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Our Verdict (Best for)
The newly updated Waterdrop A1 is a sturdy, well-built system that’s easy to set up and use, with very low wastewater. It earns our recommendation for the #1 countertop RO for those who want hot and cold water on demand (although the hot water could be a little hotter). The system offers a large and responsive touch screen with plenty of features (e.g. 6 water temp, 4 volume presets, TDS monitor, night & vacation modes). In our testing, the Waterdrop A1 removed almost all contaminants to below detection levels, and it had the highest TDS removal of all the RO systems we tested. Our filtered water also tasted and smelled great. Cons: Contaminant reduction testing against NSF standards? Yes, but no actual certifications. Also, the unit is tall and heavy, taking up lots of counter space, and it’s noisy, especially in cooling mode.
2025 Waterdrop A1 Update
When we first reviewed the Waterdrop A1, our lab testing detected an alarming amount of methylene chloride (11.87 ppb) in our filtered water, more than twice the OEHHA’s 4 ppb health goal for drinking water set to prevent liver problems and carcinogenic effects, and also more than twice the EPA’s 5 ppb legal limit for tap water. We also detected 0.71 ppb of xylene in our water, but at least that was well below health guidelines and legal limits. Still, we immediately stopped our testing and pointed out the potential leaching to Waterdrop back in 2024. To their credit, they subsequently pulled the system from the shelves to do an investigation and a redesign. The newly redesigned Waterdrop A1 is now available, and we recently conducted lab tests on this new version.
The Waterdrop A1 is a countertop reverse osmosis system that can provide both hot and cold water and that doesn’t require a plumbing connection. It’s designed for use as a drinking water filter and can purify both tap water and properly disinfected well water.
As usual, we’ve tested the system with our own hands:
- Hands-on experience: We installed/assembled, used, and maintained it.
- Filtration effectiveness: We sent an unfiltered and a filtered tap water sample to a professional lab for analysis in order to determine real-life contaminant reduction capabilities. Plus, we checked for NSF certifications and other test data.
- More testing: We performed a taste & odor test, a filtration speed test, water temperature tests, and a wastewater test.
- All other product aspects: We considered initial + long-term cost, product warranties, additional features, frequent customer complaints, etc.
Contents
Overall Rating: /5.00
Filtration: /5.00
Usability: /5.00
Costs: /5.00
| Type: | Countertop Reverse Osmosis System With Hot & Cold Water |
| Price (Mar 4, 2025, w/o Short-Term Sales): | $649 (Use Code A1BOS for 3% Off on Top of Most Waterdrop Sales!) |
| Estimated Yearly Cost (Aug 5, 2024): | ~$130 (Save 5% With Filter Subscription) |
(Use Code A1BOS for 3% Off on Top of Most Waterdrop Sales!)
Overall Rating: /5.00
What We Like Most
- Achieved excellent results in our lab testing for contaminant reduction.
- Highest TDS removal rate of all RO systems we tested.
- Our filtered water was taste and odor-free.
- Tested against NSF standards 42, 53, and 58 for the reduction of 22 contaminants.
- Low wastewater.
- Produces hot and cold RO water on demand.
- Sturdy and well built, easy to set up with clear instructions and a video, and easy to prime and use.
- Large and responsive touchscreen with multiple temperature selections, water volume options, TDS monitoring, night & vacation modes, QR codes to access manual and service, and more.
- Easy filter replacements also thanks to filter life indicator, with a QR code for easy reordering.
- Additional features: Optional child safety for hot water, cooling can be turned off to save energy and reduce noise, boiling point correction, dispensing light, water change and shortage reminders.
- Average upfront cost for its class and below-average annual maintenance fees.
What We Don’t Like
- A tiny amount of xylenes were detected in our filtered water (370x lower than the strictest health guideline).
- No actual NSF certifications for contaminant reduction.
- Tall, deep, and heavy; takes up a lot of counter space and may be hard to access the water feed tank.
- Hot water could be a little hotter.
- Noisy (especially the cooling mode).
- Night mode requires you to program a start and end time.
- 3rd-party customer complaints about malfunctioning units, leaking, unresponsive displays, hot not being hot and cold not cold, but these may have been addressed with the updated system.
Video: Sara Reviews the Waterdrop A1
Video Chapters
- 00:00 – Intro
- 00:35 – What Happened So Far
- 02:27 – The New Waterdrop A1
- 02:59 – Does It Still Leach?
- 03:28 – Contaminant Reduction
- 04:22 – Updated Google Sheet
- 04:47 – NSF Standards
- 05:17 – Taste & Odor
- 05:22 – Filter Process
- 06:05 – Usability
- 10:09 – Wastewater
- 10:23 – User Complaints
- 10:52 – Costs
- 11:24 – Summary
- 12:30 – Outro
How the Waterdrop A1 Compares to…
25 Other Countertop Water Filters
In this video, Sara covers our top picks among the 26 countertop water filters we’ve tested. The updated Waterdrop A1 model wasn’t included because too new. Still, it’s part of our countertop water filter comparison sheet.
