Water Distribution
Entry Level (DS-I)

Entry-Level Water Distribution

A complete prep course built around the standard entry-level distribution exam outline: regulations and operator certification under the Safe Drinking Water Act, distribution operation and maintenance, disinfection and chlorine residual, hydraulics and pumps, sampling and water quality, safety, and applied distribution math. Includes a diagnostic assessment, mode-switching practice engine, math drills with worked solutions, and a full timed practice exam.

10

Practice questions

50

Exam questions

90 min

Timed exam

6

Math drill types

Exam outline and weighting

Passing score for this exam is 70%. Topic weights below match how the exam distributes its questions.

Regulations & Operator Certification

15% of exam · 2 questions

Safe Drinking Water Act requirements, EPA and primacy agency rules, MCLs, reporting, operator certification and renewal.

Distribution Operation & Maintenance

22% of exam · 2 questions

Mains, valves, hydrants, storage, meters, flushing, main breaks, repairs, and cross-connection control.

Disinfection & Chlorine Residual

15% of exam · 1 questions

Chlorine forms, breakpoint, residual monitoring, CT, disinfection byproducts, new main disinfection.

Hydraulics, Pumps & Pressure

15% of exam · 1 questions

Pressure and head, friction loss, water hammer, pump types, curves, and controls.

Sampling & Water Quality

13% of exam · 1 questions

Coliform sampling plans, lead and copper, chain of custody, taste and odor, nitrification, flushing for quality.

Safety

10% of exam · 1 questions

Trenching and shoring, confined space, traffic control, chlorine handling, lockout/tagout, PPE.

Distribution Math

10% of exam · 2 questions

Volume, flow, velocity, dosage, detention time, pressure conversions, disinfection and flushing calculations.

Math drills included

Pipe Volume

Find the gallons held in a length of main.

Tank Volume

Find the gallons in a cylindrical storage tank.

Chlorine Dosage

Pounds per day of chlorine needed for a dose and flow.

Detention Time

Time water spends in a pipe or tank.

Flow and Velocity

Convert between flow and velocity in a pipe.

Pressure and Head

Convert between psi and feet of head.

Sample questions

A taste of the bank — answers and explanations included.

Which federal law authorizes EPA to set drinking water standards for public water systems?

A community water system is defined as a public water system that serves at least how many year-round residents?

The main purpose of unidirectional flushing is to:

A cross-connection is:

Free chlorine residual consists of:

Ready to start? It is free.