Wastewater Infrastructure Projects

Wastewater project resources for design planning and construction from inception to completion.

NHDES has the responsibility of reviewing design plans, technical specifications and supporting documentation for all new or modified public and private wastewater collection systems and municipal wastewater treatment systems.

All proposed public and private wastewater infrastructure projects, whether new construction or replacement, must be submitted to the Wastewater Design Review Section for review and approval prior to construction in accordance with Env-Wq 700.

For large wastewater infrastructure projects, it is recommended to engage the Wastewater Design Review Section early in the planning stages.

Sewer Connection Permit

Prior to the start of construction, a Sewer Connection Permit request must be submitted and approved for any project that proposes to construct or modify:

  • Any extension of a collector or interceptor, whether public or private, regardless of flow.sewer manhole cover
  • Any wastewater connection or other discharge in excess of 5,000 gallons per day.
  • Any wastewater connection or other discharge to a wastewater treatment facility operating in excess of 80% design flow capacity or design loading capacity based on actual average flow or loadings for 3 consecutive months.
  • Any industrial wastewater connection or change in existing discharge of industrial wastewater, regardless of quality or quantity;
  • Any sewage pumping station greater than 50 gpm or serving more than one building.
  • Any sewer that serves more than one building or that requires a manhole at the connection.
Apply for a Sewer Connection Permit


Designing for Efficiency

The most cost-effective method to achieve energy efficiency is to make energy efficiency measures an integral part of the design for new and upgraded WWTFs and pumping stations.


Standard Front End Documents 

NHDES through its Wastewater Engineering Design Review Section has prepared a Standard Front End Rebar skeleton of building being constructedpackage for use in preparing bidding documents for State Revolving Fund (SRF) projects and to maintain eligibility for State Aid Grant (SAG) funds. The Standard Front End is broken down into the following sections:   

  • Section A: Bidding Requirements; Customizable for different funding programs.  
  • Section B: Contract Documents  
  • Section C: Joint General Conditions, changes cannot be made to this section.  
  • Section D: SRF Federal Provisions, only required when the project is funded through the SRF.  

Standard Front End Documents   

an image of a wastewater treatment plant

Standard State Contracts 

Standard State Contracts for report, design and construction phase engineering services must be used for CWSRF-funded projects and to maintain eligibility for receiving State Aid Grant funds. These contracts must be reviewed and approved by NHDES prior to execution by the project owner and pre-qualified engineer.  

Standard State Contracts  

an image of a wastewater tank

Operation and Maintenance Manuals 

Every wastewater project must have an NHDES-approved Operations and Maintenance Manual, no matter the funding source.    

Learn more about the O&M Manual  

Engineering Prequalification

Any consulting engineering firm that intends to compete for engineering contracts for municipal wastewater or drinking water projects that are to receive federal or state funding assistance must be prequalified, per Env-C 500. The intent of the Prequalification Program is to ensure that the firms have the experience and capability to satisfactorily complete these contracts. NHDES maintains a roster of these engineers for the public.  

Prequalified Engineers Apply or Renew
Design Review Engineer
Design Review Engineer
Construction Management Engineer
Construction Management Engineer
Design Review Engineer