Skip to content
Pickoryx

PetSafe Oasys 2-Gallon vs Drinkwell Multi-Tier: Which Fits Your Home?

Choose by the reservoir size and drinking layout you want. The Drinkwell Multi-Tier is listed at 100 oz with upper and lower bowls; the selected 2-gallon Oasys configuration is listed at 256 oz with an open bowl and adjustable stream. Neither capacity predicts refill intervals, and neither layout proves that a pet will prefer it.

Published by Pickoryx · Published 2026-10-18

Source checked 2026-10-18 02:00 UTC

Products compared

Pickoryx may earn a commission from qualifying purchases through the paid Amazon links on this page, at no added cost to you.

The buying question

Is the Oasys 2-gallon version’s larger stated capacity and open bowl a better fit than the Drinkwell Multi-Tier’s 100-ounce reservoir and upper/lower bowls?

The Oasys lists 256 oz of capacity and an open bowl with adjustable flow; the Multi-Tier lists 100 oz and provides upper and lower bowls plus its stream. Reservoir volume does not predict how often a particular household must refill either fountain.

Quick verdict

When to skip: You need a cordless fountain; both models are described as plug-in fountains.
When the recommendation changes
  • Your available placement area, household refill routine, or preferred drinking surface points to a different configuration.

The differences that matter

Household Capacity And Refill Planning

PetSafe Drinkwell Multi-Tier Pet Fountain (PWW00-13708, 100 oz)

100 oz stated capacity.[2]

PetSafe Oasys Pet Fountain (ZWW00-16558, 2 gallon / 256 oz)

The selected 2-gallon option is 256 oz.[1]

What this changes: A reader who prioritizes a larger stated reservoir can distinguish these configurations by listed capacity, but capacity alone cannot determine refill frequency for a specific home.[2, 1, 4]

The better fit depends on your priorities

Drinking Surface And Access Layout

PetSafe Drinkwell Multi-Tier Pet Fountain (PWW00-13708, 100 oz)

Upper bowl and lower bowl, with a free-falling stream.[2]

PetSafe Oasys Pet Fountain (ZWW00-16558, 2 gallon / 256 oz)

Open bowl and one free-falling stream; flow is adjustable.[1]

What this changes: Choose based on whether you want distinct upper/lower bowls or an open bowl with adjustable stream control; these documented layouts do not prove a pet preference or outcome.[2, 1]

The better fit depends on your priorities

Best for your routine

A household specifically seeking two bowl levels in one fountain

Best fit: PetSafe Drinkwell Multi-Tier Pet Fountain (PWW00-13708, 100 oz)

Based on listed features, not comparative testing.

The Multi-Tier documentation describes an upper and lower bowl as separate drinking places. Choose it for that documented layout, not for a promised change in pet comfort or health.

View PetSafe Drinkwell Multi-Tier Pet Fountain (PWW00-13708, 100 oz) on AmazonPaid link

A household prioritizing the larger listed reservoir among these two models

Best fit: PetSafe Oasys Pet Fountain (ZWW00-16558, 2 gallon / 256 oz)

Based on listed features, not comparative testing.

The selected Oasys 2-gallon configuration is listed at 256 oz versus 100 oz for the Multi-Tier. This is a stored-volume comparison only; actual refill timing depends on use and conditions.

View PetSafe Oasys Pet Fountain (ZWW00-16558, 2 gallon / 256 oz) on AmazonPaid link

Value and trade-offs

One or both observed offers have eligibility conditions, so no unrestricted price difference is shown.

No stable price premium is evaluated here. Compare the current offers and included package contents before choosing.

No price-history window was reviewed, so this comparison cannot support a buy-now or wait recommendation.

Limitations

  • The 256 oz figure is tied to the selected 2-gallon Oasys option on the manufacturer product page; do not apply it to the separate 64 oz or 128 oz options on that page.
  • Capacity is stored volume, not a refill-day estimate. Check the water level and refresh water regularly according to the product instructions and your household routine.
  • Both manufacturers describe top-rack dishwasher cleaning for fountain parts and separate hand-washing for the pump; no cleaning-frequency, hygiene, or maintenance-effort winner is established.
  • No controlled flow, noise, stability, spill, or pet-preference comparison was conducted.

Questions shoppers ask

Does 256 oz mean the Oasys can go a set number of days without a refill?

No. It is the stated capacity of the selected 2-gallon option. Water use varies, and the manufacturer advises checking the level and refreshing water regularly; do not convert reservoir volume into a guaranteed number of days.

Are the two fountains different in cleaning method?

The manufacturer pages describe top-rack dishwasher cleaning for fountain components and hand-washing the pump separately for both models. This does not establish which is easier or needs cleaning less often.

What is the main layout difference?

The Multi-Tier has an upper and a lower bowl as well as a free-falling stream. The selected Oasys is described with an open bowl and adjustable free-falling stream. Which surface a pet chooses is not established here.

Methodology and sources

Compared the selected 2-gallon Oasys option with the PWW00-13708 Multi-Tier using manufacturer capacity, bowl-layout and cleaning information. Reservoir capacities are reported as stated; no refill interval is calculated, and no performance or pet-preference winner is inferred.

AI assistance organized manufacturer-published specifications and instructions into a conditional feature-fit comparison. Pickoryx did not conduct hands-on testing.

View 4 sources
  1. 1.Oasys Pet FountainPetSafe · Official specifications · Source checked 2026-10-18 02:00 UTC
    Evidence used on this page
    • 2 Gallon (256 oz) option and specifications; Design/Water Flow; cleaning and included product guidance.: The exact part path is ZWW00-16558. The page presents 64 oz, 128 oz and 256 oz options; selecting 2 Gallon shows 256 oz and dimensions separately, while the shared page describes an open bowl, one free-falling stream with adjustable flow, and top-rack cleaning with the pump hand-washed separately. Only the selected 256 oz value is used for capacity; no dimension is compared.
  2. 2.Multi-Tier Pet FountainPetSafe Support · Official support · Source checked 2026-10-18 02:00 UTC
    Evidence used on this page
    • Features and Model Numbers.: The PetSafe Support page identifies the Drinkwell Multi-Tier model PWW00-13708 and also lists DMLR-PLAS as an associated model number. It lists 100 oz capacity, describes upper and lower bowls and a free-falling stream, and describes top-rack cleaning with the pump hand-washed separately.
  3. 3.Drinkwell Multi-Tier Pet Fountain Quick Start GuidePetSafe · Official specifications · Source checked 2026-10-18 01:59 UTC
    Evidence used on this page
    • Cover identifies PWW00-13708; printed p. 6 / PDF p. 6 for pump disassembly and printed p. 7 / PDF p. 7 for Pet Fountain Cleaning.: The manual cover names PWW00-13708. It describes taking the fountain apart and washing other parts with warm water and soap or using the dishwasher top rack; the adaptor and pump must not be put in the dishwasher. Used only to explain the documented cleaning routine, not capacity or pet outcomes.
  4. 4.How To Choose the Best Pet Water Fountain for Your Cat or DogPetSafe · Official specifications · Source checked 2026-10-18 02:00 UTC
    Evidence used on this page
    • “Capacity for your household” section.: The guide frames reservoir size as a household-size and refill-routine choice, describes capacity as stored volume rather than permission to leave a fountain unattended, and advises checking level and refreshing water regularly. Used only for bounded decision context; no hydration, health, sales-volume, or product-performance claim is taken from it.

Continue comparing