Wetlands and Stream Crossings FAQs

Providing detailed information about wetlands and shoreland regulations.

What is a wetland?

An area that, either through surface water or groundwater, is wet enough and wet for a long enough period of time, to support a predominance of vegetation that grows in saturated soil conditions. In order for an area to be deemed a wetland, all three (3) of the following must be present:

  • Hydric Soils – Soils that are saturated or flooded during the growing season sufficient to produce anaerobic conditions in the upper soil layers.
  • Hydrophytic Vegetation – Greater than 50% of the vegetation present is adapted for life in saturated soil conditions.
  • Hydrology – Evidence exists that demonstrates the soils in the area are inundated with water either permanently or periodically throughout the growing season.

Examples of wetlands include, but are not limited to: swamps, bogs, marshes, forested wetlands, wet meadows and vernal pools.

Helpful Documents:

NHDES does not provide wetland delineation services. To confirm the presence of a wetland on your property, we recommend contacting a NH Certified Wetland Scientist (CWS).


What areas are regulated under New Hampshire Wetlands Law?

A Wetlands Permit from the NHDES Wetlands Bureau is required for excavating, removing, filling, dredging or constructing structures within the following areas:


  • Wetlands, such as forested, scrub-shrub, emergent wetlands, marshes, wet meadows and bogs.
  • Surface waters, including the beds and banks of streams, rivers, lakes, ponds and tidal areas.
  • Upland Tidal Buffer Zone, which is the area extending landward 100 feet from the highest observable tide line. This area can contain wetlands, transitional areas, developed and undeveloped upland.
  • Prime Wetland Buffer, which is the duly-established, 100-foot upland buffer surrounding wetlands that have been municipally designated as Prime Wetlands and, at the time of their designation, a 100-foot upland buffer was required.
  • Sand Dunes, which is a hill or ridge of sand piled up by the wind and commonly found on the seacoast.
An illustration of a surface water, the surface water’s bank and the bed of the surface water.


What are the wetlands setbacks?

Under NH Wetlands Law, RSA 482-A, there are no setbacks. Many municipalities have more stringent standards and include wetlands buffers and setbacks. Several specific resource types in New Hampshire have buffers (added levels of protection) and, under RSA 485-A, there are setbacks when installing new septic systems.

  • Prime Wetlands: Under RSA 482-A:15, several municipalities in New Hampshire have designated Prime Wetlands.  Some municipally-designated Prime Wetlands have a 100-foot Prime Wetland buffer zone. Please use the NHDES Wetlands Permit Planning Tool to determine if a municipality has designated Prime Wetlands with or without 100-foot buffer zones.
  • Tidal Buffer Zone: The area extending landward 100 feet from the highest observable tide line. This area can contain wetlands, transitional areas, and developed and undeveloped upland.
  • Waterbodies Protected under the Shoreland Water Quality Protection Act (SWQPA): Under RSA 483-B, all lakes, ponds and impoundments greater than 10 acres, all 4th order and greater streams and rivers, all designated rivers and designated river segments, and all waterbodies subject to the ebb and flow of the tide are protected.

Under the SWQPA, there is a 50-foot primary structure setback and a 20-foot accessory structure setback for those accessory structures that are not water-access structures.

There are also limitations on removing vegetation adjacent to protected waterbodies and this is explained within the Vegetation Management for Water Quality fact sheet.

  • Septic Systems: Under RSA 485-A, the NHDES Subsurface Systems Bureau requires that new septic systems be installed at least 75 feet from wetlands that contain very poorly drained soils and 50 feet from wetlands having poorly drained soils.

When installing septic systems within the protected shoreland, refer to these setbacks .


What activities require a wetlands permit?

A permit from the NHDES Wetlands Bureau is required for excavating1, filling2, dredging3 and removing or constructing structures within areas jurisdictional under wetlands law (RSA 482-A).

Examples of common activities that require a NHDES Wetlands Permit include, but are not limited to:

  • Construction of roadways or driveways over wetlands or watercourses.
  • Installing new culverts over wetlands or watercourses.
  • Driving through wetlands and/or removing vegetation when soils are rutted or the roots of vegetation are disturbed.
  • Maintenance, repair or replacement of culverts, bridges, dams and other structures.
  • Logging activities within wetland areas.
  • Trail construction over wetlands or watercourses.
  • Utility inspection, maintenance and repair (electric, gas, water) within wetland areas.
  • Pond construction and maintenance dredging.
  • Beach construction or replenishment of beach sand.
  • Constructing and repairing boat houses.
  • Constructing and repairing breakwaters.
  • Construction, modification and repair of docking structures.
  • Installing watercraft lifts.
  • Construction repair or modification of any retaining wall within or adjacent to surface waters or wetlands.
  • Removing sand dune vegetation.


1 Excavating: digging, removing, or forming a cavity or a hole in an area within department's jurisdiction.
2 Filling: placing materials in or on a wetland, surface water body, bank or otherwise in or on an area within the jurisdiction of the department.
3 Dredge: to dig, excavate, or otherwise disturb the contour or integrity of sediments in the bank or bed of a wetland, a surface water body, or other area within the department's jurisdiction.



How do I determine temporary and permanent wetland impacts?

Temporary wetland impacts result from activities in jurisdictional areas that will be fully restored to pre-construction grades and conditions when the authorized work has been completed.

