Planning figure: ten to fifteen years for a metered system on municipal water with its salt routine and an occasional $20–60 part; eight to ten is the honest expectation for big-box units, and iron-heavy wells shorten everything until pretreatment exists. Here is what drives the spread and what to watch as the years pass.
What sets the lifespan
| Factor | Effect |
|---|---|
| Chlorine exposure | Degrades resin; city water without pre-carbon trims resin life |
| Iron and manganese | Fouls resin and valve; wells without pretreatment shorten life dramatically |
| Valve platform | Generic-parts platforms stay repairable; proprietary heads age into replacement decisions |
| Sizing correctness | Chronic undersizing means constant regen and accelerated wear |
| Salt routine | Bridging left unfixed starves cycles and stresses the valve |
The timeline of a typical ownership
- Years 1–3: salt refills and nothing else, if sizing was right.
- Years 4–8: first injector cleaning, possibly a brine bridge, a motor module on some heads. $0–60 events.
- Years 8–12: harder valve parts decisions; this is where generic-parts platforms justify themselves against proprietary ones (economics here).
- Years 10–15: resin exhaustion on city water arrives; a $200–400 rebed can add five years to a sound tank and valve.
Replace or rebed?
A ten-year-old unit with a sound tank and a tired resin bed is a rebed candidate. The same age with a failed proprietary valve head is usually a replacement: parts exceed half the cost of new hardware from the value tiers. Check your sizing one last time before the new purchase; households change over a decade, and the calculator takes two minutes to confirm the old unit’s capacity still matches the house. Age is not the only explanation for a unit that has stopped working: check whether it is actually using salt and whether regeneration frequency matches the sizing math before you write it off.