Rheem Preferred Plus RHS42

What Rheem publishes, and what it does not

This record is mostly complete. What Rheem omits will not stop you sizing the unit or working out roughly what it costs to run, though you will have to ask if you want the full picture before buying.

Of the specifications a buyer actually needs to size and compare this unit, Rheem publishes 7 of 8. No third-party certification is cited on the source page.

Not published for this unit:

• water per regeneration, which matters on a septic field, where discharge volume is a design limit.

We leave those blank rather than reaching for a plausible figure. If you need one of them to decide, Rheem support is the place to get it, and it is worth asking before you buy rather than after.

How it sits in the Rheem range

The Preferred Plus RHS42 is the largest Rheem unit we track at 42,000 grains. Alongside it sits the Preferred RHS32: the Preferred RHS32 drops 10,000 grains for $100 less.

At its maximum 16.3 lb dose the Preferred Plus RHS42 works out to roughly 2,577 grains per pound of salt. That figure is the fair way to line it up against other units, because every manufacturer in this category advertises the maximum and nobody runs it there day to day.

Who this suits, and who should skip it

A good fit for:

• Mid-sized households, which is where most buyers land. 42,000 grains covers a typical family without the price of the largest units.
• Well water. A published rating of 11 ppm of iron is among the higher figures we have recorded, and iron rating is the specification that decides whether resin lasts ten years or three.
• Anyone replacing an older timer softener. A metered head regenerates on water actually used rather than on a schedule, which is where most of the salt saving in a modern unit comes from.
• Budget-led buys. At $589 this sits at the affordable end of the category, and the gap to the direct-to-consumer brands is large enough to fund years of salt.

The closest alternative on price

If you are cross-shopping, the nearest unit we track on price is the GE GXSH40V. They are priced within $20 of each other. and carries 2,000 grains less capacity. Iron rating differs too, 11 ppm here against 8 ppm there, which settles it on well water.

Mistakes to avoid at this size

• Buying the number on the box. The 42,000-grain rating is what this unit reaches at its maximum 16.3 lb salt dose. Day to day it runs a much smaller dose and delivers proportionally less per cycle, which is the honest basis for comparing it against anything else.
• Assuming the iron rating covers untreated well water. 11 ppm is a genuinely high rating, but it is a ceiling rather than a target. Sustained iron near that limit still shortens resin life, and above roughly 3 ppm a dedicated iron filter ahead of the softener is usually the better build.
• Sizing from the house instead of the water. Capacity needed is household size multiplied by hardness, so two identical houses on different water need different softeners. Test the water first, then size to the result.
• Treating the unit price as the installed cost. Installation is frequently comparable to the hardware. At $589 this unit can land at roughly double once a drain line, bypass and labor are counted, which reorders the budget rankings considerably.