Reverse Osmosis Replacement Filters: Which Set Fits Your System, and When to Change Each Stage
Buy your system maker's own refill set. None of the cheaper copy refills we checked, from 27 brands, has a certification listing at NSF, WQA or IAPMO R&T. When their Amazon titles say "NSF certified," they mean the parts are safe, not that they filter. Most systems need new pre-filters every 6 to 12 months and a new RO membrane every 2 to 3 years. Find your system below.
The 6 systems, side by side
Ordered by how many refills Amazon sells a month. "From" is the cheapest refill plan in each section, at today's Amazon prices.
| System | Certified for | Refills sold a month | From (per year) |
|---|---|---|---|
| Waterdrop G3 (G3P600, G3P800) | IAPMO R&T lists the G3P600 and G3P800 for lead, fluoride, cadmium, barium, radium and TDS (NSF/ANSI 58, certificate WC-13976). | about 23,000 | $144 |
| APEC Essence ROES-50 and ROES-PH75 | WQA lists the ROES-50 and ROES-PH75 for total dissolved solids (TDS) under NSF/ANSI 58, and nothing else. | about 9,000 | $65 |
| Bluevua RO100ROPOT (countertop) | The original RO100ROPOT has no contaminant listing that we could find. | about 8,000 | $154 |
| iSpring RCC7AK and RCC7 | NSF lists the RCC7AK-BN, RCC7AK-BLK, RCC7-BN and RCC7-BLK for lead, fluoride, TDS and 6 more contaminants (NSF/ANSI 58). | about 7,000 | $57 |
| Waterdrop G2 | We found no certification listing for the G2 at NSF, WQA or IAPMO R&T. | about 5,000 | $70 |
| Express Water RO5DX | NSF lists the RO5DX for TDS only (NSF/ANSI 58), with its membrane FLTMEME50. | about 1,500 | $37 |
Amazon prices as of November 12, 2026 at 12:18 PM ET. Prices can change; the price on Amazon is the one that counts.
Waterdrop G3 (G3P600, G3P800)
Certified for: IAPMO R&T lists the G3P600 and G3P800 for lead, fluoride, cadmium, barium, radium and TDS (NSF/ANSI 58, certificate WC-13976). Its carbon block is listed for PFOA and PFOS (NSF/ANSI 53, WC-14805) and for chlorine (NSF/ANSI 42).
- WD-G3-2CFCB, once a year ($89.00) · 2x G3-N1CF + 1x G3-N3CB
- WD-G3P600-RO, every 2 years ($109.99) · 1 RO cartridge for G3P600 only, 24 months
- WD-G3-2CFCB, once a year ($89.00) · 2x G3-N1CF + 1x G3-N3CB
- WD-G3P800-RO, every 2 years ($139.99) · 1 RO cartridge for G3P800 only, 24 months
| Stage | Code | Change it |
|---|---|---|
| Front filter (CF) | WD-G3-N1CF | every 6 months or 550 gallons |
| Carbon block (CB) | WD-G3-N3CB | every 12 months |
| RO cartridge | WD-G3P600-RO or WD-G3P800-RO | every 24 months |
Buy the RO cartridge for your exact model: the G3P600 and G3P800 cartridges are not the same. We found no copy refills for the G3. Change intervals are the maker's, from its own sets and manuals.
APEC Essence ROES-50 and ROES-PH75
Certified for: WQA lists the ROES-50 and ROES-PH75 for total dissolved solids (TDS) under NSF/ANSI 58, and nothing else. The lead and arsenic claims on some APEC listings belong to APEC's Ultimate series (RO-90 and others), not the Essence systems.
