## Operator Math Part 1: Practical Guidelines

Mathematical calculations can be a challenge for even for the most veteran of water and wastewater operators. The formulas for volume, chemical dosage, filtration, pipe velocity, and other daily problems vary of course, but there are a few underlying guidelines that can help you make sure your answer is correct regardless of the calculation you’re working on.

This is the first in a three-part series dedicated to operator math. The tips below are adapted from information provided by the South Dakota Department of Environmental and Natural Resources.

- Learn what a formula means, not just when it is used. This will help you remember when to use πR2H to calculate the volume of a cylinder instead of 2πRH—the formula for measuring the surface area of a cylinder’s sides.
- Use unit labels throughout your calculation to help you easily see whether you need to multiply or divide.
- Always convert percentages to decimals.
- Convert “inches” to “feet” unless you’re trying to solve a pressure problem. Using “inches” in any other problem will almost always leave you with the wrong answer.
- Make sure the units you end with match the problem you are trying to solve. If a volume calculation results in a “square feet” or “square yards” answer, something went wrong along the way.
- Trust your suspicions. If the answer doesn’t seem right, check that you used the right formula and units before running the problem again.

For those looking for more detailed and specific instruction, our documents database is a great place to start. Here are some of the resources you’ll find if you search “math.”

This 24-page handbook is a basic math study tool. It provides formulas for basic geometry, velocity & flow rates, and pressure, force & head, and contains several typical water problems that show users how to apply the formulas in real-world scenarios.

Formula and Conversion Sheet for Drinking Water Treatment and Distribution

This 1 page document provides conversions and formulas for water treatment & distribution operators in studying for a certification exam.

Chlorine Contact Time Calculations

This 7-page document provides guidelines on how to solve math problems that deal with calculating chlorine contact time. It includes important equations and practice problems with solutions.

This 7-page document provides a list of valuable formulas and conversion factors important for wastewater operators.

This 37-page study guide contains 82 intermediate water math questions. Solutions to the problems are provided at the end of the document.

This 29-page study guide contains 35 advanced wastewater math questions. Solutions to the problems are provided at the end of the document.