Express Water RO5DX
#6 in With tankFull 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
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 certification, price and filter cost. The Home Master TMAFC-ERP wins on warranty. The Express Water RO5DX costs $239.91 less ($179.99 vs $419.90).
Home Master TMAFC-ERP
#10 in With tankFull review
For someone who wants low water waste and mineralized water without needing an outlet. Buyers who want an NSF/ANSI 58 certification should look elsewhere.
Amazon $419.90$419.90
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 certification (certified to NSF/ANSI 58 vs no third-party certification), price ($179.99 vs $419.90) and filter cost ($81 a year in replacement filters vs $113 a year in replacement filters).
- Choose the Home Master TMAFC-ERP for warranty (5-year warranty vs 1-year warranty).
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 | Home Master TMAFC-ERP |
|---|---|---|
| Overall rating | 3.6/5 | 2.9/5 |
| Certification 25% | 100 certified to NSF/ANSI 58 | 0 no third-party certification |
| Filter cost 20% | 70 $81 a year in replacement filters | 49 $113 a year in replacement filters |
| Water wasted 15% | 50 drain ratio not published (neutral score used) | 82 1:1 pure to drain |
| Output 10% | 0 50 gallons a day | 0 50 gallons a day |
| Price 15% | 85 $179.99 | 15 $419.90 |
| Warranty 15% | 0 1-year warranty | 100 5-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. |
Home Master TMAFC-ERP
No independent test published yet.
Specifications
| Express Water RO5DX | Home Master TMAFC-ERP | |
|---|---|---|
| Filtration | ||
| Output | 50 gallons a day | 50 gallons a day |
| Pure to drain | - | 1:1 |
| Stages | 5 | 7 |
| Remineralization | No | Yes |
| NSF/ANSI 58 | Yes | No |
| Other certifications | NSF/ANSI 372 | - |
| Replacement filters | $81 a year | $113 a year |
| Build | ||
| Tank | 3.2 gal | 3.2 gal |
| Booster pump | No | No |
| Smart faucet | No | No |
| Warranty | 1 year | 5 years |