PUR Faucet Filter Replacement: RF9999 vs RF3375, Which Mounts Take Each Cartridge, and the Cross-Fits That Claim to Fit
PUR's sheet gives RF9999 and RF3375 one rating: 100 gallons, 0.52 gpm, NSF/ANSI 42, 53 and 401, and one fit list of 24 mounts from FM2500V to PFM400H.
- Verified
- Updated
- 8 min read
- 4 sources
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OwnerSpec compares published manufacturer specifications, certification listings and sourced technical documents. Unless a page explicitly states otherwise, OwnerSpec has not laboratory-tested or used the products it compares. Editorial policy
Short answer
The PUR faucet filter replacement is either the RF9999 (sold as PUR PLUS, with the Mineral Core) or the RF3375 (plain PUR), and PUR’s performance data sheet dated 28 October 2025 prints one identical fit list for both: the same 24 faucet mount models, from the older FM2000B, FM2500V and FM3700B to the current PFM400H, PFM410F and PFM800HX. The same sheet gives both cartridges one rating: 100 gallons capacity, 0.52 gallons per minute rated service flow, and testing to NSF/ANSI 42, 53 and 401, certified by IAPMO R&T per the sheet. PUR’s faucet support page sets the interval at every 3 months or 100 gallons, whichever comes first. The one spec that must match is the mount model: if yours is on PUR’s 24-model list, either cartridge clips in; if it is not, PUR publishes no fit for it. On Amazon only the RF9999 is sold under PUR’s own name; the RF3375 appears only in third-party compatibility claims.
Fact sheet
- Answer
- PUR’s performance data sheet lists the RF9999 and the RF3375 with one fit list of 24 faucet mount models, from the FM2500V to the PFM400H, and one rating: 100 gallons, 0.52 gpm, tested to NSF/ANSI 42, 53 and 401. PUR’s faucet support page sets the interval at every 3 months or 100 gallons.
- Applies to
- RF9999
- RF3375
- Compatibility basis
- PUR Performance Data Sheet for faucet mount filters (28 October 2025 filename), served under both the RF9999 and the RF3375 URLs with identical content
- Assumptions
- Certifications are listed per PUR’s sheet; no NSF, WQA or IAPMO R&T listing database entry was reached on 2026-09-13
- The Waterdrop and AQUA CREST cross-fit claims come from their Amazon listing titles only; neither maker’s own site listed a PUR-compatible cartridge on 2026-09-13
- Method
- Fit list, capacity, flow, standards, reduction percentages and operating limits copied from PUR’s performance data sheet and faucet support FAQ; nothing was tested and no cartridge was opened.
- Primary source
- PUR, Performance Data Sheet, RF9999 faucet mount filter (28 Oct 2025, PDF) (manufacturer or vendor document)
- Facts verified
- Last updated
- Cite as
- OwnerSpec, "PUR Faucet Filter Replacement: RF9999 vs RF3375, Which Mounts Take Each Cartridge, and the Cross-Fits That Claim to Fit", https://ownerspec.com/water/parts/pur-faucet-filter-compatibility-rf9999-rf3375/, facts verified 13 September 2026.
Every figure above also appears, with its source, in the page below. All sources · How OwnerSpec verifies numbers
The picks
Own a mount on PUR's list; 2 cartridges, 6 months
PUR PLUS RF9999 faucet filter, 2-pack
100 gal and 0.52 gpm per PUR's sheet; NSF/ANSI 42, 53 and 401 listed per the maker; 3 months or 100 gal each
Same mount; 6 cartridges, 18 months at 3 months each
PUR PLUS RF9999 faucet filter, 6-pack
Same cartridge and the same PUR figures as the 2-pack; 2, 4 and 6-pack options on one listing
Chlorine taste only; listing claims, not PUR's numbers
Waterdrop PUR-compatible faucet filter, 6-pack
Listing claims NSF 42, 1,800 gal and 18 months; no NSF/ANSI 53 or 401 claim; not on Waterdrop's own site
Same caveat as Waterdrop; 5 cartridges
AQUA CREST RF9999-compatible faucet filter, 5-pack
Listing claims NSF 42 and 1,800 gal; no NSF/ANSI 53 or 401 claim; AquaCrest's PUR collection page is empty
What fits
Own a mount on PUR's list; 2 cartridges, 6 months
PUR PLUS RF9999 faucet filter, 2-pack
100 gal and 0.52 gpm per PUR's sheet; NSF/ANSI 42, 53 and 401 listed per the maker; 3 months or 100 gal each
Same mount; 6 cartridges, 18 months at 3 months each
PUR PLUS RF9999 faucet filter, 6-pack
Same cartridge and the same PUR figures as the 2-pack; 2, 4 and 6-pack options on one listing
Chlorine taste only; listing claims, not PUR's numbers
Waterdrop PUR-compatible faucet filter, 6-pack
Listing claims NSF 42, 1,800 gal and 18 months; no NSF/ANSI 53 or 401 claim; not on Waterdrop's own site
Same caveat as Waterdrop; 5 cartridges
AQUA CREST RF9999-compatible faucet filter, 5-pack
Listing claims NSF 42 and 1,800 gal; no NSF/ANSI 53 or 401 claim; AquaCrest's PUR collection page is empty
The thing people pay extra for is the word PLUS on the box, not a spec: PUR prints the same 100 gallons, the same 0.52 gpm and the same NSF/ANSI lines for both cartridges.
