Under-sink filter · checked 16 Oct 2026
iSpring CU-A4 0.01μm Ultra-Filtration Under Sink Water Filter…
Model CU-A4 · replacement parts FP15Q, FKG15Q, FT15Q
Lead:Brand claim onlyPFAS:Brand claim only
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 |
|---|---|---|---|---|---|
| Lead | “removes up to 99% of PFAS, chlorine and chlorine treatment by-products, lead, arsenic, and much more, while retaining minerals.” brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| PFOS | “Will this under sink water filter remove pfos and pfas? | Yes, CU-A4 has a Ultra Filtration unit that can filter both.” brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| PFAS (no compounds named) | Same statement as for Lead. brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Chlorine | Same statement as for Lead. brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Other | Same statement as for Lead. brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Arsenic | Same statement as for Lead. brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Chloramine | “provides much better control of particularly problematic contaminants including chloramine, hydrogen sulfide, heavy metals, and other compounds” brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
| Hydrogen sulfide | Same statement as for Chloramine. brand source | – | – | Brand claim — no certification cited | brand pagechecked 16 Oct 2026 |
Filter changes, by the brand’s numbers
How often iSpring says to replace each part. Real filter life depends on how much water you use and what is in it.
| Part | Brand says replace every | Changes a year | Source, date checked |
|---|---|---|---|
| CU-A4 replacement cartridge set (FP15Q, FKG15Q, FT15Q)The brand gives more than one figure for this part. | 6–12 months“Filter life: 6 -12 months, depending on your source water and usage.”6–9 months or 1,100 gallons“The cartridge set has a capacity of 1100 gallons. ... The filter lifespan is 6 to 9 months depending on water quality and usage.” | 1–2 or 1.3–2 | brand sourcechecked 16 Oct 2026brand sourcechecked 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: CU-A4
- NSF listing search: iSpring
- WQA listing search: CU-A4
- WQA listing search: iSpring
- IAPMO R&T listing directory
What the brand says about certification
- “All filters, tubing and other water-contacting parts are manufactured to comply strictly with NSF/ANSI standards for safety and water quality.” source checked 16 Oct 2026