Read this first. This page is a plain-language summary written for orientation. It is not legal advice, it is not a permit, and it cannot account for the specifics of your property. Prime wetlands, shoreland conditions, existing structures, local ordinances and conservation commission requirements can all change the answer. NHDES administers these rules and is the authority.
Everything in the Water Is Regulated
The single most common misunderstanding in this subject is that “seasonal” means “unregulated.” It does not.
Wetlands permitting applies to all new docking structures and modifications of docking structures — seasonal and permanent — and to all boat and jet-ski lifts.
Docks in New Hampshire sit under two regimes at once: RSA 482-A, the wetlands statute administered by the NHDES Wetlands Bureau, and RSA 483-B, the Shoreland Water Quality Protection Act. A project generally has to satisfy both, and neither replaces whatever your town requires.
What varies is not whether you need authorisation but which route you take to get it. There are three, and the difference between them is substantial in both time and cost.
Seasonal Dock Permit by Notification
The simplest route, available under RSA 482-A:3, IV-a for seasonal docks that meet a specific set of criteria. If your project qualifies, this is a far lighter process than a full application.
The published criteria are, broadly:
- The dock is on a lake or pond
- It is the only docking structure on that frontage
- It is constructed to be removed, and is removed for at least five months each year
- It is narrow, rectangular and perpendicular to the shoreline
- It is on a parcel with 75 feet or more of shoreline frontage
- It is no more than 6 feet wide, and no longer than 40 feet on a waterbody of 1,000 acres or more, or 30 feet on a smaller one
- It sits at least 20 feet from an abutting property line, or the imaginary extension of that line
- Installation requires no modification, regrading or re-contouring of the shoreline — including no concrete pad for a hinged dock
- It complies with RSA 483-B, the Shoreland Water Quality Protection Act
- It is not in or within 100 feet of a municipally designated prime wetland
Size follows the waterbody. On waterbodies of 1,000 acres or larger, a qualifying seasonal dock may be up to 6 feet wide by 40 feet long. On a waterbody under 1,000 acres the same dock is limited to 6 feet wide by 30 feet long. Either way the parcel must carry 75 feet or more of shoreline frontage — that is one of the criteria itself, not merely a size allowance.
Criteria and both length allowances per RSA 482-A:3, IV-a, cross-checked against the NHDES seasonal dock notification form for lakes and ponds (NHDES-W-06-035), which carries the department’s list of waterbodies over 1,000 acres.
Two things people miss. First, the five-month removal is a condition of the authorisation, not a suggestion — a dock that stays in has stopped meeting the basis on which it was allowed. Second, a notification does not relieve you of the obligation to obtain other local, state or federal permits that may apply to your property.
Standard Wetlands Permit
The full application. You are here if the project is permanent, if it exceeds the seasonal criteria in any respect, or generally if it expands beyond an existing footprint.
Permanent docks are narrowly available
This is the threshold most people are unaware of, and it decides a great many projects before they begin:
Permanent docks may be permitted only on lakes larger than 1,000 acres, and only in areas where wind or wave conditions may prevent the use of a seasonal dock.
Both halves matter. The 1,000-acre threshold rules out permanent structures on smaller waters entirely — in our service area that means Lake Waukewan, the Suncook Lakes and Webster Lake, among others. And on the larger lakes, the burden is on demonstrating that a seasonal dock would not work at your frontage — not merely that you would prefer something permanent.
Where a permanent dock is possible, the published maximum standard dimensions are 6 feet by 30 feet on a waterbody of 1,000 acres or more with 75 feet or more of frontage — notably shorter than the 6 by 40 the same water allows a seasonal dock. Below 75 feet of frontage the maximum is 4 feet by 24 feet.
That 4 by 24 dimension applies on any water, but it does not make a permanent structure available where one is otherwise prohibited. On lakes and ponds under 1,000 acres, the NHDES dimensions table marks both the sub-75-foot and the 75-foot-plus allowances seasonal only; permanent structures are prohibited there regardless of how small the dock is.
Frontage governs slip count as well as size: a property needs 75 feet of shoreline frontage for a private dock with up to 2 boat slips, and a further 75 feet for each additional slip or securing location.
Shoreline frontage is an average, not a walk along the beach
NHDES defines shoreline frontage as the average of two lengths: the straight line drawn between the points where the side property lines intersect the reference line, and the length of the natural frontage between those same two points. On a straight shore the two are nearly identical. On an indented cove they are not, and the number that decides whether you clear 75 feet is the average of them — not the distance you pace out along the water’s edge.