- FILTER-MAX-ES50, once a year ($64.99) · stages 1-5: sediment, 2 carbon block, 50 GPD membrane, post carbon
- FILTER-SET-ES, 2 times a year ($23.28) · 1 sediment + 2 carbon block (stages 1-3), "6 Month Set"
- MEM-ES-50, every 2 years ($34.64) · 1 membrane 50 GPD
- FI-ES-TCR-QC, every 2 years ($17.42) · 1 inline post carbon
- FILTER-MAX-ESPH, once a year ($73.99) · ROES-PH75 stages 1-6 incl. 75 GPD membrane, "1 Year Set"
| Stage | Code | Change it |
|---|---|---|
| Sediment (stage 1) | FI-ES-SED10 | every 6 to 12 months |
| Carbon blocks (stages 2-3) | FI-ES-CAB10 | every 6 to 12 months |
| RO membrane (stage 4) | MEM-ES-50 (PH75: MEM-ES-75) | every 2 to 3 years |
| Post carbon (stage 5) | FI-ES-TCR-QC | every 2 to 3 years, with the membrane |
| Alkaline pH+ (PH75 only) | FI-PHPLUS-QC | every 6 months |
APEC's "FILTER-SET" (no ES) is the Ultimate-series set and does not fit an Essence system. For a ROES-50, the codes end in ES or ES50. Change intervals are the maker's, from its own sets and manuals.
Bluevua RO100ROPOT (countertop)
Certified for: The original RO100ROPOT has no contaminant listing that we could find. WQA and NSF list it and its filters only for NSF/ANSI 372, which means the parts are lead-free, not that they remove lead. The RO100ROPOT-Lite is different: WQA lists it for lead, cadmium and TDS (NSF/ANSI 58).
- RO100ROPOT 1-Year Replacement Filter Set, every 2 years ($149.96) · PP + CTO + RO + PCF (4-pack); RO lasts 2 years
- RO100ROPOT 1-Year Replacement Filter Set, every 2 years ($89.97) · PP + CTO + PCF
- ROPOT 1-Year Remineralization Filter Set, once a year ($33.99) · 2 mineral filters
| Stage | Code | Change it |
|---|---|---|
| Sediment (PP) | stage 1 | every 12 months |
| Carbon block (CTO) | stage 2 | every 12 months |
| RO membrane | stage 3 | every 24 months |
| Post carbon (PCF) | stage 4 | every 12 months |
| Mineral filter (carafe) | mineral | every 6 months |
Amazon titles call the RO100ROPOT "WQA & NSF certified"; the listing behind that is for its materials only. Change intervals are the maker's, from its own sets and manuals.
iSpring RCC7AK and RCC7
Certified for: NSF lists the RCC7AK-BN, RCC7AK-BLK, RCC7-BN and RCC7-BLK for lead, fluoride, TDS and 6 more contaminants (NSF/ANSI 58). The plain RCC7AK and RCC7 rows are listed for TDS only. Check the full model number on your system.s label.
- F19K75, every 2 years ($139.00) · 4 sediment, 4 GAC, 4 CTO, 1 MC7-type 75 GPD membrane, 2 post-carbon, 4 alkaline
- F9K, once a year ($69.24) · 2 sediment, 2 GAC, 2 CTO, 1 post-carbon, 2 alkaline; no membrane
- MC7, every 2 years ($35.19) · 1 membrane 75 GPD
- F15-75, every 2 years ($114.20) · 4 sediment, 4 GAC, 4 CTO, 1 membrane 75 GPD, 2 post-carbon
| Stage | Code | Change it |
|---|---|---|
| Sediment (stage 1) | FP15 | every 6 months |
| Carbon (stage 2) | FG15 | every 6 months |
| Carbon block (stage 3) | FC15 | every 6 months |
| RO membrane (stage 4) | MC7 | every 2 to 3 years |
| Post carbon (stage 5) | FT15 | every 12 months |
| Alkaline (stage 6, RCC7AK only) | FA15 | every 6 months |
The RCC7AK has a 6th stage (alkaline) the RCC7 does not, so the sets differ. The UV models need the F10KU set. Change intervals are the maker's, from its own sets and manuals.
Waterdrop G2
Certified for: We found no certification listing for the G2 at NSF, WQA or IAPMO R&T. Waterdrop's G3 is listed; the G2 is not.
