Becoming a California REHS: The Complete Beginner's Guide

Everything you need to plan the path from "I'm interested" to "I'm a Registered Environmental Health Specialist," with links to the full detail on every step.

If you're new to this, start with what an REHS actually does. This guide assumes you already know the basics and want the roadmap: what has to happen, in what order, before you're a licensed Registered Environmental Health Specialist in California.

Becoming an REHS runs through five stages: confirming you meet the eligibility requirements, applying to have your education evaluated, sitting for the exam, passing it, and completing your registration. Each stage has its own paperwork, timeline, and gotchas, which is why we've written full articles on each one. This page ties them together so you can see the whole path before diving into any single piece.

The path in five minutes

• Decide. Confirm environmental health work (inspections, plan review, enforcement, and education across food, water, housing, and waste programs) is the career you want.
• Meet eligibility. Line up your coursework and experience against one of five CDPH pathways under Health and Safety Code Section 106635.
• Apply. Submit your transcripts for evaluation, apply to CDPH, and get approved to test.
• Pass the exam. Sit for the 260-question, two-booklet REHS exam covering all 17 content modules.
• Register. Pay the registration fee, receive your certificate, and start tracking continuing education for renewal.

None of these stages happens overnight. Between assembling transcripts, waiting on the evaluation, and studying for the exam, most candidates should plan on several months from a standing start, longer if coursework gaps need to be filled first.

Step 1: Eligibility (Options I–V)

California doesn't require one fixed degree. Instead, Section 106635 lays out five eligibility pathways, labeled Options I through V, that trade off basic science coursework against applied coursework and post-degree experience. More coursework buys down the amount of supervised experience and training hours CDPH requires before you're exam-eligible. Option V, a specific EHAC-accredited bachelor's degree, satisfies everything at once with no post-degree experience required.

The table looks intimidating at first glance, but it collapses into two variables once you understand it. Read the full breakdown in REHS Options I–V Explained.

Already certified in another state?

California doesn't automatically recognize REHS or sanitarian credentials from other states. Out-of-state candidates go through a separate Equivalency Determination process under Health and Safety Code Section 106725, which compares your existing credential and experience against California's standards. See REHS Reciprocity: How Out-of-State Certificate Holders Get California Equivalency for the full process, fees, and gating requirements.

Step 2: Transcript evaluation

Before CDPH will approve you to test, your college transcripts have to be evaluated against the Option you're pursuing. CDPH doesn't do this review itself. It's handled by CPS HR Consulting, a third-party agency that checks your coursework course-by-course against the eligibility table. This step sets the pace for your whole timeline, since you can't move forward until it's complete. Read The CPS HR Transcript Evaluation, Explained for what to send and what they're actually checking.

Step 3: Applying to CDPH

Once your transcripts clear evaluation, you'll assemble the rest of your application: documentation of your qualifying experience and training hours, the application fee, and any supporting forms CDPH requires. Our full walkthrough, How to Apply for the REHS in California, covers the sequence step by step, including current fee amounts to confirm on CDPH's site before you budget.

Step 4: The exam itself

The REHS exam is 260 multiple-choice questions, administered as two separate 130-question booklets rather than one continuous test, covering all 17 content modules from food protection and potable water through vector control, hazardous materials, and epidemiology calculations. It tests applied judgment and regulatory application at least as much as raw recall. Get the full format breakdown, timing, and question types in REHS Exam Format, Length & Question Types, and a module-by-module study map in REHS Exam: The 17 Modules You Need to Master.

Step 5: After you pass

Passing the exam isn't the finish line. You still need to complete registration with CDPH, pay the initial registration fee, and start tracking the continuing education requirements that keep your credential active. After You Pass: REHS Renewal & CE Guide covers the renewal cycle and what counts toward your CE hours.

How to actually study for this

Most candidates give themselves somewhere between eight and twelve weeks of dedicated study before their exam date, spaced out rather than crammed into the final two weeks. Our 12-Week REHS Exam Study Plan lays out a week-by-week schedule across all 17 modules.

Before you commit to a paid resource, it's worth testing your baseline against the free practice quiz: 451 real practice questions across all 17 modules, with an untimed Drill Mode and a timed Exam Simulation, free with no purchase or account required. It's the fastest way to see where you actually stand.

Common myths and mistakes worth knowing up front

Candidates walk into this process carrying assumptions that don't hold up. Some think a science degree is mandatory (it isn't, given the range of Options), or that California automatically honors out-of-state credentials (it doesn't). We've collected the most common ones, with the facts behind each, in 5 Myths About the California REHS Exam, Debunked.

If you'd rather budget for study materials before committing money, our honest rundown of what's actually free (CDPH's own guidance documents, the statute and regulation text, and our own free tools) versus what's worth paying for is in 8 Free Resources for California REHS Exam Prep.

The bottom line

The path runs through eligibility, transcript evaluation, application, the exam, and registration, in that order, with no shortcuts around any single step. Each one has its own timeline, and delays in the early steps (especially transcript evaluation) push back everything after it. Start there, and use the linked guides above for the detail on each stage as you reach it.