Waterdrop A1 Review: Lab Analysis & Hands-On Testing

Full Analysis of the Waterdrop A1

Filtration: 4.50/5.00

The Waterdrop A1 countertop RO system scored 4.50/5.00 for filtration. How? Most importantly, it achieved excellent results in both our 2024 and 2025 lab tests and the filtered water tasted clean (2024) or much improved compared to tap water (2025) with no odor either year. While the system has no NSF/ANSI-certified contaminants, it is well-covered by third-party testing for contaminant reduction.

1. Lab Results: 5.00/5.00 (2025) & 4.73/5.00 (2024)

In our lab test comparing an unfiltered and a filtered tap water sample, the Waterdrop A1 could remove 13 undesirable impurities and contaminants to below the minimum detection level (so essentially to 100%): chlorine, bromodichloromethane, bromoform, dibromochloromethane, chloroform, copper, barium, strontium, iron, manganese, zinc, nitrate, and uranium.

The following substances remained in our water:

• Boron was reduced by a moderate 50% in 2024 and was completely eliminated in 2025.
• Fluoride was reduced by a minimum of 86% (high) and up to 99% (very high) in 2024. This range indicates some fluoride remained in the water but it was so little that the lab couldn’t quantify precisely how much was left. In our 2025 lab test, we used a different and presumably more precise fluoride detection method and fluoride was completely eliminated.

Finally, TDS decreased by 98% in 2024 and 97% in 2025. While TDS should not be interpreted independently, as it does not override inadequate removal of individual contaminants, ≥95% TDS reduction is very high and shows that the RO membrane works as intended.

Aside from contaminant reduction, we found m+p xylenes in our 2024 filtered water that were not present in the unfiltered water, suggesting potential leaching. At 1.32 ppb, the level was nearly 380x lower than the strictest health guideline of 500 ppb published by the WHO, so not particularly worrisome.

In addition, we detected methylene chloride in our 2025 filtered water that was not present in the unfiltered water, suggesting potential leaching. Though again not ideal, at 0.53 ppb it was still ~7.5x lower than the strictest health guideline of 4 ppb published by the OEHHA.

Lab Results Charts

2. NSF/ANSI Certifications and Other Test Data

The Waterdrop A1 does not have any NSF/ANSI certifications for contaminant reduction. However, it is well-covered by third-party testing for the reduction of several contaminants against NSF/ANSI standards 42, 53, 58, and other non-NSF/ANSI standards – we counted 22 in total.

Reported reduction rates include:

• Dissociate chlorine residue (>99.50%)
• Chloramine (97.22%)
• Chloroform (>99.94%)
• Fluoride (99.53%)
• Nitrate (99.38%)
• TDS (95.34%)
• Copper (>99.84%)
• Arsenic (91.67%)
• Lead (>99.69%)
• Chromium 6 (>97.38%)
• PFOA (>99.80%)
• PFOS (>99.10%)
• Total Coliforms (>99.99%)
• Several antibiotics (99.93-99.94%+)

Reduction rates are per Waterdrop A1’s performance data sheet and third-party test report.

3. Filtration Process

We have 2 filter cartridges and a UV light post-filter, which comprise 7 filtration stages:

Stages 1-3 are performed by the composite pre-filter (non-woven fabric + activated carbon layer + scale inhibitor layer).

• Stage 1: the non-woven fabric layer is mechanical filtration, which acts like a sieve to remove solid, undissolved particulates such as dirt or rust.
• Stage 2: the activated carbon layer removes things like bad tastes and odors, chlorine/chloramine, disinfection byproducts and other organics, as well as certain metals. Removing chlorine and other contaminants protects the RO membrane from damage.
• Stage 3 is a scale inhibitor layer, which prevents dissolved hard water minerals from precipitating into scale on the RO membrane, thereby extending RO membrane life and maintaining high water production.

Stages 4-6 are performed by the composite filter (RO membrane + PP cotton + activated carbon block layer).

