Ohio's rule book is numbered to match its statute book on purpose. Chapter 3745 of the Revised Code is the chapter that created the state environmental agency, and every rule that agency writes begins with 3745 as well.
That mirroring is genuinely useful once you trust it. It is also the thing that will mislead you first, because it does not mean what most people assume.
Two books, one numbering habit
Statutes are the Ohio Revised Code. One code, not a shelf of separately named ones, split into 33 titles. The titles run in odd numbers from 1 to 63, with a single even one, Title 58, for trusts.
The section number tells you where you are standing. A chapter number opens with its title number, and a section number opens with its chapter. So 3745.01 is section 01 of chapter 3745, which sits in Title 37, Health-Safety-Morals. And 106.03 is section 03 of chapter 106, in Title 1. Once you see it you can place any Ohio section from the digits alone.
Agency rules are the Ohio Administrative Code. The Legislative Service Commission codifies both books and publishes them on the state's own site. Proposed and amended rules go through the Joint Committee on Agency Rule Review, which gets 90 days to look at a filing, and they appear in the Register of Ohio, which updates weekly.
Where the mirror stops
An administrative rule number opens with an agency number. That number matches, where it can, the Revised Code chapter the agency principally draws its rulemaking authority from. After it comes an optional division number behind a colon, then a chapter behind a hyphen, then the rule itself.
Read 3745-1-01 as agency 3745, chapter 1, rule 01. It is the purpose and applicability rule for Ohio's water quality standards. Read 109:4-3-09 as agency 109, division 4, chapter 3, rule 09.
Now the catch. The agency number follows the agency, not the subject. Rule 109:4-3-09 is a consumer protection rule about failing to deliver goods a shopper paid for. The statute behind it is Ohio's consumer sales practices chapter, R.C. Chapter 1345, in Title 13. The rule is numbered 109 because Chapter 109 of the Revised Code is the Attorney General. Go hunting for rules numbered 1345 and you will find nothing, and you will be wrong about the law.
So the mirror tells you who wrote a rule. It does not tell you which statute the rule is built on. For that, read the authority line printed with the rule.
The citation form is fussier than you would guess
Ohio's own Supreme Court publishes a writing manual, and it is stricter than most state styles.
- Statutes take no section symbol at all.
R.C. 3905.12. - Chapters and titles keep the abbreviation.
R.C. Ch. 2901.R.C. Title 29. - Rules take no section symbol either, and the manual tells you not to write the word section after Code.
Adm.Code 109:4-3-09. - The constitution does take one.
Ohio Const., art. IV, § 2(B)(1)(g).
Which means in a single paragraph you can be right to use the section symbol for a constitutional provision and wrong to use it for the statute sitting next to it.
Cases have their own habit. Since May 1, 2002 every opinion posted to the court's site carries a number the manual calls a WebCite, made of the year, the word Ohio, and a number unique to that opinion. State ex rel. Horton v. Kilbane, 2022-Ohio-205, ¶ 16-18. Pinpoints are paragraph numbers rather than page numbers, and the year lives inside the cite, so no parenthetical year follows it.
What the corpus looks like
These counts come from a US primary law corpus maintained by Vaquill AI, measured on 2026-09-18. Ohio holds 55,514 sections.
- Statutes: 33,158
- Regulations: 19,407
- Attorney General opinions: 1,406
- Court rules: 1,167
- Constitution: 265
- Agency guidance: 111
On the court rules, 963 are in force, 181 are superseded and 23 are reserved. The constitution carries 263 provisions in force and 2 repealed.
Every rule carries its own clock
Ohio does not let a rule sit quietly forever. Under R.C. 106.03 an agency has to go back through each of its rules before a stated review date and decide whether to keep it, amend it or rescind it. That review date cannot be set more than five years out from the day the rule took effect. And the date is printed with the rule, so it is something you can read rather than guess at.
Rule 3745-1-01 took effect on March 20, 2024 and carries a review date of March 6, 2028. It also lists prior effective dates going back to April 4, 1985. Rule 109:4-3-09 took effect on May 17, 2020 with a review date of May 7, 2030.
Watch the verb while you are in there. Ohio statutes get repealed. Ohio rules get rescinded. If you are filtering on status, rescinded is the word that matters on the rules side, and a filter built for another state will quietly miss it.
