Gauge: Water Operator Prep
One time. No subscription.
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
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.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Adds an occasional invitation to rate the app on the App Store. It appears a few seconds after the app opens, no more than a few times a year, and never once you have left a rating. Lessons, quizzes and the field calculators are unchanged.
The developer, OMAR DANIEL GRAZIANO, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- OMAR DANIEL GRAZIANO
- Size
- 5.1 MB
- Category
- Education
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Full Unlock $14.99
- Copyright
- © 2026 Stack Trace Studios
