Welcome to the State Water Resources Control Board Welcome to the California Environmental Protection Agency
Governor's Website Visit the Water Board Members Page
My Water Quality
Performance Report

1,2,3,-Trichloropropane Maximum Contaminant Level

Notices and Announcements

  • Click here for the Notice of Proposed Rulemaking for 1,2,3-Trichloropropane (1,2,3-TCP) Maximum Contaminant Level (MCL) Regulations
  • Click here for the State Water Resources Control Board (State Water Board) Notice of Public Hearing, Notice of Intent to Adopt a Mitigated Negative Declaration, and Opportunity for Public Comment
  • Click here for procedures for the hearing, including limits on speaker time and requirements for submitting power point presentations in advance of the hearing. To ensure a productive and efficient public hearing in which all participants have opportunity to participate, oral comments and any presentations will be limited to no more than three (3) minutes, and may be further limited at the discretion of the Board Chair or any Board member present

Important Dates and Information

The written public comment period for the proposed 1,2,3-TCP MCL regulations will begin on Saturday, March 4, 2017 and end at 5:00 p.m., Friday, April 21, 2017.

The State Water Board will hold a public hearing during which public comments may be made verbally or submitted in writing at 9:00 a.m., Wednesday, April 19, 2017 at the following location:

Joe Serna Jr. - CalEPA Headquarters Building
Coastal Hearing Room
1001 I Street, Second Floor
Sacramento, CA 95814

Additional information regarding the public comment period, including how to request a copy of pertinent documents and how to submit written comments, is provided in the notices linked above.

Description of Proposed Regulations

The primary purpose of the proposed regulations is to adopt a primary drinking water standard of 0.000005 milligrams per liter for 1,2,3-TCP in drinking water, consistent with and meeting the requirements of Health and Safety Code section 116365, and supporting regulations, including setting a Detection Limit for purposes of Reporting and identifying the Best Available Technology.

The proposed regulations will also establish a method for public water systems to substitute existing water quality data to meet initial monitoring requirements under certain conditions.

Sections Affected

California Code of Regulations, Title 22, Sections 64444, 64445, 64445.1, 64447.4, 64465, and 64481.

Rulemaking Documentation

California Environmental Quality Act (CEQA) Information

Peer Review Documentation

Major Regulations Documentation

Documents Relied Upon

The documents below are numbered in the order used in the Initial Statement of Reasons. For clarity only the document numbers are provided; please refer to the Initial Statement of Reasons for document dates and titles. Also note that Document 14 is a database that cannot be transmitted electronically; the same data may be obtained from Drinking Water Watch, and a link has been provided in the table below. All documents are in PDF format.

Document 1 Document 2 Document 3 Document 4 Document 5 Document 6
Document 7 Document 8 Document 9 Document 10 Document 11 Document 12
Document 13 Document 14 Document 15 Document 16 Document 17 Document 18
Document 19 Document 20 Document 21 Document 22 Document 23 Document 24
Document 25 Document 26 Document 27 Document 28 Document 29 Document 30

Contact Information

For more information please email DDW at ddwregunit@waterboards.ca.gov or contact:

Kim Niemeyer
Office of Chief Counsel
(916) 341-5547


Zachary C. Rounds, P.E.
Regulatory Development Unit
Division of Drinking Water
(707) 576-2733


Conny Mitterhofer, P.E.
(916) 341-5720




(Updated 3/13/17)