Best water softener for city water: grain capacity, resin volume, salt efficiency, NSF/ANSI 44 and regeneration water use, by published spec
Whirlpool WHES40: 40,000 grains at 15.5 lb salt, 1.14 cu ft resin, 8.5 gpm, NSF/ANSI 44 certified per its manual, 3.0 gal per 1,000 grains regen.
- Verified
- Updated
- 12 min read
- 9 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
For municipal water with no iron, the Whirlpool WHES40 is the best water softener on published spec: Ecodyne’s manual rates it at 40,000 grains at 15.5 lb of salt, 1.14 cu ft of resin, 8.5 gpm service flow and 4,958 grains per pound at the 2.4 lb minimum dose, states that it is certified by NSF International against NSF/ANSI 44, and prints regeneration water use at 3.0 gallons per 1,000 grains. The runner-up is the GE GXSH40V: 40,000 grains at 15.1 lb, 9.5 gpm and the better efficiency at 5,090 grains per pound, but its sheet says the system “conforms” to NSF/ANSI 44, a maker’s statement rather than a third-party certification. Neither was on Amazon this session; the Aquasure Harmony AS-HS48D and AS-HS64D were, at 48,000 and 64,000 nominal grains with no published resin volume, flow or efficiency figure. Skip every unit here until the water report gives a hardness number in grains per gallon, and skip this page if that report shows iron.
Fact sheet
- Answer
- For city water with no iron, the Whirlpool WHES40 is the pick: Ecodyne’s manual rates 40,000 grains at 15.5 lb of salt, 1.14 cu ft of resin, 8.5 gpm, 4,958 grains per pound at the minimum dose, certification by NSF International against NSF/ANSI 44, and 3.0 gallons of regeneration water per 1,000 grains. The GE GXSH40V matches the capacity at 15.1 lb with 5,090 grains per pound but prints only a conforms statement.
- Comparison basis
- Published manufacturer specifications compared on grain capacity at each salt dose, resin volume in cubic feet, salt efficiency in grains per pound at the rated minimum dose, NSF/ANSI 44 wording, valve type, service flow in gpm and whether a regeneration water figure is printed, read from each maker’s manual, spec sheet or product page on 2026-09-13.
- Assumptions
- Municipal supply with zero iron and zero manganese on the water report; any iron sends the reader to the well-water softener page instead
- Hardness known in grains per gallon from the utility’s water quality report or a test, converted from mg/L at 17.1 mg/L per grain
- Method
- OwnerSpec compared published manufacturer specifications from the Whirlpool WHES40 manual, the GE GXSH40V specification sheet, the Rheem RHS32 manual, the Aquasure Harmony owner’s manual and the AFWFilters, Kenmore and SoftPro product pages; it did not test any softener hands-on.
- Primary source
- Whirlpool Water Solutions (Ecodyne), WHES40 and WHES44 Installation and Operation Manual, 7345469 (PDF) (manufacturer or vendor document)
- Facts verified
- Last updated
- Cite as
- OwnerSpec, "Best water softener for city water: grain capacity, resin volume, salt efficiency, NSF/ANSI 44 and regeneration water use, by published spec", https://ownerspec.com/water/reviews/best-water-softener-city-water/, facts verified 13 September 2026.
Every figure above also appears, with its source, in the page below. All sources ยท How OwnerSpec verifies numbers
The picks
Above 40 gpg or a large household, sold on Amazon
Aquasure Harmony AS-HS48D
48,000 grains nominal, Aquatrol digital metered head, 8 minute brine fill, 125 psi max inlet; resin volume, flow, salt efficiency and NSF/ANSI 44 status not published
Highest nominal capacity on the page, sold on Amazon
Aquasure Harmony AS-HS64D
64,000 grains nominal, Aquatrol digital metered head, 10 minute brine fill, 125 psi max inlet; resin volume, flow, salt efficiency and NSF/ANSI 44 status not published
If the water report shows any iron at all, this is the wrong page: the best water softener for well water page compares the same two 40,000-grain units on their published iron ceilings, and nothing below accounts for iron.
How was this shortlist built?
Every figure on this page is the manufacturer’s published specification, read on 2026-09-13 from the Whirlpool WHES40 manual (7345469), the GE GXSH40V specification sheet (49-50283), the Rheem RHS32 manual, the Aquasure Harmony owner’s manual (v3.5) and the AFWFilters, Kenmore and SoftPro product pages. Nothing was bench-tested and no unit carries a rating from this site.
The units were compared on the specs that decide whether a softener fits a city supply: grain capacity at each salt dose, resin volume in cubic feet, salt efficiency in grains per pound at the rated minimum dose, the exact NSF/ANSI 44 wording, valve type, service flow in gpm, and whether the maker prints a regeneration water figure at all.