Shoreline frontage definition per NHDES — Docks in Non-Tidal Areas FAQs, retrieved 5 October 2026.
Maximum standard dock dimensions per NHDES — Docks in Non-Tidal Areas FAQs, retrieved 28 September 2026.
Expect months, not weeks. This is why we tell people to start a new dock conversation in autumn for the following summer. The construction is rarely the constraint.
Voluntary Non-Tidal Dock Registration
The least known of the three and, for owners of older structures, frequently the most useful.
NHDES operates a voluntary registration for existing, legal, non-tidal docking structures. Once a registration is accepted, the registered structure is exempt from the requirement to obtain future NHDES repair or replacement permits for the duration of the registration. The statutory fee is $300, and the process is simpler and less expensive than the notification, expedited or standard permitting routes.
Two details in the statute are worth knowing before you rely on one. First, the registration is valid for 5 years or until ownership of the property changes, whichever occurs first — it does not pass to a buyer, so a registration quoted during a sale is of no use to the purchaser. Second, eligibility does not require a permit at all: a structure qualifies if it was constructed and maintained under a permit or has been maintained in its current size, location and configuration since 1 January 2000, was not built to make land in public waters, and is not the subject of a pending or final adverse compliance action.
NHDES has 10 business days to accept a registration filing or reject it. If it does not respond, the owner may submit a written request; if there is still no response within a further 5 days, the registration is deemed complete and the work may proceed as filed.
Fee per RSA 482-A:3, I(d); eligibility, term and the 10-day mechanism per RSA 482-A:3, IV-a(b)–(d). Retrieved 2 October 2026.
If you own an older dock that you expect to maintain and repair over the coming years, this is worth understanding. It converts a series of future permitting questions into one process now.
The load-bearing word is legal. Registration is for structures that were properly authorised. If a dock was never permitted, that is a different conversation and one worth having deliberately rather than discovering during a repair.
Repair in Kind vs. Reconstruction
On older structures this is the question that should be settled before anyone orders materials, and it is settled far too often afterwards.
Repair in kind of an existing legal structure — replacing deteriorated components with equivalent ones, in the same footprint — sits in a different regulatory position from reconstruction or expansion. An existing legal dock may carry a status that a replacement would not inherit, which means a decision made casually on site can have consequences that outlast the dock itself.
The practical advice is simple: if you have an older dock and you are contemplating anything beyond swapping boards, establish first whether what you are planning is repair or reconstruction, and what the structure's existing status actually is. That is a conversation, not a form, and it is considerably cheaper than the alternative.
Where NHDES Actually Draws the Line
The department publishes two narrow situations in which work on an existing legal dock does not require a wetlands permit, and both turn on the same two things: the footprint, and the waterline.
Changing materials only. If you are changing nothing but construction materials, no wetlands permit is required provided all three of these hold: you avoid changing the size, location or configuration — the footprint — of the dock; at the time of repair you avoid work on any portion of the structure below the water surface; and no work is in a tidal area. The published examples are replacing wood decking with composite, and replacing a wooden seasonal dock with an aluminium one.
Work in the dry. Separately, some repairs do not require a wetlands permit if they are on portions of a dock that are exposed — “in the dry” — and the lakebed is not disturbed. Repairs that change the footprint require a permit regardless.
Read together, the rule is legible: the waterline is a regulatory boundary, not merely a practical one, and before you change the size, location or configuration of an existing legal dock you need a wetlands permit whatever the job is called. The same repair is not necessarily the same permitting question on a dock standing in the water as on one pulled up on the shore.
Both exemptions and their conditions per NHDES — Docks in Non-Tidal Areas FAQs, retrieved 28 September 2026.
When Is an Old Dock “Legal”?
All of the above rests on the structure being legal, and on an older dock that is rarely obvious. NHDES publishes the test. A docking structure may be recognised as legally existing if it was in place before the start of any legal requirement to obtain a state permit, and it has been continuously maintained with no change to its location, size and configuration (or is a legal replacement structure), has not been abandoned for more than five years, is consistent with the public’s right to reasonable use of public waters, and is not built on land created by unauthorised filling of public waters.