Which PUR faucet mounts take the RF9999 and which take the RF3375?
Both cartridges fit every mount PUR names. PUR’s performance data sheet (28 October 2025 filename) lists one set of 24 faucet unit models, and the sheet PUR serves at the RF3375 URL carries the same 24; no PUR mount takes one cartridge and not the other.
| Mount series on PUR’s list | Models named on the sheet | Takes |
|---|---|---|
| FM series (8 models) | FM2000B, FM2100B, FM2500V, FM2700G, FM2800N, FM3333B, FM3700B, FM4000B | RF9999 or RF3375 |
| PFM series (16 models) | PFM100B, PFM150W, PFM200B, PFM222B, PFM244W, PFM270G, PFM300V, PFM310M, PFM350V, PFM360F, PFM400H, PFM400HC, PFM410F, PFM420W, PFM450S, PFM800HX | RF9999 or RF3375 |
The genuine cartridge on Amazon is the RF9999 2-pack or the RF9999 6-pack . No PUR-branded RF3375 listing exists there; the RF3375 name appears only in third-party cross-fit titles.
What does PUR publish for each cartridge?
The figures below are PUR’s published figures from its performance data sheet; OwnerSpec tested nothing. No NSF, WQA or IAPMO R&T listing database entry was reached on 2026-09-13, so every certification here is listed per the maker’s sheet, not confirmed in a registry.
| Spec | RF9999 (PUR PLUS) | RF3375 (PUR) | Where PUR states it |
|---|---|---|---|
| Filter capacity | 100 gallons | 100 gallons | Performance data sheet |
| Rated service flow | 0.52 gallons per minute | 0.52 gallons per minute | Performance data sheet |
| Standards | NSF/ANSI 42, 53 and 401, certified by IAPMO R&T per the sheet | Same | Performance data sheet |
| Lead at pH 6.5 | 99.70% from a 0.15 mg/L challenge | Same | Performance data sheet |
| Total PFAS | 99.92% from a 0.00216 mg/L challenge | Same | Performance data sheet |
| Chlorine taste and odor | 98.71% from a 2.0 mg/L challenge | Same | Performance data sheet |
| Water temperature | 34°F to 82°F (1°C to 28°C) | Same | Performance data sheet |
| Working pressure | 20 to 100 psig | Same | Performance data sheet |
| Mineral Core | Yes | No | PUR’s product naming |
PUR does not publish a pore-size micron rating for either cartridge. The current sheet states Class I particulate reduction, 0.5 to under 1 micron, at 99.65 percent; the prior revision gave 99.1 percent for the same claim. Either way it is a test result and not a micron rating.
The prior revision of the sheet (4 September 2025 filename) named NSF International and WQA as the certifiers; the current revision names IAPMO R&T. Neither prints a revision date inside the text; the dates are the file names’ only.
Does the RF9999 fit older mounts like the FM-2500V?
Yes. The FM2500V is on PUR’s 24-model list alongside the other FM-series mounts, and PUR publishes no separate, narrower list for the RF9999. What PUR does not publish is a standalone spec sheet for the FM-2500V or the PFM400H mount itself.
Neither mount is sold as its own Amazon listing. A search for the FM-2500V surfaced only PUR’s current vertical system, whose own copy names it the FM-3700B, a different mount. If the mount rather than the cartridge is what needs replacing, the faucet mount water filter review compares the current systems on published spec.
What else fits the same mounts?
