Flagship tool
Water and wastewater operator math trainer
Operators name the math as the pass-or-fail part. This trainer generates fresh, exam-style word problems across the tested plant-math domains, shows the worked solution step by step, and coaches the exact error class (a dropped decimal, a million-gallons-per-day versus gallons-per-minute slip, a forgotten 8.34) rather than only marking you wrong. Free, no signup, and your progress stays on your device.
Core exam calculations
Foundational Moderate Hard Hard Hardest Moderate
Flow conversions (MGD, GPM, cfs)
Convert between million gallons per day, gallons per minute, and cubic feet per second, the units every other plant-math answer rides on.
Detention time
How long water sits in a tank or basin: the volume divided by the flow, the control number for sedimentation and contact.
The pounds formula
Turn a dose in milligrams per liter into pounds per day of chemical: the single most tested, most failed operator calculation.
Chlorine dose, demand, and residual
The demand-plus-residual relationship, then the feed rate: dose to what the water consumes, not just to the residual you want to see.
CT disinfection
Concentration times contact time, compared to the required CT: the drinking-water compliance calculation with the baffling-factor trap.
Filtration and loading rates
Flow spread over an area or a weir: filtration rate, surface (overflow) rate, and weir overflow rate, each a flow divided by a dimension.