters under $100?
The Express Water StreamLine USC001 at $86, 4th of 20 overall. Next are the Waterdrop 10UA ($59, 9th) and the Aquasure Fortitude Compact Siliphos ($60, 18th).
How much does an under sink water filter cost?
The 20 under sink water filters we score list at $50 to $499 at the maker's own store, and half cost $161 or less. The five on this list run $86 to $499.
Which of these under sink water filters has the longest warranty?
Two carry a lifetime warranty: the WaterChef U9000 and the WaterChef U8500.
Which of these under sink water filters is best at contaminant reduction?
The Aquasana Claryum 2-Stage scores 9 on contaminant reduction, the highest of the five. It is 5th overall at $250.
Which of these under sink water filters has the best flow rate?
Four score 5 on flow rate, the highest of the five: the WaterChef U9000 (1st overall), the WaterChef U8500 (2nd overall), the Express Water StreamLine USC001 (4th overall) and the Aquasana Claryum 2-Stage (5th overall).
Which of these under sink water filters has the best filter life?
The Waterdrop UA-5Y scores 8 on filter life, the highest of the five. It is 3rd overall at $140.
Which of these under sink water filters is the best built?
Two score 9 on build quality, the highest of the five: the WaterChef U9000 (1st overall) and the WaterChef U8500 (2nd overall).
Which of these under sink water filters is the easiest to install?
Three score 8 on ease of installation, the highest of the five: the Waterdrop UA-5Y (3rd overall), the Express Water StreamLine USC001 (4th overall) and the Aquasana Claryum 2-Stage (5th overall).
Which of these under sink water filters is the best value?
Two score 7 on value, the highest of the five: the Waterdrop UA-5Y (3rd overall) and the Express Water StreamLine USC001 (4th overall).
What is the cheapest under sink water filter on this list?
The Express Water StreamLine USC001 at $86 (4th of 20 overall). The most expensive is the WaterChef U9000 at $499.
Which of these under sink water filters do owners rate highest?
The WaterChef U9000 and the Waterdrop UA-5Y, at 7.0 out of 10 on what owners and independent testers report, the highest of the five. Overall they are 1st and 3rd.
Which brands make the best under sink water filters?
Of the five on this list, WaterChef has two and Waterdrop, Express Water and Aquasana have one each. The top pick is from WaterChef.
How many under sink water filters did you compare?
20, from 6 brands. We list 20 and rank every one.
How is this list ranked?
By the overall score: half our specification score across eight criteria, half what owners and independent testers report across up to five sources. The same number sits on every product page.
When was this list last updated?
This edition is dated 17 September 2026. The list is rebuilt whenever our product data changes, and a new edition goes up once it has been checked. Anything that moved since the last edition is listed on this page with the reason.
Under Sink comparisons
Head-to-heads between brands and products on this list.
Scores calculated 17 September 2026 · 20 products ranked; a product needs at least two independent sources to be ranked · How we score · All rankings