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How this review was put together: from AquaTru’s performance data sheet and the Under Sink owner’s manual (links in “Sources” at the end), checked against IAPMO R&T’s certification listings. We have not tested this system ourselves. How we review. Last checked October 28, 2026.
The short version
The AquaTru Under Sink is a compact under-sink reverse osmosis (RO) system with a small holding tank, three twist-in cartridges (AquaTru counts four stages, because the first cartridge combines sediment and carbon), a dedicated faucet, and an electronic module that tracks filter life and shuts off the water if its leak sensor gets wet. It runs on house pressure; the electronics run on three AA batteries.
What sets it apart is how much of its contaminant list is certified rather than just claimed. The certifier is IAPMO R&T, not NSF International. IAPMO R&T lists the Under Sink (models ATU100/ATU200) under NSF/ANSI 58 (file W-10194) for TDS, lead, fluoride, arsenic (pentavalent), nitrate/nitrite and other contaminants; under NSF/ANSI 53 (file W-10193) for VOCs and PFOA/PFOS; and under NSF/ANSI 401 (file W-10195) for listed emerging compounds, including microplastics. The trade-offs: a hard-water limit of 10 grains per gallon, slower production than bigger tank systems, and proprietary filters.
See the AquaTru Under Sink on Amazon (paid link)
Who it suits, and who should look elsewhere
A good fit if you
- Want certified lead, fluoride or PFOA/PFOS reduction at the kitchen tap, not just a marketing list.
- Are on city water with hardness at or below 10 grains per gallon (about 171 mg/L), or already have a water softener.
- Like a leak sensor that shuts off the supply, and filter-change reminders, under the sink.
- Prefer quick twist-in cartridges over unscrewing housings with a wrench.
Probably not the right pick if you
- Have hard water above 10 gpg and no softener. AquaTru says scale will build up quickly on the membrane and does not recommend it unless the water is softened first. Check your utility’s water quality report, or test it.
- Need a lot of RO water quickly (big families, filling large pots, a fridge and ice maker on the same line). The certified daily production is 54 gallons per day, and the tank is small.
- Want generic, standard-size filters you can buy from many brands. AquaTru’s cartridges are proprietary.
- Rent or can’t drill. AquaTru’s countertop purifier (a different product) needs no plumbing.
Key specifications
From AquaTru’s performance data sheet and the Under Sink owner’s manual.
| Spec | AquaTru Under Sink | What it means in practice |
|---|---|---|
| Type | Under-sink RO with holding tank, no pump | Runs on house pressure. Batteries power only the alerts and leak shut-off. |
| Cartridges | Pre-filter (sediment + carbon), RO membrane, VOC carbon filter (or VOC carbon with “pH+ Mineral Boost”) | Three twist-in cartridges, no housings to unscrew. |
| Daily production rate | 54 gallons per day | Certified test figure. Plenty for drinking and cooking for most homes, less than larger tank systems. |
| Efficiency rating | 25% | Under typical-use test conditions, about 1 gallon in 4 that enters the system ends up as drinking water; the rest goes to the drain. |
| Recovery rating | 50% | Membrane-only figure with the tank bypassed. The efficiency rating is the more realistic number. |
| Feed pressure | 40–85 psi | |
| Feed water temperature | 40–100°F, cold line only | |
| Max hardness | 10 gpg (171 mg/L) | The limit most likely to rule it out. Soften first if you are above it. |
| Max feed TDS | 1,500 mg/L | Lower than some RO units rated to 2,000. |
| Iron, manganese, sulfide | Under 0.1 mg/L | Well water with iron needs treating before RO. |
| Power | 3 AA batteries | For filter-life tracking and leak alerts. No outlet needed. |
| Warranty | 1-year limited (owner’s manual) | Filters are not covered. |
Certification: what was verified
Status: certified by IAPMO R&T (not NSF International), confirmed in IAPMO R&T’s listings on October 28, 2026. IAPMO R&T is an ANSI-accredited certifier, so its listing counts the same as an NSF International or WQA listing. AquaTru has no NSF International listing, so “NSF certified” would be wrong. The Under Sink appears in the IAPMO R&T files as models ATU100 and ATU200 (the data sheet names the ATU100 and the current manual names the ATU200).
What each IAPMO R&T file covers for the Under Sink (ATU100/ATU200):
| IAPMO R&T file | Standard | Under Sink claims on the listing |
|---|---|---|
| W-10194 | NSF/ANSI 58 (reverse osmosis) | TDS, lead, fluoride, arsenic (pentavalent), barium, chromium, copper, cysts, nitrate/nitrite, radium 226/228, selenium. The ATU200 listing adds uranium; the ATU100 listing adds perchlorate. Rated 54 gallons per day. |
| W-10193 | NSF/ANSI 53 (health effects) | VOCs, PFOA and PFOS, at a 360-gallon capacity. No lead claim under NSF/ANSI 53 for the Under Sink; its lead claim is under NSF/ANSI 58. |
| W-10195 | NSF/ANSI 401 (emerging compounds) | Listed emerging compounds, including some pharmaceuticals, BPA and microplastics. |
AquaTru’s data sheet also cites NSF/ANSI 42 (chlorine, chloramine and particulates) and NSF/ANSI 372 (lead-free materials, not a reduction claim). We have not checked those two IAPMO R&T listings model by model, so treat them as maker-stated.
