Oneisall 3.5L Cordless Stainless Steel Pet Water Fountain

Oneisall 3.5L Cordless Stainless Steel Pet Water Fountain

By Oneisall · Pet Fountains · Home & Workspace

  • 3.5 L capacity, 304 stainless steel and ABS, 7.87 x 7.87 x 6 in (20 x 20 x 15.3 cm)
  • 5000mAh rechargeable battery, up to 60 days cordless, charges over USB-C
  • 5-layer filtration, 3 carbon filters included, replace every 2 to 3 weeks

Lowest price seen
$39.99
from $39.99 at PetSmart · Checked Oct 4, 2026

Prices are snapshots. Check the current price with the store.

Problems, parts and running costs

Summary

A 3.5 L cordless stainless-steel circulating fountain for cats and small dogs, with a 5000mAh battery, three flow modes and a replaceable pump. Check the mode before you buy: constant flow works only while it is plugged in, so the 60-day battery figure depends on sensor or intermittent use.

Strengths

  • Cordless placement avoids chewed cords, and the fountain can travel with a pet.
  • Owners and a hands-on review call it quiet.
  • The top-fill tank is easy to assemble, fill and clean.
  • Replacement parts are sold separately, including the pump and the battery module.
  • Three modes, including a motion sensor owners say pets take to quickly.
  • The 2-year warranty and 30-day return are generous for the price.

Weaknesses

  • The 60-day battery claim is mode-dependent; constant flow only works on mains power.
  • Multiple dated owner reviews report pumps failing after a few months.
  • The pump needs a weekly clean, and hard water is an owner-reported issue.
  • Replacement filters can be hard to find on the maker’s site, and short shipments are reported.
  • No instrumented test of this exact model exists.
  • The control module and pump must not be immersed, and the wetted path includes some plastic.

Verified specifications

ModelPW04; 304 stainless steel plus ABS.
Capacity3.5 L (118 oz).
Battery5000mAh rechargeable over USB-C; DC 5 V / 1 A input.
Battery claimup to 60 days cordless.
Modesconstant (plug-in only), sensor and intermittent.
Sensor modetriggers when a pet moves within 39 in (1 m) at a 120° angle and runs water for 30 seconds.
Intermittent mode30 seconds of flow every 30 minutes.
Noiseunder 30 dB manufacturer rating.
Filtration5-layer; three carbon filters included, changed every 2-3 weeks.
Indicatorsfront water-level window, low-water light, filter reminder and battery lights.
Size and weight7.87 x 7.87 x 6 in (20 x 20 x 15.3 cm); 2 lb.
In the boxfountain, 5 V/1 A adapter, Type-C cord, three replacement filters, cleaning brush and manual.
Warranty2 years, with a 30-day money-back return.
Full research notes and sources

The modes, and what the battery claim really means

The interesting mode is the sensor. It triggers within 39 inches at a 120-degree angle and runs the water for 30 seconds, which is what makes the 60-day battery claim plausible rather than decorative. Intermittent mode runs 30 seconds every 30 minutes. Constant flow only works while the cable is connected, and the manual is explicit about that, so listing copy advertising “3 water modes” does not tell you the limitation. There is no independent runtime test, so treat 60 days as an unrepeated manufacturer claim, reached only in sensor or intermittent mode with low traffic.

Pump care and replacement parts

Repairability is better than the price suggests. Oneisall sells a PW04 replacement pump for $14.99, a battery module and control panel for $29.99, and PW04 filters from $10.99. The manual asks for a once-a-week pump clean with the supplied small brush, which is the single most useful line in the document. That matters because the dated owner complaints are almost all pump-related: one owner reports the pump stopping after a few months, and another reports buying two units where one arrived with a dead pump and two missing filters. Those same reviews describe support sending replacement pumps and, in one case, a replacement unit within two days. Treat a $15 pump as a nuisance rather than a write-off.

Evidence and how to read it

There is no instrumented test of this fountain from any major review outlet, which is typical for the category. The one substantial hands-on review is a Catster piece by a veterinarian who scored it 4.9 and found it quiet, simple to take apart and well liked by her five cats, but the page states Oneisall compensated her for the time and editorial work, so it is sponsored rather than independent. Her two criticisms are cosmetic: the brushed steel shows fingerprints, and the top module is off-white rather than white. Oneisall’s own blog then misattributes that review to a different veterinarian and uses it to sell a different product, which is a reason to discount brand-authored review claims here. Chewy’s listing and dated owner reviews supply the rest, clustered on quietness, easy cleaning and cordless placement.

Is it worth it?

Oneisall direct lists the PW04 with three filters at $39.99 against a $59.99 regular price, with Chewy at $36.99, Target at $39.99, PetSmart at $39.99 and Best Buy at $41.99 (2026-10-03). Two-year coverage on a roughly $40 device with a $15 replaceable pump is the argument for it. The arguments against are the weekly pump clean, the recurring filter cost at a two-to-three-week interval, and the absence of any independent performance measurement. Above $60 the comparison should widen to larger cordless fountains or deeper service networks.

Which model this is

This page covers the Oneisall PW04, the cordless 3.5 L stainless-steel fountain, sold in stainless, white and black colorways under SKUs PW04SAU, PW04WAU and PW04BAU; the US ASIN is B0DNJT76WJ. Do not confuse it with the PW03, which is corded, or with the PW13, PW14, PW17, PW01 and PW02, which differ in capacity or filtration. Match parts to model PW04 rather than to a marketplace ASIN, because the manual’s part ASINs and Oneisall’s own accessory SKUs are different systems.

Sources

Manufacturer:

Independent reviews:

Owner reports:

Retail listings:

Buying guides for this category

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