Building on Waterfront Property

Tree cutting, setbacks, docks, beaches, impervious surfaces, and everything else waterfront property owners need to know.

Sections:Three Zones Setbacks Tree Cutting Docks Beaches Impervious Accessory Structures Permits FAQ

Owning waterfront property in New Hampshire is one of the great privileges of living in the Lakes Region — but it comes with a regulatory framework that can surprise even experienced property owners. Nearly everything within 250 feet of the water's edge is regulated by the state.

Understanding the rules before you start saves time, money, and potential enforcement headaches. This guide walks through what you can build, where, and which permits you'll need.

The Three Zones

New Hampshire's Shoreland Water Quality Protection Act (RSA 483-B) creates a protected shoreland extending 250 feet from the reference line. Within that zone, three tiers apply — stricter as you get closer to the water.

Waterfront Buffer
0\u201350 ft

Woodland Buffer
50\u2013150 ft

Protected Shoreland
150\u2013250 ft

← Water's Edge (Reference Line)250 ft from water →

Zone	Distance	Key Restrictions
Waterfront Buffer	0–50 ft	Most restrictive. Primary structures prohibited. Tree removal governed by grid/point system. No ground cover removal (except one 6-ft footpath). Stumps and roots must stay. Only accessory structures allowed (20-ft min setback).
Woodland Buffer	50–150 ft	At least 25% must remain in unaltered natural state. Tree removal allowed but must maintain the unaltered percentage. Primary structures must be 50+ ft from water.
Protected Shoreland	150–250 ft	Impervious surface limits apply (20% standard, up to 30% with stormwater plan). No state tree-cutting restrictions beyond 150 ft. Alteration of terrain rules may apply for larger projects.

What's the “Reference Line”?

It's the starting point for all measurements. For lakes and ponds over 10 acres, it's the surface elevation on the NHDES Consolidated List. For rivers, the ordinary high water mark. For coastal waters, the highest observable tide line. Everything is measured horizontally from this line.

Setback Requirements

Before designing anything, know how far structures must be from the water. Towns can maintain setbacks greater than these state minimums but never less.

Structure Type	Min Setback
Primary structures (house, attached decks)	50 ft
Accessory structures (shed, patio, gazebo, retaining wall)	20 ft
Septic system — standard soils	75 ft
Septic system — restrictive layers within 18″	100 ft
Septic system — porous sand/gravel (perc ≤ 2 min/in)	125 ft
Well	75 ft from septic

Nonconforming Structures

Many older lakefront homes sit within the 50-ft buffer. These are “legally nonconforming” — they can be repaired, replaced in kind, or even expanded, but any expansion cannot move the structure closer to the water and must be made “more nearly conforming.” You cannot enclose a water-facing deck or porch to create new living space within the buffer.

Cutting Trees: The Grid & Point System

Probably the single most misunderstood rule on waterfront property. You can cut trees near the water — but it's not a free-for-all. The state uses a grid and point scoring system within the 50-ft waterfront buffer.

Starting from the northern or eastern property boundary, the buffer is divided into 25 ft along the shore × 50 ft inland grid segments. Each tree gets points based on trunk diameter at 4.5 ft above ground.

Tree Point Scoring (Trunk Diameter at 4.5 ft)

Trunk Diameter	Points
1–6 inches	1 point
6–12 inches	5 points
12–24 inches	10 points
Over 24 inches	15 points

The Rule

Trees may be removed from any grid segment as long as the remaining score stays at or above 25 points. If a segment already has fewer than 25 points, no trees can be removed. Planting native saplings in underperforming segments can enable future selective cutting.

Ground cover: No natural ground cover can be removed in the 50-ft buffer except for one 6-ft-wide footpath to the water. Stumps, roots, and rocks must stay. No vegetation under 3 ft can be cut (exception: existing lawns established before July 1, 2008).

Pruning: You can prune trees — removing lower branches to open up views while keeping the tree intact. Pruning only the bottom third is recommended. Often this achieves the view homeowners want without triggering any regulatory issues.

Beyond 50 ft: In the woodland buffer (50\u2013150 ft), at least 25% must remain in an unaltered natural state. Beyond 150 ft, no state tree-cutting restrictions.

Tip for Buyers

If the view matters, evaluate the tree situation before you buy. High point scores mean room for selective removal. A borderline property means your hands may be tied. A qualified shoreland consultant can score your grid segments before closing.

Docks: Frontage, Size & Permits

All new docking structures — seasonal and permanent — as well as boat lifts and jet-ski lifts require a wetlands permit from NHDES. Even changes to an existing dock require a permit.