Video Chapters + Comparison Sheet
- Link to Comparison Sheet
- 00:00 – Intro
- 00:33 – Our 26 Countertop Filters
- 03:14 – How We Tested & Rated
- 09:11 – Best Overall (AquaTru Classic)
- 14:33 – Best RO Budget Pick (AquaTru Carafe)
- 16:50 – Honorable Mention (Bluevua RO100ROPOT)
- 18:27 – Best “Regular” Filters (Aquasana CWM & ZeroWater)
- 27:47 – Best “Regular” Budget Pick (Waterdrop ED04)
- 33:04 – Summary
9 Other Countertop Reverse Osmosis Systems
In this video, Sara covers our top picks among the 10 countertop reverse osmosis systems we’ve tested. The updated Waterdrop A1 model wasn’t included because too new. Still, it’s part of our countertop RO comparison sheet.
Video Chapters + Comparison Sheet
- Link to Comparison Sheet
- 00:00 – Intro
- 00:27 – Our 10 Countertop ROs
- 01:15 – How We Tested & Rated
- 04:23 – System Setup & Filter Priming
- 04:38 – Sampling Process
- 05:41 – Lab Testing Disclaimer
- 06:07 – Taste & Odor Test
- 06:28 – Speed Test
- 07:05 – Pure-to-Drain Ratio Test
- 07:31 – Best Overall (AquaTru Classic)
- 10:49 – Best Budget Pick (AquaTru Carafe)
- 12:30 – Best for Hot Water (NU Aqua & APEC)
- 15:30 – Honorable Mention (Bluevua)
- 16:00 – Summary
Full Analysis of the Waterdrop A1
Filtration: /5.00
1. Lab Results: /5.00
Remember that our before vs after lab comparison is not an exact science. It’s informational and subject to variability, inaccuracies, and interferences caused by natural fluctuations in water quality, accidental contamination, human error, instrumentation issues, and more. Furthermore, our lab-testing is limited to those contaminants present in our water supplies and at their respective concentrations. As such, it can only give us a general idea for how effective a certain water treatment product might be.
Lab Results Chart
| Potentially Harmful | Aesthetic Issues | Feed Water Level | Filtered Water Level | Reduction Rate | |
| Water Disinfectants | |||||
| Chlorine (mg/L) | ✖ | ✖ | 0.98 | 0 | 100% |
| Disinfection Byproducts | |||||
| Bromodichloromethane (µg/l) | ✖ | 4.64 | 0 | 100% | |
| Bromoform (µg/l) | ✖ | 4.32 | 0 | 100% | |
| Dibromochloromethane (µg/l) | ✖ | 7.94 | 0 | 100% | |
| Chloroform (µg/l) | ✖ | 1.61 | 0 | 100% | |
| Metals | |||||
| Copper (mg/L) | ✖ | ✖ | 0.11 | 0 | 100% |
| Iron (mg/L) | ✖ | 0.02 | 0 | 100% | |
| Barium (mg/L) | ✖ | 0.04 | 0 | 100% | |
| Boron (mg/L) | ✖ | 0.06 | 0.03 | 50% | |
| Zinc (mg/L) | ✖ | 0.01 | 0 | 100% | |
| Strontium (mg/L) | ✖ | 0.40 | 0 | 100% | |
| Salts | |||||
| Nitrate (N) (mg/L) | ✖ | 1.93 | 0 | 100% | |
| Fluoride (mg/L) | ✖ | 0.69 | <0.1 | Anywhere Between 86% and 99% | |
| Other | |||||
| Uranium (µg/L) | ✖ | 1 | 0 | 100% | |
| RO Salt Rejection | |||||
| TDS (mg/L) | ✖ | 329.4 | 6.6 | 98% | |
| Impurities NOT Detected in Unfiltered Tap Water Sample | |||||
| m+p Xylenes (µg/l) | ✖ | 0 | 1.32 | ||
| Explanation: | |||||
| Full Removal | |||||
| Considerable Reduction | |||||
| Concentration More Than Double of Unfiltered Water Sample | |||||
| Potential Leaching Reached or Exceeded the Strictest Public Health Guideline We Could Find | |||||
*100% means reduction to below the minimum detection level. To learn more about our testing procedures check our editorial guidelines.
Link to Filtered Water Report
Link to Unfiltered Water Report
Usability: /5.00
Costs: /5.00
Please note: This page is still a work in progress. Additional content and details will be added shortly – stay tuned!
About the Author(s)
Sara has been a lifelong home-improvement fan (she’s been hooked on This Old House since she was five) and taught herself any project she didn’t already know by watching YouTube tutorials. She is also an award-winning filmmaker. Armed with this skillset, Sara installs, primes, samples, uses, and maintains nearly every point-of-use water treatment systems we test – then brings her results to life on camera for our YouTube channel.
Raoul has a background in mechanical engineering and has been writing about home water treatment since 2015. He designs our product review processes, analyzes the results, and ties everything together. As editor-in-chief, he tries hard to keep the whole operation running smoothly behind the scenes.