What that does and doesn’t tell you:
- It does confirm the claims most people buy RO for: lead, fluoride, arsenic (V) and nitrate under NSF/ANSI 58, and PFOA/PFOS under NSF/ANSI 53. That is a broader certified list than many online RO systems, which often certify TDS only.
- The TDS figure is modest for RO. The data sheet shows 75.7% minimum and 87.1% average TDS reduction in the test. That passes the standard, but it is lower than some conventional RO systems (the Whirlpool WHER25 lists about 90% average). If you judge RO by a TDS meter, expect readings that aren’t near zero.
- Arsenic needs care. The arsenic claim is for pentavalent arsenic only. If you are on a well with arsenic, AquaTru’s own “Arsenic Facts” section explains how to check which form you have.
- PFOA/PFOS only, not every PFAS. IAPMO R&T lists the PFOA/PFOS claim under NSF/ANSI 53 (file W-10193); AquaTru’s data sheet refers to the NSF P473 test protocol. Either way it covers PFOA and PFOS specifically, not every PFAS. See is there a water filter that removes forever chemicals?
- Like every RO system, it is not meant for water that is microbiologically unsafe or of unknown quality.
What we like and what to weigh up
Strengths
- Broad certified claim list, including PFOA/PFOS (NSF/ANSI 53) and microplastics (NSF/ANSI 401), all from one certifier, IAPMO R&T.
- Leak protection. An automatic shut-off leak detector cuts the supply if it gets wet. The manual warns it only works if the filter manifold sits flat and level.
- Twist-in filters with reminders, by audible alarm, indicator lights or the AquaTru app.
- No outlet needed under the sink, because the electronics run on batteries.
- A holding-tank sanitizer fitting (AquaTru calls it TruPure) is included, and the manual has a routine for sanitizing the tank when you change the VOC filter.
Drawbacks
- The 10 gpg hardness limit. Many US homes, especially on well water, have water harder than that. Factor in a softener if you need one.
- Proprietary cartridges, so you depend on AquaTru for replacements.
- Waste water. A 25% efficiency rating means roughly three gallons to the drain for every gallon you drink, typical for a tank RO system without a pump.
- Modest TDS reduction compared with some other RO systems (see above).
- Short base warranty: one year in the manual.
Maintenance and running costs
AquaTru’s replacement schedule (whichever comes first):
| Cartridge | Replace | Note |
|---|---|---|
| Pre-filter (sediment + carbon) | Every 6 months | The data sheet says 600 gallons, the ATU200 manual says 360 gallons. Go by the alert or 6 months. |
| RO membrane | Every 24 months or 1,200 gallons | The arsenic claim depends on replacing it on time. |
| VOC filter (or VOC with pH+ Mineral Boost) | Every 12 months or 360 gallons | AquaTru suggests sanitizing the holding tank at the same time. |
| AA batteries | When the battery light blinks | The leak alerts and filter tracking stop working without them. |
What drives the cost: the twice-yearly pre-filter and yearly VOC filter are the regular spend; the membrane comes round every two years. Because the cartridges are proprietary, compare the current price of a full year of AquaTru filters against standard-size systems before you buy. Prices change often, so we don’t quote them here.
Alternatives worth comparing
- Hard water and want a big-box brand with an NSF listing? The Whirlpool WHER25 is NSF-listed under NSF/ANSI 58 for lead, fluoride, arsenic (V), cysts and more, also with a 10 gpg hardness limit.
- Want generic 10-inch filters? The APEC ROES-PH75 uses standard housings, though its WQA certification covers TDS only.
- Want a broad NSF-listed claim set and standard housings? See the iSpring RCC7AK-BLK.
- Want faster flow and less waste? A tankless unit such as the Frizzlife PD600 needs an outlet, and read our notes on its certification claims.
- Comparing them all: see our best under-sink reverse osmosis systems guide.
Common questions
Does the AquaTru Under Sink remove PFAS?
IAPMO R&T lists PFOA and PFOS reduction for the Under Sink (ATU100/ATU200) under NSF/ANSI 53 (file W-10193). RO is also one of the treatment types the EPA says can greatly reduce PFAS. That claim covers PFOA and PFOS, not every PFAS compound.
Is the AquaTru Under Sink the same as the AquaTru countertop purifier?
No. The countertop AquaTru is a plug-in unit you fill by hand. The Under Sink connects to your cold water line and drain and feeds a dedicated faucet. They use different filters.
Will it take the sodium out of softened water?
RO is the usual way to reduce sodium at the drinking tap after a softener, and with a softener upstream the 10 gpg hardness limit stops being a problem. See how to remove sodium from softened water.
Does it add minerals back?
Only if you use the “VOC Carbon with pH+ Mineral Boost” cartridge in place of the standard VOC filter. AquaTru doesn’t publish an output pH or mineral level.
Check current availability of the AquaTru Under Sink on Amazon (paid link)