Two cross-fit cartridges were confirmed as live Amazon listings on 2026-09-13. Their claims are theirs alone.
| Alternative | Pack | What the listing title claims | What the maker’s own site showed on 2026-09-13 |
|---|---|---|---|
| Waterdrop PUR-compatible filter | 6-pack (1 to 8-count options on one listing) | Compatible with all PUR faucet filters, NSF 42 certified, 18 months, 1,800 gallons | No PUR-compatible cartridge in Waterdrop’s navigation or replacement-filter collection |
| AQUA CREST RF-9999-compatible filter | 5-pack | Fits all PUR Plus mounts, NSF 42 certified, 1,800 gallons | AquaCrest’s PUR faucet filter collection page returned no products |
Both listings claim NSF 42 only. NSF/ANSI 42 covers aesthetic effects such as chlorine taste and odor; PUR’s lead and PFAS figures sit under Standard 53, which neither cross-fit title claims. The 1,800 gallon claim is 18 times PUR’s 100 gallons with no maker document behind it.
How often do they need replacing?
PUR’s faucet systems support page says to replace PUR faucet filters every 3 months or 100 gallons, whichever comes first.
PUR publishes no condition that shortens the interval beyond those two limits. The sheet’s operating window, 20 to 100 psig and 34°F to 82°F, is the only other constraint it prints. PUR’s support page gives no counterfeit-detection procedure at all: no hologram, lot code or authorized-seller list appears.
Which cartridge to buy
The RF9999 costs the PLUS premium for a Mineral Core that PUR’s sheet gives no performance line of its own, and the RF3375 with the same 100 gallon, 0.52 gpm rating is not sold under PUR’s name on Amazon, so the genuine choice there is the RF9999 2-pack for one mount or the RF9999 6-pack for 18 months of changes. Buy the Waterdrop or AQUA CREST cross-fit only if chlorine taste is the whole job: their titles claim NSF 42 and nothing under 53. Skip all four if your mount is not one of the 24 on PUR’s list: PUR publishes no fit for it.
Frequently asked questions
Does the PUR RF9999 fit the same faucet mounts as the RF3375?
Yes. PUR's performance data sheet dated 28 October 2025 prints one list of 24 compatible faucet unit models, and PUR serves the same sheet under both the RF9999 and the RF3375 file names. Every FM and PFM mount on that list, from the FM2000B to the PFM800HX, takes either cartridge, and PUR publishes no narrower list for either one.
How often should a PUR faucet filter be replaced?
PUR's faucet systems support page says to replace PUR faucet filters every 3 months or 100 gallons, whichever comes first. The 100 gallon figure is the filter capacity printed on the performance data sheet. PUR publishes no separate figure for the Mineral Core in the RF9999, so both cartridges run on the same 3-month, 100-gallon schedule.
Is the RF9999 a better filter than the RF3375?
Not on any figure PUR publishes. The performance data sheet gives both the same 100 gallon capacity, 0.52 gallons per minute rated flow and the same NSF/ANSI 42, 53 and 401 reduction table, including 99.70 percent lead at pH 6.5 and 99.92 percent Total PFAS. The difference PUR names is the Mineral Core in the PUR PLUS RF9999, which the sheet does not rate.
Does the RF9999 fit older FM-series mounts like the FM-2500V?
Yes. The FM2500V is named on PUR's compatible faucet unit list for the RF9999 and RF3375, alongside the FM2000B, FM2100B, FM2700G, FM2800N, FM3333B, FM3700B and FM4000B. PUR publishes no standalone spec sheet for the FM-2500V mount itself, so the fit rests on that list, and a mount PUR does not name should be checked against its own manual.
Do the Waterdrop and AQUA CREST cross-fit filters carry the same certification as PUR's?
Their Amazon listing titles claim NSF 42 certification and 1,800 gallons; neither claims NSF/ANSI 53 for lead or 401. On 2026-09-13 Waterdrop's own site listed no PUR-compatible cartridge and AquaCrest's PUR faucet collection was empty, so no maker document supports the claims. A reader who needs PUR's lead or PFAS figures should stay with the genuine cartridge.
Sources
- PUR, Performance Data Sheet, RF9999 faucet mount filter (28 Oct 2025, PDF) (manufacturer or vendor document)
- PUR, Performance Data Sheet served at the RF3375 URL, identical content (28 Oct 2025, PDF) (manufacturer or vendor document)
- PUR, Performance Data Sheet, prior revision at the RF3375 URL, naming NSF International and WQA (4 Sep 2025, PDF) (manufacturer or vendor document)
- PUR, Faucet Systems Support and FAQs (manufacturer or vendor document)