A.O. Smith Water Softener Specs — Grain, Iron & Warranty
A.O. Smith water softener models compared: grain capacity, iron limits, flow and warranty from official sources, linked line by line.
Quick answer
A.O. Smith's published softener lineup covers 3 models spanning 35,000 to 45,000 grains, all demand-initiated (metered) regeneration. Every figure below is captured from official A.O. Smith sources with the link shown — match any model's grain rating against your requirement from the size calculator before comparing anything else.
Manufacturer datasheet · 2026-11-06A.O. Smith softener lineup at a glance
A.O. Smith publishes some of the highest clear-water iron ratings in its class — up to 10 ppm on the models below. If you are on an iron-bearing well, that ceiling (not grain capacity alone) decides whether A.O. Smith is even a candidate: check it against your tested iron, then the tier against the size calculator.
Every figure traces to an official A.O. Smith source (linked per table); anything the sources don't state is marked "(to be verified)" rather than guessed.
A.O. Smith A.O. Smith at Lowe's Whole-Home Softener Line (AO-WH-SOFT series) (Residential)
| Model | Grain capacity | Regen | Iron limit | Flow | Warranty | Shop |
|---|---|---|---|---|---|---|
| AO-WH-SOFT-350C | 35,000 | Metered | 10 ppm | (to be verified) | 3 years mechanical & electronic parts + 10 years media tank/main control valve/brine cabinet | Amazon ↗ |
| AO-WH-SOFT-400T | 40,000 | Metered | 10 ppm | (to be verified) | 3 years mechanical & electronic parts + 10 years media tank/main control valve/brine cabinet | Amazon ↗ |
| AO-WH-SOFT-450T | 45,000 | Metered | 10 ppm | (to be verified) | 5 years mechanical & electronic parts + 10 years media tank/main control valve/brine cabinet | Amazon ↗ |
AO-WH-SOFT-350C — official spec notes: Compact(salt-sensing tech); max hardness 90 gpg; salt storage 105 lbs; H32 x W15 x D19 in / 95 lbs; 2.7" mono touchscreen.
AO-WH-SOFT-400T — official spec notes: max hardness 100 gpg; audible salt alert + power loss protection; H39.5 x W22.8 x D18.1 in / 120 lbs.
AO-WH-SOFT-450T — official spec notes: max hardness 100 gpg.
Manufacturer datasheet · 2026-11-06How to read these specs against your sizing
Three checks before buying any A.O. Smith model: first, get your required rated capacity from the size calculator (hardness + household + iron); second, verify the model's rated iron limit exceeds your tested iron — same-tier models differ here more than anywhere else; third, confirm service flow rate covers your peak simultaneous use (bathrooms × 3–4 GPM as a working figure). The warranty column rewards a slow read: tank, valve and electronics terms are listed separately by most brands and they are not equal.
Salt and maintenance context
Whatever the tier, running cost is mostly salt: expect on the order of 40–80 lb per month for an average household (the regeneration calculator computes it for your exact load), plus an occasional resin cleaner where iron is present. Every model in the current A.O. Smith lineup regenerates on demand (metered), which tracks actual water use rather than a calendar — the feature that keeps salt bills honest.
Which A.O. Smith tier fits which household
At 15 gpg (very common hard water), the A.O. Smith lineup covers: a couple (needs ≈ 21,000 grains rated) → 35,000-grain; a family of four (≈ 42,000) → 45,000-grain; a family of six (≈ 63,000) → outside this lineup. Six-person households on very hard water generally outgrow single-tank retail units — a duplex system or the next brand tier up serves better. Different hardness moves these fast: every ±5 gpg shifts a typical family one tier — see the sizing chart for the full matrix.
This page is independent — no affiliation with A.O. Smith; brand names are trademarks of their owners. Compare A.O. Smith side by side with other brands on the brand index.
FAQ
Is a A.O. Smith water softener the right size for my home?
A.O. Smith sells multiple grain tiers, so the question is which tier, not which brand. Size first — hardness × household on the [size calculator](/#calculator) — then check the grain column below: the lineup spans 35,000–45,000 grains, and step one tier up if you are between sizes or have iron.
Where do these A.O. Smith specifications come from?
Every figure is captured from A.O. Smith's own published material — official product pages, spec sheets and installation manuals — with the source link shown under each table and a capture date. Nothing on this page comes from retailer listings or third-party claims.
Why do some fields say (to be verified)?
When A.O. Smith doesn't publish a figure for a field — a flow rating, a salt dose — the cell stays marked rather than estimated. The missing number changes nothing about the specs that are published, and the [regeneration calculator](/regeneration-calculator) works from rated capacity, which every model states.
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