The only meaningful difference is flow rate
| Spec | 400GPD (B0F3BTVGNF) | 600GPD (B0F3B3M1XG) |
|---|---|---|
| Flow rate | 1 L/min | 1.5 L/min |
| Daily capacity | 400 GPD | 600 GPD |
| Filtration stages | 4-stage RO | 4-stage RO (identical) |
| Membrane | 0.0001 micron TFC | 0.0001 micron TFC (identical) |
| What it reduces | PFAS, heavy metals, chlorine, VOCs | PFAS, heavy metals, chlorine, VOCs (identical) |
| Tank design | Tankless | Tankless |
| Filter life | 12 months | 12 months |
| Best for | Single faucet, smaller households | Busier kitchens, fridge/ice maker use |
Brio SIMPL 400GPD — Best Value
The 400GPD is Brio's entry model — a 4-stage tankless under-sink RO with 0.0001 micron membrane filtration, 1 L/min flow rate, and a 12-month filter cycle. The SIMPL name is accurate: color-coded tubing and a complete installation kit are included, the install is designed for DIY completion in 1–2 hours, and maintenance is a single annual filter swap.
The tankless design keeps the under-sink footprint small — there is no pressure tank taking up cabinet space. Flow at 1 L/min is comfortable for a single dedicated drinking faucet but will feel slow if you regularly fill large pots or pitchers in quick succession. For a 1–2 person household using filtered water primarily for drinking and coffee, the 400GPD hits the value target without overpaying for capacity you won't use.
Note on fridge hookups: If you want to feed a fridge ice maker or water dispenser, the 400GPD at 1 L/min is on the low end. An inline tank or booster pump is recommended for that use case — or step up to the 600GPD.
Check Price on Amazon →| Pros | Cons |
|---|---|
| ✅ Compact tankless footprint — no pressure tank needed | ❌ 1 L/min flow feels slow for large fills or high demand |
| ✅ Color-coded install kit included — DIY-friendly | ❌ Not ideal for fridge hookup without inline tank/pump |
| ✅ PFAS, heavy metals, chlorine, VOC reduction | ❌ Plastic housing — not as premium-feel as metal alternatives |
| ✅ 12-month filter cycle — annual maintenance only |
| Situation | How it helps |
|---|---|
| Small kitchens or apartments | Full RO filtration without a bulky tank — keeps cabinet usable |
| RVs and campers | Compact, tankless setup with included adapters — check pump strength for mobile pressures |
| 1–2 person household, single faucet | 1 L/min is adequate for a drinking faucet; cost advantage over the 600GPD |
Brio SIMPL 600GPD — Best Performance
The 600GPD is the same system as the 400GPD in every respect except flow rate — 1.5 L/min versus 1 L/min, and 600 GPD daily capacity versus 400. That 50% increase in flow rate is the specific reason to pay more. Filling a pitcher, kettle, or pot at the dedicated faucet takes noticeably less time. For kitchens where the RO faucet sees regular heavy use, the flow difference is felt daily.
Reviewers who chose the 600GPD over the 400GPD specifically cite the flow improvement as the deciding factor. The filtration is identical — same 4 stages, same 0.0001 micron membrane, same PFAS/heavy metal/chlorine target list, same 12-month filter cycle. If filtration performance is the only consideration, either model is equivalent. Flow rate and daily capacity is where they diverge.
Still worth noting for fridge hookups: Even at 1.5 L/min, a tankless-only setup may feel limited for a fridge ice maker or water dispenser under heavy demand. An inline tank is still worth considering for that application, though the 600GPD handles it better than the 400GPD would.
Check Price on Amazon →| Pros | Cons |
|---|---|
| ✅ 1.5 L/min flow — noticeably faster than 400GPD | ❌ Higher price than 400GPD for the same filtration result |
| ✅ Better suited for busy kitchens and high-frequency use | ❌ Inline tank still recommended for fridge/ice maker hookup |
| ✅ Same compact tankless footprint as 400GPD | ❌ Plastic housing — same finish as 400GPD |
| ✅ Identical 4-stage filtration — PFAS, metals, chlorine, VOCs |
| Situation | How it helps |
|---|---|
| Busy kitchens, 3+ person households | Higher flow handles multiple people drawing filtered water without long waits |
| Frequent large fills | 1.5 L/min makes filling pitchers, large pots, and kettles more practical |
| Fridge / ice maker hookup | Better suited than 400GPD for this use — still consider an inline tank for sustained demand |
Fridge and ice maker hookup — what you need to know
A tankless RO system produces water on demand — it filters water as you draw it, rather than storing pre-filtered water in a pressure tank. For a dedicated drinking faucet this works fine. For a fridge ice maker or water dispenser, which draw water in bursts and need reliable pressure on demand, a tankless-only system can struggle to keep up.
The practical fix is a small inline pressure tank (typically 2–4 litres) installed between the RO output and the fridge line. This stores a buffer of pre-filtered water so bursts from the ice maker or dispenser draw from the tank rather than waiting for the RO to filter in real time. The 600GPD handles fridge hookup better than the 400GPD without additional hardware, but either model benefits from an inline tank for that application.
Filter replacement schedule
| Filter stage | Replacement interval | Signs it's due early |
|---|---|---|
| Pre-filter (sediment + carbon) | 6–12 months | Reduced flow; taste or odor returning |
| RO membrane | 12 months (Brio rating) / 2–3 years (typical TFC) | Output TDS rejection drops below 85%; rising output TDS |
| Post-carbon polishing | 12 months | Flat or off taste from output faucet |
Brio rates all filters at 12 months. Under normal municipal water conditions, the RO membrane typically lasts 2–3 years in practice — the 12-month rating is conservative and accounts for variable water quality. Monitor with a TDS meter: when output TDS rejection drops below 85%, replace the membrane regardless of time elapsed.
Always flush the system for 10–15 minutes after any filter replacement before collecting drinking water. TDS monitoring guide →
Common questions
What is the difference between the 400GPD and 600GPD?
Flow rate and daily capacity. The 600GPD delivers 1.5 L/min versus 1 L/min and 600 GPD capacity versus 400 GPD. Filtration stages, membrane specification, filter life cycle, contaminants addressed, and installation hardware are identical. Pay more for the 600GPD if you have a busy kitchen, want to feed a fridge or ice maker, or regularly fill large vessels. The 400GPD is sufficient for a 1–2 person household with a single drinking faucet as the primary use.
Do I need a tank or pump?
Not for a single drinking faucet. For a fridge ice maker or water dispenser, a small inline pressure tank (2–4 L) is recommended for either model — it buffers water so the ice maker draws from stored filtered water rather than waiting for the RO to filter on demand. The 600GPD handles fridge use better than the 400GPD without additional hardware, but both benefit from an inline tank for that application.
How often do filters need replacing?
Brio rates all stages at 12 months. Pre-filters (sediment and carbon) are typically replaced on schedule or earlier if flow drops or taste returns. The RO membrane under normal municipal water often lasts 2–3 years in practice — track with a TDS meter and replace when rejection drops below 85%. Flush for 10–15 minutes after any filter change before use.
Is installation difficult?
No — the Brio SIMPL ships with a complete kit including color-coded tubing and adapters. Anyone comfortable shutting off a supply line and routing tubing under the sink can complete it in 1–2 hours. You'll need an existing or drilled faucet hole. If under-sink plumbing is non-standard or complex, a plumber is a fast solution.