Best Water Softeners · head-to-head

EcoPure EP42 42,000 Grain Water Softener vs A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T)

A sourced, side-by-side comparison. A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T) is cheaper at $549. Every spec and price links to its source.

Full spec sheet

marks the stronger figure where "more" — or "less", for price and weight — is unambiguously better.

Spec EcoPure EP42 42,000 Grain Water Softener A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T)
US price $549
BrandEcoPureA.O. Smith
Released
Grain capacity 42 40
System type ion-exchange ion-exchange
Flow rate gpm
Salt efficiency lbs per kgrains
Iron removal ppm 11 10
Nsf certifications NSF Certified
Smart app control No No
Tank warranty years 10 10
Msrp usd 549

Sources — EcoPure EP42 42,000 Grain Water Softener: ecopure.com (verified 2026-06-26). A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T): aosmithatlowes.com (verified 2026-06-26).

What's the difference between the EcoPure EP42 42,000 Grain Water Softener and A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T)?

Where the two actually differ on the specs we track (2 of 9). Matching specs are omitted.

  • Grain capacity: EcoPure EP42 42,000 Grain Water Softener 42 vs A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T) 40
  • Iron removal ppm: EcoPure EP42 42,000 Grain Water Softener 11 vs A.O. Smith 40,000 Grain Water Softener (AO-WH-SOFT-400T) 10

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