Express Water RO5 vs PUR PLUS FM-3700B — Which Should You Buy?
Side-by-side comparison of Express Water RO5 and PUR PLUS FM-3700B. We compare specs, performance, and value to help you decide.
Feature Comparison
| Feature | Express Water RO5 | PUR PLUS FM-3700B |
|---|---|---|
| Type | 5-stage RO | 2-stage carbon |
| Capacity | 75 GPD | 100 gallons |
| Stages | 5 (+ UV/alkaline options) | — |
| Removes | Lead, arsenic, fluoride | Lead, chlorine |
| Tank | 3.2 gallon | — |
| UV | Optional | — |
| Alkaline | Optional | — |
| Warranty | 1 year | 90 days |
| Certification | — | NSF |
| Filter Life | — | 3 months |
| Installation | — | Under sink |
| Faucet | — | Included |
Express Water RO5
Pros
- ✓5-stage RO
- ✓UV optional
- ✓Alkaline optional
- ✓Removes 99%
- ✓Fast flow
- ✓3.2-gal tank
- ✓Good for large families
Cons
- ✗Add-ons increase cost
- ✗Standard waste ratio
- ✗Bulky under sink
PUR PLUS FM-3700B
Pros
- ✓Budget-friendly
- ✓NSF certified
- ✓Reduces lead, chlorine
- ✓2-stage
- ✓Simple install
- ✓Dedicated faucet
- ✓Trusted brand
Cons
- ✗Basic filtration
- ✗Doesn't remove fluoride
- ✗Filter life 3 months
Our Verdict
Express Water RO5
The best under-sink RO with upgrade options for UV and alkaline water.
Limited Offer — Check Today's PricePUR PLUS FM-3700B
The best budget under-sink filter—basic NSF-certified filtration at the lowest price.
Limited Offer — Check Today's PriceOur Methodology
We test each under-sink filter for contaminant reduction, installation ease, and long-term cost. No manufacturer has editorial influence.
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