Water softener (salt) · checked 16 Oct 2026
Rheem PREFERRED Platinum 42,000 Grain WiFi Water Softener
Model RHW42
Lead:not claimedPFAS:not claimed
Each claim, checked
What the brand says, what a certification listing shows for this model, and where each fact comes from. We read listings; we do not test products.
- Certified (listing checked)The certifier’s public listing shows this claim for this model.
- Brand says certifiedThe brand says certified; IAPMO’s listing does not show it. NSF can be checked by hand.
- Brand claim onlyThe brand claims it without citing a certification.
| Contaminant | Brand claim | Standard | Certifier | Confirmed? | Source, date checked |
|---|---|---|---|---|---|
| Hardness | “System tested and certified by NSF International against NSF/ANSI Standard 44 for hardness reduction, efficiency and the reduction of barium and radium 226/228” brand source | NSF/ANSI 44 | NSF (named by brand) | Brand says certified — not found in IAPMO’s listing; check NSF | IAPMO searched · check NSF’s listingchecked 16 Oct 2026 |
| Barium | Same statement as for Hardness. brand source | NSF/ANSI 44 | NSF (named by brand) | Brand says certified — not found in IAPMO’s listing; check NSF | IAPMO searched · check NSF’s listingchecked 16 Oct 2026 |
| Radium | Same statement as for Hardness. brand source | NSF/ANSI 44 | NSF (named by brand) | Brand says certified — not found in IAPMO’s listing; check NSF | IAPMO searched · check NSF’s listingchecked 16 Oct 2026 |
| Iron | “Removes clear water (Ferrous) iron that causes reddish-brown stains to form on toilets, showers and sinks” brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Particulates | “The built-in sediment filter keeps sediment out of your plumbing with no filter replacements needed.” brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Scale | “Saves up to 24% on water heater electricity costs by removing scale build-up and improving efficiency*” brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
Filter changes, by the brand’s numbers
A salt softener has no filter cartridge to change; you add salt as it runs low. Rheem doesn’t state a resin life on the brand pages we read (checked 16 Oct 2026).
Certification listings found
No IAPMO R&T listing matched this model when we searched on 16 Oct 2026.
Check it yourself
NSF’s and WQA’s terms don’t allow automated lookups, so these links open their public listings for this model:
- NSF listing search: RHW42
- NSF listing search: Rheem
- WQA listing search: RHW42
- WQA listing search: Rheem
- IAPMO R&T listing directory
What the brand says about certification
- “System tested and certified by NSF International against NSF/ANSI Standard 44 for hardness reduction, efficiency and the reduction of barium and radium 226/228, and certified to NSF/ANSI/CAN Standard 372.” source checked 16 Oct 2026
- “System tested and certified by the Water Quality Association against CSA B483.1.” source checked 16 Oct 2026
- “This system conforms to NSF/ANSI Standard 44 for the specific performance claims as verified and substantiated by test data.” source checked 16 Oct 2026
Performance data sheet (names NSF International; Water Quality Association)