The dates that decide “before the requirement” are published and specific. Permitting started:
- 2 July 1969 for freshwater permanent docking structures
- 4 September 1978 for freshwater seasonal docking structures
- 22 June 1967 for docking structures adjacent to tidal waters
So a crib standing unchanged since the 1950s, and a seasonal dock first installed in the mid-1970s, can both be legally existing without anyone in the chain of ownership having ever held a permit. The word carrying the weight is unchanged. An undocumented enlargement somewhere in that history is what breaks the claim — and it is usually discovered during a repair, which is the worst moment to discover it.
Criteria and commencement dates per NHDES — Docks in Non-Tidal Areas FAQs (“Can I ‘grandfather’ a dock?”), retrieved 28 September 2026.
Construction Type Is Decided by Rule, Not by Preference
Most owners assume dock type is a matter of taste and budget. The wetlands rules treat it as a conclusion that has to be justified, and they set the test out directly: a docking structure cannot be approved unless the applicant demonstrates that the type of construction proposed is the least intrusive upon the public trust that will ensure safe docking on the frontage.
What counts as seasonal, and what counts as permanent
The categories turn on whether the supports come out — not on material, and not on buoyancy.
- Seasonal dock — designed and constructed such that the structure and all associated supports can be completely removed from the surface water and its bed during the non-boating season. The term includes pipe docks and floating docks
- Permanent dock — one in which the docking structure or its supports, or both, are designed to remain in place throughout the year
- Float — not a type of dock but a component of a docking structure supported by buoyancy devices
- Crib — an enclosure or framework of durable material such as timber or prefabricated concrete, securely fastened and filled with inert ballast such as stone, used to support a docking structure in the water
- Ice cluster — two or more pilings installed closely together near the lakeward end of a docking structure to protect it from ice damage
The consequence is one people meet the hard way: a floating dock is a seasonal structure, but a float left in year-round with its anchors is a permanent one in regulatory terms, and permanent structures are narrowly available.
The wind-and-wave test is a number, not a judgement
Permanent docks require a water over 1,000 acres and exposure to a design fetch of at least 1 mile between compass headings 245 to 340 degrees, or at least 2 miles between headings 341 to 0 or 0 to 244 degrees, measured from true north. “Design fetch” is itself defined as the average of at least 11 radials evenly distributed across a 30 degree arc — an average across an arc, not the longest open sightline down the lake.
Where the fetch test is not met, a permanent structure may still be approved on documented wave activity: waves of at least one foot measured trough to crest, in water at least 3 feet deep at the proposed location, on at least 4 separate occasions lasting 4 hours each, between 15 May and 15 October — evidenced by dated photographs with heights, dates and frequency, or by site measurements verified by the department, taken often enough to show the activity was essentially continuous.
And three situations are approved regardless of design fetch: a structure on an island accessible only by watercraft; a structure subject to unusually heavy loading where a permanent structure is needed for safety; and a structure of significant public benefit, such as docking open to the public for transient use.
Open pile is the standard; a crib is an exception you evidence
This is the threshold that decides the shape of most permanent docks, and it is rarely explained to owners before they have chosen.
The standard design for a permanent docking structure shall be open pile construction.
Pile bents must be spaced at least 12 feet apart, centre to centre. Any other design is approved only where the applicant demonstrates both that pilings cannot be driven due to site conditions and that the alternative proposed is the least impacting design for that location. That demonstration must be submitted with the application and must include documentation of trial driving by commercial equipment, probings, or experience in the construction of immediately adjacent docks.
Where a crib is the approved alternative, its geometry is prescribed: a maximum of 6 feet by 6 feet in water up to 6 feet deep, with side dimensions increased by not more than one foot for every additional foot of water depth beyond 6 feet, and minimum clear spacing between cribs of 12 feet. A crib therefore broadens as the water deepens rather than simply standing taller. Alternatives other than a crib — caissons, concrete supports, prefabricated cofferdams — must be designed to standard engineering practice for the design proposed.
Seasonal timing, and the obligation that outlives the dock
- Seasonal structures on a lake or pond must be installed after ice-out and removed prior to ice-in
- They must be removed from the water before any paint, stain or preservative is applied, and not returned until it is dry
- If a permanent docking structure is not maintained so as to be usable for its intended purpose, the owner is required to remove it
- NHDES states that seasonal docks cause fewer lake impacts and do not require aerators for protection against ice damage
- A modification to an existing legal dock is approved only where it is less environmentally impacting, or provides fewer boat slips and less deck area, than the structure it replaces
Depth, slips and the 3-foot number
A boat slip is a defined volume of water: 20 feet long, 6 feet wide and 3 feet deep on waterbodies of 10,000 acres or less, and 25 feet by 8 feet by 3 feet on waterbodies greater than 10,000 acres — only Lake Winnipesaukee exceeds that size in New Hampshire. Depth is measured at the normal high water mark, and up to 2 feet of navigation space is allowed between a slip and any other slip or structure.