NSF/ANSI 44 is the standard for residential cation-exchange water softeners. NSF’s and WQA’s listing databases both refused the request on every attempt this session, so every certification here is stated per the maker’s own document and was not cross-checked against the standards body.
That matters because “certified by NSF International” and “conforms to NSF/ANSI 44” are different statements, and the table records which one each maker prints.
Only the two Aquasure units were found as complete units on Amazon this session. Whirlpool, GE, Rheem and Kenmore sell through big-box stores; AFWFilters and SoftPro sell direct.
How do the units compare on paper?
| Model, maker’s published figures | Capacity at max salt dose | Resin | Efficiency at min dose | Valve | Service flow | NSF/ANSI 44 wording | Regeneration water |
|---|---|---|---|---|---|---|---|
| Whirlpool WHES40 | 40,000 gr at 15.5 lb | 1.14 cu ft | 4,958 gr per lb | Proprietary head, not named | 8.5 gpm | Certified by NSF International, per the manual; also NSF/ANSI 372 | 3.0 gal per 1,000 gr, 37.1 gal at max dose |
| GE GXSH40V | 40,000 gr at 15.1 lb | 1.11 cu ft | 5,090 gr per lb | Proprietary head, not named | 9.5 gpm | Conforms for its capacity claims, per the sheet | 2.7 gal per 1,000 gr, 37.0 gal at max dose |
| Rheem RHS32 | 33,000 gr at 14.1 lb | 0.88 cu ft | 4,940 gr per lb | Proprietary head, not named | 7.9 gpm | Certified by NSF International, per the manual; also NSF/ANSI 372 | 1.9 gal per 1,000 gr, 33.3 gal at max dose |
| AFWFilters Fleck 5600SXT 48K | 48,000 gr nominal | 1.5 cu ft, 8% crosslink | Not published | Fleck 5600SXT | Up to 12 gpm, 28 gpm peak | Not stated on the page | Not published |
| Aquasure Harmony AS-HS48D | 48,000 gr nominal | Not published | Not published | Aquatrol digital metered head | Not published | Not stated in the manual | Not published |
| Aquasure Harmony AS-HS64D | 64,000 gr nominal | Not published | Not published | Aquatrol digital metered head | Not published | Not stated in the manual | Not published |
| Kenmore Elite 520 | 31,000 gr nominal | Not published | Not published | “1 inch ultra flow valve” | Not published | “Meets NSF standards”, no number | Not published |
| SoftPro Elite Smart HE | 32,000 to 64,000 gr options | Not published | Not published | Not disclosed | Not published | Badges only, no number | Support reply says about 30 gal, not a printed spec |
The nominal grain figure is the capacity at the maximum salt dose. The three certified units publish three tiers, and the efficiency rating applies only at the lowest one.
| Salt dose tier | Whirlpool WHES40 | GE GXSH40V | Rheem RHS32 |
|---|---|---|---|
| Maximum | 40,000 gr at 15.5 lb | 40,000 gr at 15.1 lb | 33,000 gr at 14.1 lb |
| Middle | 31,600 gr at 9.0 lb | 31,500 gr at 8.7 lb | 27,600 gr at 8.3 lb |
| Minimum | 11,900 gr at 2.4 lb | 11,700 gr at 2.3 lb | 13,000 gr at 2.6 lb |
| Rated efficiency at minimum dose | 4,958 gr per lb | 5,090 gr per lb | 4,940 gr per lb |
| Efficiency floor the document states | Not less than 3,350 gr per lb | Not less than 4,000 gr per lb | Not less than 3,350 gr per lb |
| Maximum hardness rated | 125 gpg | 110 gpg | 105 gpg |
Which size does the hardness number point to?
The utility’s water quality report gives hardness in mg/L or ppm more often than in grains per gallon. The water hardness unit converter converts at 1 gpg = 17.1 mg/L, and the water softener size calculator turns that number and the household size into a grain capacity.
Hardness is not TDS: EPA lists a non-enforceable secondary standard of 500 mg/L for total dissolved solids, and a softener is sized on the hardness line, not that one.
| Hardness on the water report | Path by published spec |
|---|---|
| Under 25 gpg, household under 4 people | 32,000-grain class: Aquasure AS-HS32D or the SoftPro 32K option |
| 25 to 40 gpg, typical household | 40,000-grain class: WHES40 or GXSH40V, rated to 125 and 110 gpg supply |
| Above 40 gpg, or a large household | 48,000 to 64,000-grain class: AFWFilters 5600SXT 48K, Aquasure AS-HS48D or AS-HS64D, SoftPro 48K or 64K |
| Any iron or manganese on the report | Not this page: the well-water softener review covers iron ceilings |
Whirlpool WHES40: buy it or skip it?
