Culvert Maintainer FAQ

  • Certified individuals may maintain, repair, replace, or modify culverts up to a maximum diameter of 48'', or the hydraulic equivalent without prior DES permit
  • All maintained culverts must be able to pass flow without causing damage to upstream or downstream properties
  • All performed maintenance must be in accordance with NHDOT Best Management Practices for Routine Roadway Maintenance

  • Work on culverts with a history of overtopping
  • Work on double culverts regardless of diameter
  • Slip lining or other methods which reduce the diameter of the culvert
  • Historical culverts

For these scenario please file a routine roadway permit BEFORE performing work or contact DES for specific questions and instructions. 
Visit NHDES for more information on some roadwork permits

  • Municipal or state employees who have successfully completed approved Culvert Maintainer Certification training and passed the exam may apply to NHDES to be certified.
  • NH Licensed Professional Engineers who are employed by or performing services for the state or NH municipalities.

**NH Licensed PE's May Apply For Certification Without Taking The Training Course**

Eligible individuals (see above) need only fill out this DES application. There is no fee for application.

Information about the initial certification period, and renewal certification period, is found here.

  • Recertification in 2023 will incorporate a review of whether the required quarterly reports have been submitted in the year prior, effective with the first quarterly report of 2022!
  • All CCMs must submit either the Paper or Electronic quarterly report form to DES detailing their maintenance activities for that quarter. If submitting by paper, the quarterly report form should be mailed as a hard copy (OR) scanned and uploaded as an attachment to CCM@des.nh.gov. The electronic form is completed online directly and no action is required through the mail or email.

IMPORTANT: NHDES will not be accepting emails sent directly to CCM@des.nh.gov where the content of the email states whether there has been no activity, or where the email body includes information about reporting activity. CCMs must continue to report quarterly, even when there is no activity, but this information needs to be filled out on the official Quarterly Report form. The Quarterly Report form (noting any activity, or no activity) can be mailed, completed online, or if a CCM chooses to use the CCM@des.nh.gov email for submitting the report, can attach the completed report to an email to CCM@des.nh.gov.


January 1 - March 31: reports due by April 15

April 1 - June 30: reports due by July 15

July 1 - September 30: reports due by October 15

October 1 - December 31: reports due by January 15

Regarding the photos:

Four photos are requested and encouraged with each report item: 1 upstream “before” photo, 1 upstream “after” photo, 1 downstream “before” photo, and 1 downstream “after” photo. Each should be dated and labeled, two per 8½ x 11 sheet if you’re scanning or mailing them, or titled with date and location if emailing.

  • CCMs must continue to report quarterly, even when there is no activity, and this information needs to be filled out on the official Quarterly Report form.  The quarterly report form (noting any activity, or no activity) can be mailed, completed online, or if a CCM chooses to use the CCM@des.nh.gov email for submitting the report, can attach the completed report to an email to CCM@des.nh.gov.
  • A quarterly report must be submitted for each CCM, whether there has been activity or not.  
    • Towns can submit paper forms for a group of CCMs at once, as long as there is one paper form submitted PER CCM, PER QUARTER.  Each individual CCM must have a report submitted (noting any work completed, or no work completed) each quarter. 
    • Towns submitting quarterly reports online via the electronic form can complete multiple quarterly reports one by one, by filling out the quarterly report form at onlineforms.nh.gov account more than once (once for each CCM), as long as they are submitting one electronic form per CCM per quarter.
    • Towns may not submit quarterly reporting information for multiple CCMs on one form.

You can complete the quarterly report form online completely digitally. We put together a video showing how to register with the NH State Forms system, and how to access and utilize the CCM application and quarterly report forms. 

Alternatively, you can email the completed Quarterly Monitoring Report and associated photos to CCM@des.nh.gov.  However, you must attach the actual Quarterly Report Form to the email.  IMPORTANT: NHDES will not be accepting emails sent directly to CCM@des.nh.gov where the content of the email states whether there has been no activity, or where the email body includes information about reporting activity. CCMs must continue to report quarterly, even when there is no activity, but this information needs to be filled out on the official Quarterly Report form. The Quarterly Report form (noting any activity, or no activity) can be mailed, completed online, or if a CCM chooses to use the CCM@des.nh.gov email for submitting the report, can attach the completed report to an email to CCM@des.nh.gov.

No, slip-linings may not be used under the certification program. Slip-lining should use the Routine Roadway Maintenance permit and consult a licensed engineer.

No, this is not acceptable under the certification program. Any scenario which involves multiple culverts should use the Standard Routine Roadway Notification process and employ the services of a licensed engineer.

This certification applies to 48” diameter culverts or their hydraulic equivalent. For box culverts the equivalent cross sectional area (1810 in2 ) may be used. Certified individuals should be clear that cross sectional area should be calculated using interior dimensions. In the image below the “span” should be multiplied by the “rise” .

CCM dimensions example image

Examples of maximum acceptable dimensions are below:

Dimensions Thickness Interior Area
Ft In In2
3 x 2 4 448
3 x 3 4 784
4 x 2 5 532
4 x 3 5 988
4 x 4 5 1444
5 x 3 6 1152
5 x 4 6 1728
6 x 3 7 1276

This is part of the existing Routine Roadway Maintenance rules. Extending culverts beyond 10’ can present significant new impacts to upstream and downstream channels. Extensions beyond 10’ should use the Routine Roadway Maintenance permit and consult a licensed engineer.