• Stage 4: the RO membrane uses reverse osmosis to effectively remove the vast majority of contaminants and minerals.
• Stage 5: PP cotton provides another layer of mechanical filtration to remove undissolved particulates.
• Stage 6: the activated carbon block component acts as a polishing filter to remove lingering bad tastes/odors and VOCs. In addition, the block structure provides fine mechanical filtration due to its smaller pore size compared to granular carbon.

Stage 7 is the UV post-filter, which exposes the filtered water to germicidal UV radiation prior to dispensing, inactivating microorganisms. This provides chemical-free disinfection; however, in our view, it should not be relied upon to make non-potable water safe to drink, but rather to help control microbial regrowth in stored water and prevent off-tastes from stagnation.

4. Taste and Odor Tests

In our 2024 tests, the filtered water was odorless and had a perfectly clean taste. In 2025, the water was odorless as well, and the taste was much better than our tap water but not 100% perfect.

Usability: 3.92/5.00

The Waterdrop A1 achieved a usability score of 3.92/5.00, based on its performance in the following categories:

1. Initial system assembly including filter priming (0.80/0.80)
2. Everyday use (2.62/3.70)
3. Filter replacements (0.50/0.50)

1. Initial Setup: 0.80/0.80

Assembling the Waterdrop A1 is very easy. The clear, illustrated user manual is complemented by simple-to-follow on-screen prompts on the unit’s display. In addition, the display can show a QR code linking to the product manual and service page. Plus, there’s a helpful tutorial video on YouTube.

Here’s a quick breakdown of the setup procedure:

1. Place the system on a stable surface with a clearance of at least ~8 inches on both sides of the dispenser. This space is needed for proper heat dissipation.
2. Aligning the marks on the filter and dispenser, insert filter into the designated slot in the dispenser. Press the filter down and rotate clockwise to lock. Repeat for the other filter.
3. Remove water tank cover and remove the tank, using its handle. Note that the larger chamber is the feed water tank (smaller chamber is for wastewater). Fill feed water compartment with tap water up to max fill line.
4. Reinstall feed tank and replace cover, pushing down to secure it in place.
5. Plug power cord into an electrical outlet and turn machine on. Note: the cooling function will not be active for the first two hours after powering on the system but will turn on by default two hours later.
6. Place a container > 0.8 gal under the spout on the drip tray.
7. Tap the confirm key (the water dispensing key) to proceed through the user interface and begin system flushing.
8. The system will automatically start filtering and dispensing water.
9. When the feedwater indicator lights up, remove the tank, discard the wastewater, and refill the feed tank with tap water before replacing back on the unit.
10. This process will be repeated for 3-4 tanks of water (~3.2 gallons) and takes about 30 minutes.
11. When flushing is complete, the normal user interface will appear on the display. Now your system is ready to use.

2. Day-to-Day Use: 2.62/3.70

2.1 Speed & Water Capacity: 0.64/0.98

The Waterdrop A1 is generally suited for daily use. While it lacks a carafe or external pure tank for instantly accessible water, its pump-driven dispensing speed for ambient water is still acceptable.

You can fill a 40-oz bottle from a single feed tank – no need to refill the feed tank in-between. Plus, most standard 40-oz bottles should fit under the spout without tilting, as its height is 10.5” from the base. However, in our test it took several presses of the dispense button to accomplish this – in other words, the system could not dispense 40 oz of ambient water all at once.

More specifically and using a full feed tank (~1.13 gal), in our test the system could dispense 20 oz of ambient water before stopping. After waiting 10 seconds, it dispensed another 10 oz before stopping again. After a 5 second pause, it would dispense another 2 oz, and it proceeded in this manner of rapid stop and go dispensing until the feed tank was depleted.

Unlike a 40-oz bottle, you can’t fit a standard 2-quart carafe under the spout, as it’s not high enough. You could still dispense 2 quarts without refilling the feed tank, assuming you found a carafe that would fit. However, you’d have to press the dispense button multiple times to obtain this amount, same as with the 40-oz bottle.

