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Own a water softener without guessing

Measure first, size second, adjust third. Every figure on this site comes with its unit, its source and its limits.

Start with the complete water softener guide

Four steps, in this order

  1. Measure

    Water Hardness Guide: GPG, PPM and What to Measure

    Translate hardness measurements into owner decisions while requiring a local report or test.

  2. Size

    Water Softener Sizing Calculator

    Calculate compensated load, usable capacity, salt-dose tradeoff and regeneration interval with visible assumptions.

  3. Set

    How to Set Water Softener Hardness

    Translate a verified test result into a controller input with iron and model caveats.

  4. Verify

    Printable Water Softener Maintenance Log

    Record test results, salt additions, regenerations, settings and service without collecting personal data.

Six-stage water softener decision map covering measurement, treatment fit, sizing and verification, model-specific configuration, maintenance records, and safe troubleshooting.
An evidence-first water softener plan carries one verified hardness result through sizing, model verification, configuration, maintenance, and symptom-based troubleshooting.

Calculators

Every input stays in your browser. Nothing is stored or sent.

Four water-hardness bands: soft through 60 milligrams per liter, moderately hard above 60 through 120, hard above 120 through 180, and very hard above 180, with approximate grains-per-gallon equivalents.
USGS water-hardness classes in mg/L as CaCO3, with gpg equivalents calculated using 1 gpg = 17.12 mg/L.

Printable sheets

Print at 100% on US Letter. No email, no sign-up.

Step-by-step, with the safety limits

Where to look

How this site works

We begin with primary sources whenever possible, including government guidance, official standards information, certification databases, performance data sheets, and exact manufacturer manuals. Calculations include visible formulas and test cases. Model-specific instructions stay attached to the cited model.

Unless a page explicitly documents otherwise, Resin Ledger has not purchased, installed, laboratory-tested, certified, or personally used the products discussed. The site does not determine whether water is potable, replace an exact manual or local requirements, or provide electrical, plumbing, medical, legal, or professional water-treatment services.

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