You cannot simply dredge your way to that depth. Permits may be obtained to relocate rocks that are navigational hazards — a rock qualifies if it is within a boat slip or the approach to a docking structure and within three feet of the water’s surface. Dredging of sediments, by contrast, can be permitted only in and around existing legal fixed structures that cannot easily be modified to attain the necessary depth.
Lifts, canopies and rafts
A boat lift or jet-ski lift needs a wetlands permit, and it counts as a slip. NHDES requires a permit for all boat lifts and jet-ski lifts, seasonal or permanent, and states that one boat lift or jet-ski lift is equivalent to a single boat slip. The rules then say where a lift may go: in an existing legal boat slip, or, for a personal watercraft lift, immediately adjacent to an existing legal docking structure. A seasonal lift follows the same timing as a seasonal dock — in after ice-out, out before ice-in. Where a lift is the only structure on the frontage, it must sit along the shoreline of the owner’s own property and meet every requirement for a seasonal docking structure.
The cheapest classification is reserved for a lift dropped into a slip that is already legal. NHDES classifies docking work as minimum impact, minor or major. A project limited to the installation of seasonal watercraft lifts within legally existing boat slips is a minimum impact project in its own right. Otherwise a seasonal project stays minimum impact only if, among other things, it proposes no more than 2 slips including any that already exist; up to 4 slips using no more than 100 feet of waterfront is a minor project.
Canopies are seasonal by rule, and their size limit follows the 1,000-acre line. A canopy over a boat slip needs a permit, and only seasonal canopies may be permitted. The canopy — frame and cover — must be readily removable at the end of the boating season, installed after ice-out and removed before ice-in, and must not obstruct lines of sight needed for navigation. A canopy cannot justify new permanent pilings, though an existing legal permanent structure may carry a seasonal canopy frame. A new canopy is a minimum impact project if it is the only canopy on the frontage and measures no more than 14 feet by 30 feet on waters of 1,000 acres or larger, or 12 feet by 25 feet on waters smaller than 1,000 acres; anything larger is classified with the dock it belongs to.
Swim rafts and moorings do not require the wetlands permit. They are not exempt from regulation — installing either must comply with the state laws and rules adopted by the Department of Safety, which runs the mooring program — but they are outside the dock permitting described on this page.
Lift permit requirement, lift-to-slip equivalence, canopy requirement, and the swim raft and mooring position per NHDES — Docks in Non-Tidal Areas FAQs. Accessory structures per Env-Wt 513.05; canopy design per Env-Wt 513.19; lift placement and the only-structure rule per Env-Wt 513.21; project classification per Env-Wt 513.24; canopy classification per Env-Wt 513.26. Retrieved 23 October 2026.
Two procedural points that cost people money
The fee is per square foot, and it doubles for permanent. A shoreline structure application costs $600 plus $6 per square foot of permanent dock surface area, $3 per square foot of seasonal dock surface area, and $0.60 per square foot of dredge or fill. A project involving only the repair, reconstruction or reconfiguration of an existing docking structure is a flat $600 regardless of area.
A permit must be recorded to work. Every permit granted for the installation, construction or repair of a dock must be recorded in the registry of deeds for the county where the property sits, and the permit is not effective until it is so recorded. An unrecorded permit is not a permit yet.
On setbacks, note also that the 20-foot distance from an abutting property line applies to all docking structures, not only to notification docks. It can be reduced with the signed and notarised written consent of the affected abutter, filed with the application; and abutters may jointly apply for a common dock on or near their shared line under a notarised agreement recorded at the registry of deeds. Docking structures may also be perpendicular, parallel, or at another angle to the shoreline depending on the needs of the landowner, safe navigation and the difficulty of construction — the strict perpendicular requirement belongs to the seasonal notification route, not to docks generally.