Temporary impacts often include, but are not limited to: areas excavated for burying utility lines; ruts caused by heavy machinery that are smoothed and restored when the work is completed; installing temporary equipment access ways; and installing temporary erosion and sedimentation controls.

Permanent wetland impacts result from activities in jurisdictional areas that are intended to remain, or that do remain, after the activities have ceased. These include jurisdictional areas that are altered, excavated, dredged or filled to a state that is irreversible. Permanent wetlands impacts include, but are not limited to: fill associated with a wetland or stream crossing, bridge abutments, culverts and excavation associated with ponds, ditches and channels.


How long is a wetlands permit valid?

With the exception of Forestry Statutory Permit-by-Notifications, Small Motor Mineral Dredging Permits, and 10-year wetlands permits issued to repair or replace shoreline structures, wetlands permits are valid for 5 years.

  • Forestry Statutory Permit-by-Notifications are valid for two years.
  • Small Motor Mineral Dredging permits expire at the end of the calendar year in which they are issued.
  • Wetlands permits issued to repair or replace shoreline structures to maintain their safety and integrity such as, but not limited to: docks, sea walls, breakwaters, riprap, access ramps and stairs that are damaged by storms or ice are valid for 10 years provided any work performed after the initial permitted work is completed meets the following conditions:
    • The original permit has not been revoked or suspended without reinstatement.
    • All structures are repaired or replaced to the original permitted location and configuration.
    • All significant work is reported to the department in accordance with the reporting requirements for the original permit.


Can a wetlands permit be extended?

With the exception of Forestry Statutory Permit-by-Notifications, Small Motor Mineral Dredging Permits, and 10-year wetlands permits issued to repair or replace shoreline structures, a single wetland Permit Extension not exceeding 5 years may be granted, provided the applicant demonstrates all of the following:

  • The permit for which the extension is sought has not been revoked or suspended without reinstatement.
  • The extension does not violate a condition of law (RSA 482-A) or rule Env-Wt 100-900.
  • The project is proceeding towards completion in accordance with plans and other documentation referenced by the permit.
  • The applicant proposes reasonable mitigation measures to protect the public waters of the state from deterioration during the period of extension.
  • The wetland delineation is still valid pursuant to NH Administrative Rule Env-Wt 406.01(b).

What is avoidance and Minimization?  

In order for a wetlands application to be approved, the applicant must demonstrate that all proposed impacts to jurisdictional resources have been avoided and minimized to the greatest extent practicable.

Avoidance means not impacting jurisdictional areas if there is an alternative that would have less impact, provided the alternative does not have other significant adverse environmental consequences. For example, using available upland areas to construct a driveway to a proposed single family residence as opposed to constructing the driveway through a wetland.

If jurisdictional resources cannot be avoided, then the impacts must then be minimized to the greatest extent practicable. Minimization means reducing the adverse impacts to jurisdictional areas using minimization measures. For example, if the wetland crossed the entire property and the buildable portion of the lot could not be accessed without crossing the wetland, then minimization measures could include constructing the crossing through the narrowest portion of the wetland; limiting the number of wetland/stream crossings to the minimum required to access the buildable portion of the lot; narrowing the driveway and side slopes through the wetlands to reduce the amount of fill required; and including the installation of culverts to promote hydraulic connectivity and aquatic organism passage within the wetland.

For more information on how to avoid and minimize impacts for a proposed project, review the Wetlands Permitting; Avoidance, Minimization, and Mitigation fact sheet as well as the Avoidance and Minimization BMP Manual.


What is mitigation and when is it required?

Mitigation is a way to ensure a project does not create a net loss of wetland functions and values. NHDES requires mitigation for projects that:

  • Will permanently impact a Priority Resource Area (PRA).
  • Will permanently impact 10,000 square feet or more of non-tidal wetlands.
  • Will permanently impact tidal surface waters, tidal wetlands, the tidal buffer zone, or sand dunes, or any combination thereof, unless otherwise specified in Rule Env-Wt 605.03(b).
  • Will alter the course of or disturb 200 linear feet or more of an intermittent or perennial non-tidal stream or river channel or its banks.
  • Involve the construction of a new Tier 3 or Tier 4 stream crossing unless otherwise specified in the Stream Crossing Rules, Env-Wt 900.
  • Involve the construction of a pond with more than 10,000 square feet of impact in a wetland or surface water.
  • Involve the installation of accessory docking structures or the construction of new shoreline structures and breakwaters, or includes such work in combination with other qualifying criteria, provided the resulting dock surface area of all shoreline structures on the frontage is 2,000 or more square feet.

To learn more about wetlands mitigation, visit the Wetlands Mitigation Program Page.


What is a Priority Resource Area (PRA)?  

Priority Resource Areas (PRAs) are jurisdictional areas that are considered to contain high-value wetland resources that warrant additional protections. In order for a wetland to be considered to be a PRA, it must meet one or more of the following criteria:

  • Has documented occurrences of protected species or habitat.
  • Is a bog.
  • Is a floodplain wetland contiguous to a tier 3 or higher watercourse.
  • Is a designated prime wetland.
  • Is duly-established 100-foot buffer of a designated prime wetlands.
  • Is a sand dune, tidal wetland, tidal water, or undeveloped tidal buffer zone.

The presence of a PRA within the vicinity of a proposed project may have an effect on project classification or mitigation requirements. Please read the Priority Resource Area fact sheet for more information.