In contrast to ambient water, using a full feed tank, the A1 dispensed 66 oz of the hottest water in one continuous pour, which should be plenty for pretty much all beverages and instant food. It also dispensed 34 oz of refreshingly cold water in one go, allowing ~20 min for cooling ahead of time. This should be sufficient for most uses.

We also investigated how much ambient filtered water could be produced from one full feed tank, regardless of how much time or how many button pushes it took to fully process and dispense this entire volume. For the Waterdrop A1, this maximum volume was 91 oz (~11.4 cups). Assuming 25.5 cups or 31.5 cups of daily water consumption for the average US and US-family households, respectively, and 11.4 cups filtered water per full feed tank, we estimate 3 daily refills – about average for the countertop ROs we tested.

The Waterdrop A1 also filters fast enough to meet the daily water needs of the average-sized US households, and it can handle thirst bursts. In our ambient water speed tests, it could dispense 1 cup in 19.5 sec or 4 cups in 1:37 min when the water was pre-processed, meaning the feed tank was filled and allowed to filter this water first. Upon refilling the tank, it took 3:26 min to dispense 4 cups of water.

Cold water dispensing speed is slightly slower but still acceptable, taking 21.5 sec to dispense 1 cup of pre-processed water – fairly standard for the cold water countertop RO systems we tested.

Hot water is slower still, requiring 49.5 sec to dispense 1 cup of pre-processed water, which is again pretty typical for the hot water countertop RO systems we tested. Hot water is particularly slow to dispense because it must be heated on-demand; flow must be slow enough to give it time to reach the desired temperature.

Fortunately, the Waterdrop A1 provides volume presets. This helps to offset the inconvenience of slower dispensing speeds, allowing you to focus on other tasks while waiting for your water to pour.

2.2 Dispensing: 0.70/0.70

Dispensing ambient or on-demand hot/cold water is simple and splash-free. The Waterdrop A1’s large, responsive touch screen also has a very intuitive user interface.

This system has four volume presets (4, 8, 16, or 20 oz) to choose from, or you can dispense a custom volume. There are also 6 temperature presets: Cold (41-50 °F), Ambient, 113, 140, 185, or 203 °F.

You can stop dispensing early if needed by pressing any button to pause the flow. The optional child safety lock keeps your family safe from accidental hot water injuries, and there’s even a small magnetic drip tray to collect any rogue droplets.

2.3 Hot Water: 0.50/0.56

More on the hot water:

As mentioned above, the Waterdrop A1 can dispense enough hot water for virtually all typical household use cases – which we define as at least 32 oz at a time. In other words, it can produce sufficient hot water for beverages like tea, coffee or hot chocolate (8-16 oz), instant noodles/soup (14-20 oz), and cooking assist/pot jump-start (16–32 oz). In fact, in our test it could dispense up to 66 oz of ~194.2-195 °F water at one time.

The actual temperature of the dispensed hot water deviated from the presets by 4-11 °F when tested with our own thermometer. Based off the unit’s presets, we measured (A1 vs. our measurement):

• 113 °F vs. 117 °F
• 140 °F vs. 151 °F
• 185 °F vs. 191.7 °F
• 203 °F vs. 194.2-195 °F

Only at the highest temperature setting did the Waterdrop struggle to reach the preset level; in fact, at the lower hot water preset temps, the A1 tended to overshoot the desired temperature.

Assuming 190–195 °F is reliable for most beverages and instant foods, with ≥200 °F being the optimal, kettle-equivalent performance, the A1 gets hot enough for most typical uses.

This system also offers optional boiling point correction (high altitude mode), which lowers the max hot water temperature for those living at higher elevations to reduce risk of scalding injuries.

2.4 Cold Water: 0.43/0.56

More on the cold water:

As discussed previously, the A1 dispensed up to 34 oz of cold water all at once, allowing ~20 minutes for pre-cooling. Assuming ≥20 oz enables bottle refills, ≥32 oz supports extended use, and ≥48 oz is needed for multiple people or to fill a carafe, this system should provide enough cold water for most situations.

