Brondell Circle RC100 vs Express Water RO5DX: Which to Buy

The Express Water RO5DX is the better under-sink reverse osmosis system overall, rated 3.6 to 2.9. The Express Water RO5DX leads on filter cost and price. The Express Water RO5DX costs $180 less ($179.99 vs $359.99).

Higher rated

Express Water RO5DX

#6 in With tank3.6Full review

For a budget buyer who wants a certified system with cheap filters. Anyone paying for water or on a septic system should pick a lower waste design.

Amazon $179.99

$179.99

Brondell Circle RC100

#11 in With tank2.9Full review

For a household that wants a certified, compact tank system with a filter change reminder. Families who draw a lot of water at once will outrun its small tank.

Brondell $359.99

$359.99

Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.

Which should you buy?

Choose the Express Water RO5DX for filter cost ($81 a year in replacement filters vs $205 a year in replacement filters) and price ($179.99 vs $359.99).

Scores side by side

Each factor is scored 0-100 against the same fixed reference points for every with tank under-sink reverse osmosis system; a clear win is highlighted. How we rank explains each one.

Factor weight	Express Water RO5DX	Brondell Circle RC100
Overall rating	3.6/5	2.9/5
Certification 25%	100 certified to NSF/ANSI 58	100 certified to NSF/ANSI 58
Filter cost 20%	70 $81 a year in replacement filters	12 $205 a year in replacement filters
Water wasted 15%	50 drain ratio not published (neutral score used)	50 drain ratio not published (neutral score used)
Output 10%	0 50 gallons a day	0 40 gallons a day
Price 15%	85 $179.99	27 $359.99
Warranty 15%	0 1-year warranty	0 1-year warranty

Independent measurements

Express Water RO5DX

Tested by	TDS reduction	Output	Pure to drain	Conditions
Water Filter Guru	-	51.8 gpd	-	At 48 psi and 58.6 F.
Water Filter Guru	-	-	0.2 :1	64 oz purified to 336 oz drained (1:5.25); a 12 oz test gave 1:5.9.