Try it on a bare number
Someone drops a number into a thread with no book named. Here is the order I would work in.
- Look at the punctuation before the digits. A period in the middle, like 3745.01, means a statute. Hyphens, like 3745-1-01, mean a rule. A colon near the front means a rule written by a division inside a larger agency.
- Place the statute from its own digits. Chapter 3745 sits in Title 37, so you already know the subject area before you open anything.
- On a rule, read the effective date and the review date printed with it. Those two lines tell you how settled it is.
- Read the authority line rather than assuming the matching statute number is the one being implemented.
Other places Ohio catches people
Older Ohio statutes were not R.C. numbers at all. The court's manual still keeps abbreviations for the General Code and for the Revised Statutes of 1880 to 1910, so a pre-1953 Ohio cite will look nothing like a modern one and will not resolve as one.
Opinions from before May 2002 have no WebCite, and for those the manual sends you to the official Ohio reports instead.
And colons are load bearing. 4901:1-7-01 is a Public Utilities Commission rule, and the colon is the division marker. Strip punctuation in a lookup key and you have merged two different addressing systems into one.
The next Ohio number that lands in your inbox, read its shape before you read its digits, because Ohio already told you which book it came from.
Facts used
| Claim | Value | Where from |
|---|---|---|
| Total Ohio sections of primary law | 55,514 | Corpus counts, 2026-09-18 |
| Statute sections | 33,158 | Corpus counts, 2026-09-18 |
| Regulation sections | 19,407 | Corpus counts, 2026-09-18 |
| Attorney General opinions | 1,406 | Corpus counts, 2026-09-18 |
| Court rules, in force / superseded / reserved | 1,167 total, 963 / 181 / 23 | Corpus counts, 2026-09-18 |
| Constitution provisions, in force / repealed | 265 total, 263 / 2 | Corpus counts, 2026-09-18 |
| Agency guidance documents | 111 | Corpus counts, 2026-09-18 |
| Revised Code titles, odd numbers 1 to 63 plus Title 58 | 33 | Ohio Revised Code title list |
| Chapter 3745 subject | Environmental Protection Agency, Title 37 | Ohio Rev. Code § 3745.01 |
| Chapter 109 subject | Attorney General, Title 1 | Ohio Rev. Code § 109.01 |
| Chapter 1345 subject | Consumer Sales Practices, Title 13 | Ohio Rev. Code § 1345.05 |
| Chapter 4901 subject | Public Utilities Commission, Title 49 | Ohio Rev. Code § 4901.01 |
| Agency number matches the Revised Code chapter the agency draws rulemaking authority from | Rule numbering system | Ohio rule drafting guidance on rule numbers |
| Rule 3745-1-01 subject | Purpose and applicability, water quality standards | Ohio Admin. Code 3745-1-01 |
| Rule 3745-1-01 effective date and review date | Effective March 20, 2024, review March 6, 2028 | Ohio Admin. Code 3745-1-01 |
| Rule 109:4-3-09 subject | Failure to deliver, substitution of goods or services | Ohio Admin. Code 109:4-3-09 |
| Rule 109:4-3-09 effective date and review date | Effective May 17, 2020, review May 7, 2030 | Ohio Admin. Code 109:4-3-09 |
| Agency must review each rule before its review date | R.C. 106.03 | Ohio Rev. Code § 106.03, Agency review of existing rules |
| Review date no later than five years after effective date | Five years | Register of Ohio, abbreviations and definitions |
| JCARR review window | 90 days | Joint Committee on Agency Rule Review |
| Register of Ohio updates weekly | Weekly | Register of Ohio |
| Statutes cited without a section symbol | R.C. 3905.12 | Supreme Court of Ohio Writing Manual, 3.1 |
| Rules cited without a section symbol or the word section | Adm.Code 109:4-3-09 | Supreme Court of Ohio Writing Manual, 4.4 |
| Constitution cited with a section symbol | Ohio Const., art. IV, § 2(B)(1)(g) | Supreme Court of Ohio Writing Manual, Section Two |
| WebCite in use since May 1, 2002 | 2022-Ohio-205 | Supreme Court of Ohio Writing Manual, 1.1 |
| General Code and Revised Statutes abbreviations still in use | G.C., R.S. (1880-1910) | Supreme Court of Ohio Writing Manual, 3.1 |
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