Plus, the temperature of the dispensed cold water was fairly accurate when tested with our own thermometer. Based off the unit’s temperature display, we measured (A1 display vs. our measurement): 41-46 °F vs. 43.9-49.5 °F.

Waterdrop advertises a cold water temp of 41-50 °F. Our test confirms that the system achieves this range and adequately chills the entire contents of its 0.27 gal (~34.6 oz) internal cold water tank.

Assuming <41 °F is fridge-cold, 41–45 °F is nearing fridge temps, and 46–50 °F is refreshingly cold, the A1 achieved solid marks for its ability to produce refreshingly cold water.

Cooling is optional on the Waterdrop A1 and can be activated or inactivated by pressing and holding the cooling button for 5 seconds. With the cooling function turned on, the unit’s compressor will intermittently cycle on and off, making some noise. Should you find this disruptive, you can either turn off the cooling function or utilize night mode. The latter disables both cooling and filtration, making the unit silent. Not only does this eliminate noise but it also saves energy; however, it requires you to program a start/end time.

2.5 Refilling & Size: 0.21/0.49

Refilling the Waterdrop A1 is easy once you remove the feed water tank, as it fits quite snuggly into the unit. This suggests a higher quality build but also requires more effort to lift out. Plus, the system is tall, deep, and very heavy, making it more difficult to move in order to access the tank. Placing it at the end of a counter that is open on the side would likely be the simplest solution.

There is a max fill line on the feed tank and a water shortage/change indicator to remind you when it’s time to empty the wastewater and refill.

Measuring 7.8″x17.1″x18.3″ (WxHxD), the Waterdrop A1 just fits under standard height (18”) kitchen cabinets, and at a whopping 34.6 lbs, we’d classify it as very heavy. Its footprint is also above-average compared to the other tested systems, occupying ~142.74 in2 (~0.99 ft2) – definitely not space-saving. Plus, at nearly 8” wide it is not streamlined enough to fit in narrow spots.

2.6 Other: 0.14/0.42

There are a handful of other factors that impact the Waterdrop’s overall usability.

First, it lacks a carafe to store water for later – you have to dispense into a glass, bottle, or your own container.

However, it does provide TDS monitoring of the filtered water, enabling you to keep an eye on its filtration performance over time. We found the TDS readings to be quite accurate – within 10 ppb of a separate meter.

We also like the temperature light that illuminates your glass when dispensing – white for ambient water, orange for hot, and blue for cold.

Finally, the cooling function that kicks in every once in a while makes some noise – though this can be avoided by turning cooling off or entering night mode.

3. Filter Replacements: 0.50/0.50

Filter replacements are easy as the filters are readily accessible after removing the housing lid and quickly twist in/out. The display will even show a QR code enabling you to order new filters on the Waterdrop website.

The filter change indicator light on the display also alerts you when it is time to change each filter. Rated filter life for the composite pre-filter is 500 gallons or 6 months and the composite filter is 1,100 gal or 12 months.

Assuming 500 gallons of yearly water consumption for the average household, we predict the frequency of your filter changes will be dictated by filter age rather than water consumption. Therefore, expect to replace these components every 6-12 months as indicated.

Costs: 4.42/5.00

Based on value for money, the Waterdrop A1 achieved a cost score of 4.42 out of 5.00, indicating it is priced below average for what it offers compared to competing systems (a score of 4.00 represents average value). Notably, both its upfront price and annual filter replacement costs are slightly below average compared to the other ambient/hot/cold water countertop RO systems we tested.

1. Upfront Price

As of November 4, 2025, the Waterdrop A1 is priced at $649. However, Waterdrop frequently offers sales. Using our 3% off discount code (which you can combine with most other Waterdrop promotions), you can get the A1 for as little as $479 – slightly below the $587.71 average across all the tested countertop RO systems that produce ambient/hot/cold water.