How Frontage Determines What You Get

“Frontage” is the average of the straight-line distance between where your property lines meet the reference line and the actual shoreline distance measured along the water.

Avg Shoreline Frontage	Max Boat Slips
Less than 75 ft	No standard right — small dock (4×24 ft) case-by-case
75 ft	2 slips
150 ft	3 slips
225 ft	4 slips
Each additional 75 ft	+1 slip

A “boat slip” on Winnipesaukee = 25 ft long, 8 ft wide, 3 ft deep. On lakes under 10,000 acres = 20 ft long, 6 ft wide, 3 ft deep. A boat lift or jet-ski lift counts as one slip.

Standard Dock Dimensions

Lake Size	Seasonal Dock Max	Permanent Dock Max
Under 1,000 acres	6 ft × 30 ft	Not permitted (seasonal only)
1,000+ acres	6 ft × 40 ft	6 ft × 30 ft (where conditions require)

Permanent docks (pilings, cribs) are only permitted on lakes over 1,000 acres where wind/wave conditions prevent seasonal docks. Seasonal docks are always preferred.

Setbacks & Property Lines

Docks must be at least 20 ft from abutting property lines, including the imaginary extension of those lines over the water. No watercraft may extend past the imaginary property line. If you want to place a dock within 20 ft of a property line, you need a signed, notarized letter from the abutter.

Can You Build a Sandy Beach?

The Short Answer

You cannot create a traditional walk-in sandy beach that slopes into the water. That is prohibited. But you can build a “perched beach” with proper permits. And it's illegal to dump sand or create any beach without a permit from NHDES.

A perched beach is a sandy area set back from the water and separated by a low retaining wall (typically natural fieldstone). The sand sits in a contained basin with granite steps providing water access. The sand stays on your property and doesn't wash into the lake.

Why not a walk-in beach? Sand eroding into the lakebed smothers bottom-dwelling organisms, destroys fish spawning habitat, increases turbidity, and carries phosphorus that feeds algae growth.

Rule	Details
Permit required?	Yes — wetlands permit (RSA 482-A) + shoreland permit (RSA 483-B)
Maximum size	900 sq ft and/or 50 ft wide (or 20% of frontage, whichever is less)
Slope restriction	Only on slopes less than 25% grade
Location	Cannot be built in a wetland or priority resource area
Existing beach replenishment	Limited to 10 cubic yards, no more than once every 6 years
Sand type	Clean, washed beach sand (quartz-based, free of fine sediments)
Natural shoreline	Must remain intact — perched beach is set back from water

Impervious Surfaces: The 20% / 30% Rule

Anything that doesn't absorb water — rooftops, decks, patios, driveways, walkways, gravel parking — is capped within the 250-ft protected shoreland. On smaller waterfront lots, the 20% threshold can be reached quickly.

Impervious Coverage	What’s Required
Up to 20%	Permitted with standard shoreland permit
20%–30%	Requires a stormwater management plan designed to infiltrate increased runoff
Over 30%	Requires engineer-certified stormwater system + waterfront buffer vegetation must meet minimum point scores in all grid segments

A house, driveway, deck, and patio may push you close to or past the limit. Understanding your existing impervious coverage before planning any addition is essential.

Alteration of Terrain

Alteration of Terrain Permit (RSA 485-A:17)

Required when a project disturbs more than 100,000 sq ft (~2.3 acres) of contiguous terrain. Within the protected shoreland, that threshold drops to 50,000 sq ft (~1.15 acres). Projects disturbing more than 2,500 sq ft on slopes of 25%+ within 50 ft of surface water may also trigger it.

Smaller projects still must follow erosion and siltation control practices during construction. All new structures within the protected shoreland must prevent surface runoff across exposed mineral soils.

Accessory Structures Near the Water

Sheds, patios, gazebos, retaining walls, stairs, and similar structures have their own set of rules within the waterfront buffer.

Rule	Standard
Minimum setback	20 ft from the reference line
Max size in waterfront buffer	150 sq ft and 12 ft tall (most accessory structures)
Total accessory area allowed	7.5 sq ft per linear foot of shoreline frontage
Water-access structures	Cannot exceed 50% of total allowed accessory area
Piped water	No accessory structure can be serviced by piped water
Footpath	One 6-ft wide path to water allowed — does not count against area

Doing the Math

150 ft of frontage = 1,125 sq ft of total allowed accessory area (150 × 7.5). Of that, water-access structures (dock, beach, waterside patio) can be at most 562 sq ft. That budget covers every patio paver, every retaining wall, every shed. Plan carefully.

