# Gauge: Water Operator Prep — One time. No subscription.

> One time. No subscription. (iPhone/iPad app by OMAR DANIEL GRAZIANO.)

- Source: https://appshunter.io/ios/app/gauge-water-operator-prep/id6803531173 (this page in markdown: same URL + `.md`)
- Developer: [OMAR DANIEL GRAZIANO](https://appshunter.io/developer/1896485759)
- Category: Education, Reference
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 5 MB
- Languages: American English
- Released: 2026-08-28
- Data updated: 2026-09-02
- User reviews in markdown: https://appshunter.io/ios/app/gauge-water-operator-prep/id6803531173/reviews.md

## What is Gauge?

Wastewater treatment operator certification prep, built around the part that actually fails people: the math.

THE CALCULATORS ARE FREE. FOREVER.

Fifty operator formulas across flow and volume, detention and loading, process control,
solids, chemical feed, pumping and power, and the laboratory. Detention time, the pounds
formula, MCRT, F/M, SVI, surface and weir overflow rate, chlorine dose, chemical feed with
purity correction, pump horsepower, wire-to-water efficiency, BOD. Each one shows the
relationship, what it means on shift, and the mistake operators most often make with it.
No account, no advertising, no network required. They stay free whether you buy anything
or not.

THE FORMULA SHEET IS SUPPLIED AT YOUR EXAM

So what is really being tested is whether you can pick the right relationship and keep
your units straight under time pressure. This app drills exactly that, with two-stage
questions: choose the formula first, then compute the value. Nothing else on the store
practises the skill the exam actually measures.

WORKED SOLUTIONS, NOT BARE ANSWERS

Every calculation shows its steps with the units carried through. Get one wrong by a
factor of 8.34 and the app tells you that you dropped pounds per gallon rather than just
marking it incorrect — because a unit slip is the most common way a prepared candidate
loses a timed exam.

BUILT TO THE PUBLISHED BLUEPRINT

Five exam areas at their published weighting, and timed practice forms drawn to the same
area weighting and calculation load as a real sitting, including the unscored pre-test
items. Your math score is reported separately from your overall score, because some
states score the calculations independently and you can clear the percentage and still
fail on them.

ACCURACY IS THE PRODUCT

Every formula in the app is covered by an automated test suite, and every worked solution
is recomputed programmatically rather than checked by eye. Explanations cite the governing
regulation where one applies, so you can verify at the source instead of trusting us.
Found something wrong? Tell us and it gets fixed in days, not years.

WORKS WITH NO SIGNAL

Everything is on the device. Plants are concrete and steel, and you will be studying in a
break room mid-shift.

FREE, AND WHAT THE UNLOCK ADDS

Free: every calculator, the formula reference, and 88 practice questions drawn from all
five exam areas. The one-time unlock opens the complete question
bank, all worked solutions, every timed form, the formula-selection drills, spaced
repetition and weak-area analytics. One payment, no subscription, no account.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Full Unlock | $14.99 | one-time |



## Version history (last 2 releases)

### 1.0.1 — 2026-09-01

Fixes a bug that could leave the unlock button disabled when the App Store price failed to load. The button now retries on its own and reports a clear error if the store cannot be reached.

### 1.0 — 2026-08-29

No release notes.

## More apps by OMAR DANIEL GRAZIANO

- [Cycle Cipher](https://appshunter.io/ios/app/cycle-cipher/id6767546105)
- [CivBites](https://appshunter.io/ios/app/civbites/id6767999584)
- [Decanon](https://appshunter.io/ios/app/decanon/id6768711973)
- [Tanksmith](https://appshunter.io/ios/app/tanksmith/id6769517856)
- [Roomprint](https://appshunter.io/ios/app/roomprint/id6769752243)
- [Liminal: Learn Philosophy](https://appshunter.io/ios/app/liminal-learn-philosophy/id6770075835)

All apps by OMAR DANIEL GRAZIANO: https://appshunter.io/developer/1896485759

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-02.*