- WD-G2-2CFRO, every 2 years ($139.99) · 2x G2CF + 1x G2MRO
| Stage | Code | Change it |
|---|---|---|
| Front filter (CF) | WD-G2CF | every 12 months or 1,100 gallons |
| Carbon + RO cartridge (MRO) | WD-G2MRO | every 24 months |
The G2P600 takes its own RO cartridge (WD-G2P6MRO). Change intervals are the maker's, from its own sets and manuals.
Express Water RO5DX
Certified for: NSF lists the RO5DX for TDS only (NSF/ANSI 58), with its membrane FLTMEME50.
- FLTSET085Q, once a year ($65.99) · 1-year: 8 filters incl. 1x 50 GPD membrane
- FLTSETC6G6S6I3M502, every 3 years ($110.99) · same 23-filter 3-year set
| Stage | Code | Change it |
|---|---|---|
| Sediment, carbon, carbon block (stages 1-3) | in the sets | every 6 months |
| RO membrane (stage 4) | FLTMEME50 | about every 12 months |
| Post carbon (stage 5) | inline | every 12 months |
Express Water says to change the membrane about once a year, but its 3-year set holds 2 membranes. If you go by the 3-year set, add a membrane in year 2 or 3. Change intervals are the maker's, from its own sets and manuals.
Why we only link the maker's own sets
An RO system's certification covers the system with the filters its listing names. A copy cartridge is not covered unless the certifier lists it too, and none of the copies we checked is listed. Some copies say "NSF certified" in their Amazon titles (Mysora, Vegebe, SimPure, KleenWater, among others). When we looked, those claims meant lead-free materials (NSF/ANSI 372) or "tested to" a standard, not a listing to reduce anything.
Not sure what is in your water? Look up your water system. Choosing a new system? See the best reverse osmosis systems.
Questions people ask
How often should I change reverse osmosis filters?
Most makers say pre-filters (sediment and carbon) every 6 to 12 months and the RO membrane every 2 to 3 years. Tankless systems like the Waterdrop G3 use cartridges instead: front filter every 6 months, carbon block every 12, RO cartridge every 24. Follow your own maker: the schedules differ.
Are cheaper copy RO filters certified?
None we checked. We searched 27 copy brands at NSF, and 20 of them also at WQA and IAPMO R&T. None had a certification listing. When their Amazon titles say "NSF certified," they mean lead-free materials or "tested to," not a filtering claim.
Does my RO system remove lead?
It depends on the exact model. NSF lists iSpring's RCC7AK-BN and RCC7-BN for lead; WQA lists APEC's ROES-50 for TDS only; IAPMO lists Waterdrop's G3P600 and G3P800 for lead and fluoride; we found no listing for the Waterdrop G2. Each section below says what your system is certified for.
What happens if I do not change the RO membrane?
It slowly lets more through, and the water tastes worse. A TDS meter shows when it is wearing out: compare the tap reading with the RO reading.
Is it cheaper to buy a multi-year set?
Not always. For the APEC ROES-50, the full 5-stage set once a year costs less per year than buying the pre-filter set twice a year plus a membrane. Each section prices every plan from today's Amazon prices.
Sources
- NSF listings (iSpring Water Systems, Express Water): listings.nsf.org, read October 23, 2026.
- WQA Gold Seal listings (APEC, Bluevua): find.wqa.org, read October 23, 2026.
- IAPMO R&T certificates WC-13976, WC-14301 and WC-14805 (Waterdrop G3): pld.iapmo.org, read October 23, 2026.
- Change intervals: each maker's set contents on Amazon, product manuals and support pages, read October 23, 2026. iSpring's and APEC's own sites did not load for us; their intervals come from their set contents and manuals.
- Amazon listings and prices: read through Amazon's product API; we show a price only if we read it in the last 24 hours. Prices exclude tax and shipping.
- We did not test any filter.