The Permits You'll Need

Shoreland Permit (RSA 483-B)

Most construction within 250 ft of public water

Required for new construction, modifications to impervious surfaces, and excavation/fill within the protected shoreland. Contact NHDES Shoreland Program at (603) 271-2147.

Wetlands Permit (RSA 482-A)

Structures in or on banks of surface waters

Required for docks, boathouses, boat lifts, beaches, retaining walls touching water, shoreline stabilization, and any excavation/fill within the bank. Application fee: $600 as of July 1, 2025.

Alteration of Terrain (RSA 485-A:17)

Large disturbance areas

Required for disturbing 100,000+ sq ft of terrain (50,000 sq ft within shoreland), or 2,500+ sq ft on steep slopes near water. File at least 30 days before work begins.

Local Building Permit + Zoning Approval

All construction

Required by your municipality regardless of state permits. Local rules may be more restrictive. Always check with your town planning board and building inspector first.

Minimum Lot Frontage

If you're subdividing waterfront land, no new lot can be created with less than 150 feet of shoreland frontage. Minimum lot sizes are determined by soil type and septic requirements under RSA 485-A. Any subdivision within the protected shoreland requires DES subdivision approval.

Frequently Asked Questions

Can I clear my whole yard down to the water’s edge?

No. Within 50 ft of the water, natural ground cover must remain intact. You can maintain existing lawns established before July 1, 2008, but not expand them. Trees can only be removed if the remaining point score in each 25×50 grid segment stays at or above 25 points.

Can I use fertilizer on my waterfront lawn?

Only beyond 25 ft from the reference line, and only low-phosphorus, slow-release nitrogen fertilizer. Pesticide use is prohibited within 25 ft and may only be applied by a licensed applicator with a permit beyond that.

Can I remove rocks from the shoreline or lakebed?

Not without a permit. Rocks along the shoreline prevent erosion. In the lakebed, you may get a permit to relocate navigational hazards within a boat slip, but general removal is not allowed.

Can I put a fire pit near the water?

A fire pit within the 50-ft buffer is an accessory structure subject to the 20-ft setback, the accessory area calculation, and ground cover preservation. Check local fire code too — many towns have additional restrictions.

My lot has less than 75 ft of frontage. Can I get a dock?

There’s no automatic right under 75 ft, but a small dock (4×24 ft) can usually be permitted case-by-case. You’ll likely need abutter consent since the dock will be within 20 ft of a property line.

Does a deck count as impervious surface?

Yes. Decks, patios, rooftops, driveways, walkways, and gravel parking are all impervious surfaces under the Shoreland Protection Act. They all count toward the 20%/30% threshold.

Can I build a retaining wall along my shoreline?

Possibly, but it requires a wetlands permit and the state strongly prefers vegetative stabilization first. A retaining wall can only be built if stabilization can’t be achieved through planting vegetation alone.

What happens if I do work without a permit?

NHDES or your municipality can issue a notice of violation, enforcement order, or fine. You may be required to restore the property at your expense. Restoration almost always costs more than doing it properly with permits.

Who do I call to figure out what I need?

Start with NHDES at (603) 271-2147 and ask for the Inspector of the Day. You can also email shoreland@des.nh.gov. The NHDES OneStop Map Viewer helps determine if your property is in the protected shoreland.

Key Resources

Resource	What It's For
NHDES Waterfront Development	Overview of all waterfront permits and programs
NHDES Protected Shoreland	Shoreland permits, guidance, vegetation management
Docking Structures & Stabilization	Dock permits, registration, fact sheets
Docks in Non-Tidal Areas FAQ	Frontage, slip limits, permanent vs. seasonal
NHDES Land Development	Alteration of Terrain permits and stormwater guidance
NHDES Shoreland / Wetlands Bureau	(603) 271-2147 or shoreland@des.nh.gov
NH Lakes — Lake-Friendly Shoreline Actions	Best practices for maintaining a healthy shoreline

Buying or Building on the Water?

The rules that protect these lakes and rivers also protect the value of your property. Whether you're evaluating a property, planning a renovation, or figuring out if you can put a dock in, having an experienced guide makes all the difference.

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Important Disclaimer

This guide is for informational purposes only and is not legal advice. Waterfront development involves overlapping state and local regulations that vary by municipality. State permit fees and thresholds reflect rules current as of March 2026. Always consult with NHDES, your local planning board, and qualified professionals.