About this C-55 — Water Conditioning prep
This prep is built specifically for the C-55 — Water Conditioning examination and includes a 18,000+-word study guide written for this exam, 5 full-length practice exams and 500 practice questions, each with a written explanation.
The C-55 Water Conditioning trade examination is administered by CSLB / PSI. Closed book. 100 Q / 210 min. Pass % not published. Mix on/after 5/1/2024: Planning 28, Installation 24, Troubleshooting 31, Safety 17. C55StudyGuide.pdf. Not C-36. Not Law 115/73.. This prep is written to that board’s current scope, not to a generic national syllabus.
The real C-55 — Water Conditioning exam contains 100 questions. Our practice exams mirror that structure so the format is familiar before you sit it.
Topics covered
- 2 Interpreting a Water Analysis Report
- 3 Water Sampling and Laboratory Analysis
- 1 Title 24 and the California Plumbing Code
- 2 Scope of C-55 Work Under the CPC
- 1 When Required
- 2 Required Contract Provisions
- 3 Prohibited Practices
- 1 Overview
- 2 Preliminary Notice
- 3 Recording and Enforcement Deadlines
- 4 Stop Payment Notices
- 2 Contractor Discipline
- 4 Permit Requirements
- 5 Contract Pricing and Payment Schedules
- 7 CSLB Complaint Process
- 3 CPC Chapter 6 -- Water Supply and Distribution
- 3 Cross-Connection and Backflow Prevention
- 5 Drainage for Water Treatment Equipment
- 5 Annual Backflow Testing
- 1 Electrical Safety
How access works
You are paying for access length (30, 60, or 90 days). The study guide and four timed exams are the same on every term. Access starts when you enrol and works on any device for that term.
Not affiliated with or endorsed by any state licensing board or exam vendor. For exam-preparation purposes only.
What is actually on the C-55 exam
CSLB divides the Water Conditioning (C-55) examination into four sections. These weightings are the Board’s own, taken from the study guide it publishes for this classification — they are not our estimate:
| Section | Share of exam |
|---|---|
| Planning and Estimating | 28% |
| Water Systems Component Installation and Startup | 24% |
| Troubleshooting, Maintenance, Repair, and/or Replacement of Water Systems and Components | 31% |
| Safety | 17% |
The C-55 examination is closed book — no reference materials may be used during the test. Questions are multiple choice with four options, and there is no penalty for guessing, so leave nothing blank.
This is only half of what you sit. Every applicant also passes the separate Law and Business examination, which is not part of the C-55 paper and is weighted on its own outline. Budget preparation time for both.
Source: CSLB Water Conditioning (C-55) examination study guide. Contractor Pathway is an independent exam-preparation provider and is not affiliated with or endorsed by CSLB.