Approval criterion per Env-Wt 513.03(d); permanent dock criteria, wave alternative and exemptions per Env-Wt 513.04; setbacks and configuration per Env-Wt 513.10; dimensions per Env-Wt 513.11; frontage per slip per Env-Wt 513.12; navigation space per Env-Wt 513.14; pile and crib design per Env-Wt 513.15; seasonal timing and the maintenance obligation per Env-Wt 513.22; modifications per Env-Wt 513.23. Definitions of seasonal dock, permanent dock, float, crib, design fetch and ice cluster per Env-Wt 102.44, 102.52, 103.09, 103.19, 103.56 and 104.14. Fees per RSA 482-A:3, I(b); recording requirement per RSA 482-A:3, VI; setback consent and common docks per RSA 482-A:3, XIII. Boat slip dimensions, navigation space, the aerator position and the rock-relocation criteria per NHDES — Docks in Non-Tidal Areas FAQs. All retrieved 2 October 2026.
How Long Each Route Takes
New Hampshire does not leave this to departmental custom. RSA 482-A:3, XIV sets a processing clock with specific deadlines, and it governs every wetlands application except a permit by notification. What follows are statutory deadlines, not estimates of how busy the Wetlands Bureau is.
The seasonal notification has no decision period at all
A qualifying seasonal dock is not a permit that gets granted quickly. It is an exemption from permitting that you activate by filing a notice, which is a different thing in kind.
The rule that says so is Env-Wt 308.02, titled “Clarification of Statutory Exemptions.” Paragraph (i) places the seasonal dock there directly: as provided in RSA 482-A:3, IV-a, the installation of a temporary seasonal dock on any lake or pond is exempt from permitting, provided all requirements of RSA 482-A:3, IV-a are met, including filing a completed Form NHDES-W-06-035, Seasonal Dock Notification. Paragraph (j) does the same for the repair of a duly registered non-tidal dock.
So there is no review period to wait out and no approval letter to receive, and RSA 482-A:3, XIV(a) expressly excludes a permit by notification from the deadlines below. That cuts both ways. Nothing stands between you and the water except whether you actually qualify — and nobody at NHDES has confirmed that you do. The filing is a representation you are making, not a finding the department has made, which is why the criteria are worth getting right rather than nearly right.
Exemption and form reference per Env-Wt 308.02(i)–(j); exclusion from the processing clock per RSA 482-A:3, XIV(a). Retrieved 5 October 2026.
The standard application clock, step by step
For a full wetlands application the statute runs in stages, and each one has a deadline attached to it:
| Stage | Deadline | What happens |
|---|---|---|
| Administrative completeness | 10 days from receipt | NHDES issues a notice of administrative completeness, or tells you what is missing and who to send it to. Every time you send more information, the 10-day period starts again. |
| Your response deadline | 60 days from the notice | If the requested information does not arrive within 60 days, the department shall deny the application. An extension of this period is granted on request. |
| Technical review | 50 days (under one acre of jurisdictional impact) or 75 days (all other projects) | Measured from the notice of administrative completeness. By this point NHDES must request any further information it needs, with its technical comments. |
| Decision — information was requested | 30 days from a complete response | Approve, deny with written findings, schedule a public hearing within 30 days, or extend by written agreement with you. |
| Decision — nothing further requested | the same 50 or 75 days | The technical-review deadline doubles as the decision deadline where the department asks for nothing more. |
| Decision after a public hearing | 45 days from closure of the hearing record | Approve in whole or part, or deny with written findings. |
For a residential dock the 50-day figure is the one that applies. The 75-day band is for projects proposing an acre or more of jurisdictional impact; a dock is nowhere near that. So the realistic statutory floor on a straightforward full application is roughly two months from administrative completeness — and the ceiling is set by how many rounds of information requests the application invites, because each round restarts a clock.
If NHDES misses its deadline, you can get a permit by default
This is published, specific, and almost never mentioned to owners. If the department fails to act within the deadlines for a decision, you may submit a written request that it issue the permit. It then has 14 days to approve or deny. If it does neither within those 14 days, you are deemed to have a permit by default and may proceed with the project as presented in the application — and on written request NHDES will issue written confirmation that you hold one.
A permit by default is not a waiver of anything else. The statute is explicit that it does not relieve you of complying with every other applicable requirement, including water quality under RSA 485-A and federal requirements.
