Gauge: Water Operator Prep

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.