2. Long-Term Expenses for Filter Replacements

Based on 500 gallons consumption and a 500-gal or 6-month rated filter life (composite pre-filter) and 1,100-gal or 12-month filter life (composite filter), we estimate $130 in annual filter replacement costs, which is slightly below the $149.47 average across all the tested countertop ROs. Plus, you can save 10% with a filter subscription.

3. Product Warranty

The system is covered by a 1-year warranty.

4. Other Cost Factors

Other features which we feel affect the Waterdrop A1’s value include:

• UV light to prevent stagnation of the filtered water.
• Accurate TDS measurements of the filtered water.
• Dispensing light reflects water temperature.
• Child safety lock to prevent hot water injuries.
• Extras like optional boiling point correction (high altitude mode), manual flush, night mode, and vacation mode.

Additional

1. Pure-to-Drain Ratio Test

We measured a pure-to-drain ratio of ~1:0.36 in 2024, which is very low wastewater for RO systems in general. However, during our test the unit stopped dispensing with 14 oz of feed water remaining in the system; it would only continue dispensing if we added more water, which violates our test protocol. Consequently, we cannot determine whether the retained 14 oz would have generated wastewater, pure water or both, rendering that year’s test data unreliable.

In 2025, our system processed the full feed tank normally, so we have greater confidence in the accuracy of this test. Here we measured a ratio of ~1:0.58, which is low wastewater for RO systems in general and slightly better than the average ~1:0.61 across the countertop RO systems we tested.

2. Construction

The system feels sturdy and well built.

3. Optional Features

• Manual flush: if the system hasn’t been used for three consecutive days, Waterdrop recommends performing a manual flush before dispensing drinking water. This process is simple and guided via prompts on the display menu.
• Vacation mode: additionally, if you plan to be away from home or not use the dispenser for 5 or more days, you can utilize off-home mode (Vacation mode). This empties all the water from the inner water tanks – both ambient and cold water – and stops normal dispenser functioning.

4. Frequent Customer Complaints

We suspect there’s been a product refresh for the A1, as there are not that many Amazon reviews yet. However, old complaints which may have been resolved with the updated version include malfunctioning units, leaking, and unresponsive displays. Other users complained of temperature issues – hot water not being hot or cold water not being cold.

We did not experience these issues firsthand.

Bottom Line: Our #1 Cold Water + Cold & Hot Water Countertop RO (4.37/5.00)

Filtration weighted at 60%, and usability and cost at 20% each, the Waterdrop A1 scored a final rating of 4.37 out of 5.00.

If you need a countertop RO that reliably produces cold (or cold + hot) water, we recommend the Waterdrop A1.

This system achieved a great 4.50/5.00 in our filtration analysis. It produced odorless, clean-tasting water in 2024 (much improved compared to our tap water in 2025) and completely removed most contaminants in our 2024 and 2025 lab tests. While it has no NSF/ANSI-certified contaminants, it is well-covered by third-party testing.

It’s also very simple to set up and maintain. Refilling is straightforward once you remove the large feed tank – not an easy task given its size and snug fit. Filter changes, however, are a breeze.

Though it lacks a carafe for instantly accessible water, dispensing speed for both ambient and cold water are acceptable. Hot water is slower by design, but the volume presets offset this inconvenience. The A1 also dispenses enough water that is sufficiently hot or cold for most use cases, from making instant food, coffee, or tea to topping up a cold water bottle. Plus, there are 6 temp presets. Dispensing is splash-free and easy thanks to the nice touch screen, but you’ll have to hit the dispense button more than once if you want >20 oz of ambient water at a time.

Finally, it is loaded with helpful features – filter/water change indicators, low wastewater, a UV light, filtered TDS readings, a child safety lock, high altitude mode, night mode (primarily reduces noise), vacation mode, manual flushing, and a dispensing light. With lower-than-average upfront and ongoing costs, the Waterdrop A1 is our top pick for a cold (or hot + cold) countertop RO.

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