Buy it if the report sits in the 25 to 40 gpg band and the household wants the unit whose certification, efficiency and regeneration water figures all sit in one manual. Ecodyne’s manual states certification by NSF International against NSF/ANSI 44, certification to NSF/ANSI 372, and WQA certification to CSA B483.1.
The limits are in the same manual: 125 gpg maximum hardness, 8.5 gpm rated service flow, 1.14 cu ft of resin, an efficiency floor of not less than 3,350 grains per pound of salt, and 3.0 gallons of regeneration water per 1,000 grains, 37.1 gallons at the maximum dose.
Skip it if the house draws more than 8.5 gpm at once, because GE rates the GXSH40V 1 gpm higher.
Skip any listing titled “WHES40E” until the rating decal shows code LL40: Ecodyne’s manual names only LL40 and LL44, and the one Amazon page carrying the E suffix read as unavailable on 2026-09-13, so there is no purchase link here. The WHES30 and WHES40 parts page covers the unit once it is installed.
Alternative: the GE GXSH40V, which trades the third-party wording for 132 more grains per pound and 1 gpm more flow.
GE GXSH40V: buy it or skip it?
Buy it if salt use and flow are the deciding specs. GE’s sheet rates 5,090 grains per pound at the 2.3 lb dose with a stated floor of not less than 4,000 grains per pound, 9.5 gpm service flow, 1.11 cu ft of resin, and 2.7 gallons of regeneration water per 1,000 grains, 37.0 gallons at the maximum dose.
Skip it if a third-party certification is required rather than a maker’s statement: the sheet’s wording is that the systems “conform to NSF/ANSI 44 for the specific capacity claims as verified and substantiated by test data”.
Skip it above 110 gpg, GE’s ceiling, where Whirlpool rates to 125 gpg. No complete unit was found on Amazon this session, only nozzle and venturi kits and valve motors.
Alternative: the Whirlpool WHES40, for the certification wording.
Aquasure Harmony AS-HS48D and AS-HS64D: buy them or skip them?
Buy one if the report is above 40 gpg or the household is large, and an Amazon-available unit with a digital metered head matters more than a full spec sheet.
Aquasure’s owner’s manual (v3.5) lists the Harmony line at 32,000, 48,000 and 64,000 nominal grains with brine fill times of 6, 8 and 10 minutes by size, an Aquatrol digital metered head, a 125 psi maximum inlet pressure, and a 2 year limited warranty extendable to 5 years with registration.
Skip both if a document stating resin volume, service flow, salt efficiency or NSF/ANSI 44 status is required before buying: the manual gives nominal capacity and brine-fill time and nothing else on that list.
That is the flaw to admit before the link: on paper these are the least documented units on the page, and the only ones with a purchase link.
Alternative: the AFWFilters Fleck 5600SXT 48K, sold direct, which prints the resin volume and flow the Aquasure manual does not.
What about the Rheem, the Fleck build, the Kenmore and the SoftPro?
| Unit | What the maker publishes | Why it is not the pick |
|---|---|---|
| Rheem RHS32 | Certified by NSF International against NSF/ANSI 44 and 372 per the manual; 33,000 gr at 14.1 lb, 0.88 cu ft, 7.9 gpm, 4,940 gr per lb, 1.9 gal per 1,000 gr, 105 gpg ceiling; 1 year warranty extendable to 5 with Rheem RHWSC cleaner | Lowest capacity, flow and hardness ceiling of the three certified units; no complete unit found on Amazon |
| AFWFilters Fleck 5600SXT 48K, SKU WS48-56SXT | 48,000 gr nominal, 1.5 cu ft of 8% crosslink resin, up to 12 gpm service and 28 gpm peak, Fleck 5600SXT valve (BR5600SMS-SXTPW), 5 year valve and 10 year tank warranty | No NSF/ANSI 44 statement, no grains-per-pound table and no regeneration figure on the page; the only named, field-serviceable valve here |
| Kenmore Elite 520 | 31,000 gr, rated to 100 gpg, 1 inch ultra flow valve, 1 year parts and labor, 3 years electronics, 10 years tanks | Softener-plus-carbon hybrid, smallest nominal capacity on the page, “meets NSF standards” with no number |
| SoftPro Elite Smart HE | 32,000, 40,000, 48,000 and 64,000 grain options, limited lifetime valve warranty, 60-day money back; NSF and WQA badges with no standard number; a support reply cites about 30 gallons per regeneration | Dealer-direct with no public resin volume, flow or valve brand, so it cannot be compared on paper |
Before you buy a softener
Do not order any unit until the hardness line on the water report is a number in grains per gallon. Convert from mg/L at 17.1 mg/L per grain on the water hardness unit converter, then run the water softener size calculator.
