Water treatment decision guides

Repair or replace. Compare the repair against the installed cost of a new unit — $1,200–$3,800 for salt-based, per HomeGuide. A control valve replacement on a five-year-old resin tank is usually worth it. The same repair on a 15-year-old unit that has been running on untested water is throwing money at a tank whose media is likely spent. Ask the technician the age of the unit and whether the resin has ever been checked, not just what's broken.

DIY or pro. Under-sink filters are genuinely homeowner-friendly, and the professional premium is small — $170–$580 for the unit and labor combined. Whole-house is a different job: you're cutting into the main, adding a bypass, running regeneration discharge to a drain, and possibly adding a circuit at $250–$900. Do that wrong and the failure mode is water damage, which your insurer may treat unkindly if the work was unpermitted and uninspected.

Budget or premium. The honest premium features are demand-initiated regeneration (NSF/ANSI 44 recognizes manual, automatic and demand-initiated types), dual-tank operation for continuous soft water at $1,700–$5,000 installed, and standard-size replaceable media. The dishonest premiums are proprietary cartridges, unverifiable "proprietary media" claims, and financing dressed as a discount.

One rule cuts through most of it: a system you cannot maintain is not a premium system. If the local dealer is the only source of consumables and service, you have bought a subscription, not an appliance. Annual maintenance already runs $100–$300+ and salt $50–$150; you do not want a lock-in on top of that.

How to choose

Use the 50% rule against a like-for-like replacement

If the repair approaches half the $1,200–$3,800 installed cost of a comparable new unit and the current one is past ten years, replace.

Retest before you replace

Water changes. Replacing a 15-year-old softener with the same specification without a fresh test repeats whatever sizing mistake was made originally.

DIY the point-of-use, hire out the point-of-entry

The cost gap on under-sink work is small; the risk gap on whole-house work is large.

Ask what happens when the unit fails

A bypass valve means a dead softener costs you soft water, not water. Confirm one is installed.

Check consumable availability before buying premium

Standard cartridges at $15–$65 from multiple suppliers beat a proprietary equivalent every time over a 15–20 year service life.