Under sink water filter dimensions: will it fit your cabinet?
Height, footprint, tank size and power needs of 11 under sink water filters and reverse osmosis systems from iSpring, APEC, Aquasana, A. O. Smith, Waterdrop, Express Water and Frizzlife, with a fit check for your cabinet.
Dimensions read by hand from each maker's product page on 18 October 2026, plus Aquasana's install guide for its clearance note. We have not installed or measured these systems ourselves. How we research | How links work
The short answer
Measure the clear space under your sink: floor to the lowest pipe or disposal, and the width and depth that are free of pipes. Then compare it with the system's labeled height and footprint. Of the 11 current systems here, the 8 whose makers label their height stand 8.75 to 18 inches tall, 4 to 5.5 inches on their narrow side and 8 to 17.75 inches on their long side. Systems with a tank need extra room for it, and 3 makers do not say which figure is the height.
Will it fit under your sink?
Enter your three measurements
The check uses the 8 systems whose makers label their height.
Every system, shortest first
Footprint is the two sides other than the height, as the maker gives them; it can face either way along the wall. Systems whose makers do not label the height come last, with their own wording.
| System | Type | Height (in) | Footprint (in) | Tank | Needs power | Clearance note | Maker's wording | Source |
|---|---|---|---|---|---|---|---|---|
| A. O. Smith AO-US-200 (2-stage) | Filter, no tank | 8.75 | 4 x 8 | "Height 8.75 in., Width 4 in., Depth 8 in." | A. O. Smith | |||
| Aquasana Claryum 3-Stage (AQ-6300) | Filter, no tank | 9 | 4.25 x 12 | Mount at least 12" above the cabinet floor for filter changes (install guide) (guide) | "4.25" x 12" x 9" (L x W x H)" | Aquasana | ||
| A. O. Smith Clean Reverse Osmosis (AO-US-RO-MB-4000) | Reverse osmosis with tank | 12.5 | 4 x 12 | Water storage tank included (no tank size given) | "Height 12.5 in., Width 4 in., Depth 12 in." | A. O. Smith | ||
| Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2) | Reverse osmosis with tank | 12.93 | 15 x 4.5 | Tank 13.74" x 9.06" (H x D), 3.2 gallon total volume | "Manifold 15" x 4.5" x 12.93" (L x W x H)" | Aquasana | ||
| iSpring RO500-BN | Tankless reverse osmosis | 16.25 | 17.5 x 5.12 | Yes (booster pump; FAQ says the power cable is about 3 feet) | "17.5"L x 5.12"W x 16.25"H" | iSpring | ||
| APEC ROTL-600 | Tankless reverse osmosis | 16.5 | 17.75 x 5.5 | Yes ("Electrical outlet is required") | "17.75"w x 5.50"d x 16.5"h" | APEC | ||
| APEC ROES-50 | Reverse osmosis with tank | 17 | 15.5 x 5.25 | 4 gallon tank, 11" x 11" x 15" | "15.5" L x 5.25" W x 17" H" | APEC | ||
| iSpring RCC7 | Reverse osmosis with tank | 18 | 15.5 x 5.1 | 3.2 gallon storage tank (no tank size given) | No ("doesn't require any power source") | "15.5"L x 5.1"W x 18.0"H" | iSpring | |
| Waterdrop G3P600 | Tankless reverse osmosis | Yes ("Electricity Required: Yes") | About 1 inch gap between the system and the cabinet (FAQ) | "Product Dimensions (In) 18.11*5.67*17.73 (order not labeled)". The FAQ on the same page gives 17.72 for the last figure. | Waterdrop | |||
| Express Water Alkaline RO (ROALK10MBN) | Reverse osmosis with tank | Water Tank Size: 3.2 Gallon Water Capacity (the box list says 4 gallon water storage tank) | "Dimensions: 17 x 15 x 5 (order and unit not labeled)" | Express Water | ||||
| Frizzlife PD600-TAM3 | Tankless reverse osmosis | "PD600: 5.3"L x 14.7"W x 15.5" (third figure not labeled); TAM3 filter: 5" x 5" x 13.5"" | Frizzlife |
Express Water's page also disagrees with itself on the tank: its specifications say 3.2 gallons and its box list says a 4 gallon tank. Waterdrop's specification line gives 17.73 for the last figure and its FAQ gives 17.72.
Next step
Empty the cabinet, take the three measurements to the nearest pipe, and keep about an inch spare on each side. If a maker does not label its height, ask before ordering for a tight space.
Common questions
Which measurement matters most?
Height from the cabinet floor to the lowest pipe or the bottom of the garbage disposal. The systems here stand 8.75 to 18 inches tall, so a cabinet with a low disposal can rule out the taller reverse osmosis units even when there is plenty of floor space.
Do I need room for a tank?
Only for reverse osmosis systems with a tank (5 of the 11 here). APEC gives its 4 gallon tank as 11" x 11" x 15" and Aquasana gives its SmartFlow tank as 13.74" tall and 9.06" across. iSpring and A. O. Smith include a tank but do not give its size on the pages we read.
Do tankless systems need an outlet under the sink?
The ones whose pages say so do: iSpring RO500-BN, APEC ROTL-600, Waterdrop G3P600. Check before you buy if there is no outlet in the cabinet. iSpring says its RCC7 with a tank does not need power.
Why are some heights missing?
Because the maker does not say which figure is the height. Waterdrop G3P600, Express Water Alkaline RO (ROALK10MBN), Frizzlife PD600-TAM3 list three numbers without saying which is which. We left those cells empty rather than guess; ask the maker before you rely on them in a tight cabinet.
Method
- Systems. Current under sink filters and reverse osmosis systems whose maker page gives dimensions, read one page at a time on 18 October 2026.
- Dimensions. Copied as the maker words them. Height and footprint are filled in only where the maker labels which figure is the height; where it does not, the cells are empty and the maker's wording is shown.
- Fit check. A system passes if its height is at or below your clear height and its two other sides fit your free width and depth, turned either way. Tanks are listed but not checked, because most makers do not give the tank's size.
- Not covered. Room for hoses, fittings, the drain saddle and the faucet hole, filter performance and certifications. We did not install or measure any system. Leave room to remove cartridges; Aquasana asks for at least 12 inches above the cabinet floor for its Claryum.
Sources
Changes
- : Published. 11 systems from 7 makers, each read on the maker's page on 18 October 2026.