Under 25 gpg is a 32,000-grain question, 25 to 40 gpg is the WHES40 or GXSH40V, and above 40 gpg is where the Aquasure Harmony AS-HS48D or Aquasure Harmony AS-HS64D earns its nominal capacity.
The salt usage calculator then shows what the dose setting costs in pounds a year.
What goes wrong?
The unit is sized on the nominal figure and run at the maximum dose. Whirlpool’s 40,000 grains needs 15.5 lb of salt per regeneration; at the 2.4 lb setting the same tank delivers 11,900 grains.
A demand-metered unit set to the real hardness number regenerates on gallons used, and the pellets, crystals or potassium page covers what goes in the brine tank.
A “conforms” line is read as a certification. GE’s sheet and Kenmore’s page both state conformance or “meets NSF standards” without a third-party certification sentence; only the Whirlpool and Rheem manuals print “certified by NSF International”.
Regeneration water goes unbudgeted. Five of the eight units publish no figure at all; the three that do range from Rheem’s 1.9 to Whirlpool’s 3.0 gallons per 1,000 grains, which is the difference between 33.3 and 37.1 gallons down the drain per full cycle.
The city supply turns out to carry chlorine or chloramine at a level the resin warranty cares about. The chlorine and chloramine guide covers the carbon stage that goes ahead of the softener; none of the eight documents here prints a chlorine ceiling for its resin, so the maker’s warranty terms are the only guide.
Frequently asked questions
What does NSF/ANSI 44 certification mean on a softener, and how is a conforms claim different?
NSF/ANSI 44 is the standard for residential cation-exchange water softeners. Rheem's RHS32 manual states the unit is certified by NSF International against NSF/ANSI Standard 44 for hardness reduction, efficiency and the reduction of barium and radium 226/228, which is a third-party certification. GE's GXSH40V sheet says the system conforms to NSF/ANSI 44 for its capacity claims as verified by test data, which is the maker's own statement.
Why do two 40,000 grain softeners use different amounts of salt?
Because the efficiency rating is taken at the minimum salt dose, not the maximum. Whirlpool's WHES40 manual rates 4,958 grains per pound at its 2.4 lb setting and GE's GXSH40V sheet rates 5,090 grains per pound at 2.3 lb, each from its own NSF/ANSI 44 efficiency test. At the maximum dose both deliver 40,000 grains, from 15.5 lb and 15.1 lb of salt respectively.
How much water does a softener use to regenerate?
Only three makers on this page print the figure. Rheem's RHS32 manual states 1.9 gallons per 1,000 grains of hardness removed and 33.3 gallons at the maximum salt dose; Whirlpool's WHES40 manual states 3.0 gallons per 1,000 grains and 37.1 gallons; GE's GXSH40V sheet states 2.7 gallons per 1,000 grains and 37.0 gallons. AFWFilters, Aquasure, Kenmore and SoftPro publish no figure.
Is TDS on the water report the same as hardness?
No. EPA's secondary drinking water standards list a non-enforceable 500 mg/L guideline for total dissolved solids and name hardness among its aesthetic effects, but a softener is sized on hardness in grains per gallon, not on the TDS figure. Read the hardness line of the utility report, convert from mg/L at 17.1 mg/L per grain if needed, and size from that number.
Is the Whirlpool WHES40E a different model from the WHES40?
Not according to Ecodyne's manual, which covers the WHES40 and WHES44 line under model codes LL40 and LL44 and names no E variant. The WHES40E name appears on retailer listing titles, and the Amazon listing that carries it read as unavailable on 2026-09-13. Confirm code LL40 on the rating decal before assuming a listing is the certified unit described in the manual.
Sources
- EPA, Secondary Drinking Water Standards: Guidance for Nuisance Chemicals (government or regulatory source)
- Whirlpool Water Solutions (Ecodyne), WHES40 and WHES44 Installation and Operation Manual, 7345469 (PDF) (manufacturer or vendor document)
- GE Appliances, GXSH40V and GXSH45V Specifications and Performance Claims, 49-50283 (PDF) (retailer listing or retailer-hosted document)
- Rheem, RHS32 Preferred Water Softener Manual (manufacturer or vendor document)
- AFWFilters, Fleck 5600SXT 48,000 Grain Water Softener product page (manufacturer or vendor document)
- Aquasure, Harmony Series Water Softener Owner's Manual (v3.5) (manufacturer or vendor document)
- Aquasure, Water Softeners collection (manufacturer or vendor document)
- Kenmore Water Solutions, Elite 520 product page (manufacturer or vendor document)
- SoftPro Water Systems, Elite Smart HE product page (manufacturer or vendor document)