What legitimately stops the clock
- A significant amendment is treated as a new application, and the clock restarts. It means an amendment changing the permitted fill or dredge acreage by 20 percent or more, including a prime wetland, or elevating the project’s impact classification — but not an amendment made in response to the department’s own request
- An open enforcement action on the property allows review to be suspended, with extensions totalling up to 30 days
- A finding of non-compliance or material misrepresentation in the preceding 5 years allows an extension without your agreement, capped at 20 days
- The deadlines do not apply at all to an application filed after you have already done some or all of the work, or to a designated chronic non-complier. Building first does not merely risk enforcement — it forfeits the statutory timetable
- Extraordinary circumstances preventing the department from functioning suspend the timeframes until the commissioner determines the condition has ended
Separately, a granted permit is valid for 5 years, and NHDES shall grant one extension of up to 5 additional years where the stated conditions are met.
Your town can add up to 40 days, and the clock starts at the town clerk
The variable owners never price in is local. Where a municipal conservation commission — or a local river management advisory committee — notifies NHDES that it intends to investigate, the department shall not make its decision until it has received and acknowledged that body’s written report, or until 40 days from the date the notice was filed with the municipal clerk, whichever comes first.
Two details decide whether this affects you. The commission has to give notice of intent within 14 days of the filing with the municipal clerk; if it does not, NHDES does not suspend its normal action and proceeds as though no notification had been made. And for a permit by notification under RSA 482-A:11, VI-a the 40-day limit is reduced to 21 days, with intended investigation assumed unless the notification was signed by the conservation commission or, where none exists, the local governing body.
Note which date starts it: filing with the municipal clerk, not the day you filed with NHDES. Owners who leave the municipal filing until last are extending their own timeline without realising it.
Processing deadlines, permit by default, amendment and suspension provisions per RSA 482-A:3, XIV(a)–(g); permit duration and extension per RSA 482-A:3, XIV-a(a). Local investigation, the 40-day and 21-day limits and the 14-day notice window per RSA 482-A:11, III(a)–(b). Retrieved 5 October 2026.
A discrepancy worth knowing about. If you read these deadlines in the wetlands rules rather than the statute, you will see different numbers. Env-Wt 300, Appendix C reprints RSA 482-A:3, XIV with the 75-day and 105-day figures that preceded the current text, because the appendix has not been readopted since 2023 while the statute has been amended since — most recently effective 18 August 2026. The statute governs: RSA 482-A:3, XIV(b)(1) states that the time limits it prescribes supersede any time limits provided in any other provision of law. The operative figures are 50 and 75 days.
The Thresholds That Decide Most Projects
| Threshold | Value | What it governs |
|---|---|---|
| Waterbody size | 1,000 acres | Permanent docks only above it; also gates the seasonal size allowance |
| Shoreline frontage | 75 feet | A criterion of the seasonal notification in its own right |
| Frontage measurement | average of 2 lengths | The straight line between the side property lines, averaged with the natural frontage |
| Seasonal dock size | 6 ft × 40 ft | Maximum for a qualifying notification dock on a waterbody of 1,000 acres or more |
| Seasonal dock size | 6 ft × 30 ft | Maximum for a qualifying notification dock on a waterbody under 1,000 acres |
| Permanent dock size | 6 ft × 30 ft | Maximum on a waterbody of 1,000 acres or more with 75 ft+ frontage |
| Dock size below 75 ft frontage | 4 ft × 24 ft | Maximum standard dimensions where frontage is under 75 feet |
| Property line setback | 20 feet | All docking structures; reducible only with notarised abutter consent |
| Permanent dock design fetch | 1 mile / 2 miles | 1 mile between headings 245–340°, 2 miles elsewhere, from true north |
| Design fetch measurement | 11+ radials / 30° arc | Design fetch is the average across the arc, not the longest sightline |
| Pile bent spacing | 12 feet | Minimum centre-to-centre spacing on an open pile dock |
| Crib size | 6 ft × 6 ft | Maximum in water up to 6 ft deep; +1 ft per further foot of depth |
| Crib spacing | 12 feet | Minimum clear spacing between cribs |
| Boat slip depth | 3 feet | At normal high water; slip is 20 × 6 ft, or 25 × 8 ft above 10,000 acres |
| Frontage per boat slip | 75 feet | Up to 2 slips; a further 75 ft for each additional slip |
| Administrative completeness | 10 days | NHDES deadline to accept the application or state what is missing; restarts on each submission |
| Technical review / decision | 50 days | From administrative completeness, for projects under one acre of jurisdictional impact — every residential dock |
| Technical review / decision | 75 days | The same deadline for projects proposing one acre or more of jurisdictional impact |
| Decision after information request | 30 days | From NHDES receiving a complete response to its request |
| Decision after a public hearing | 45 days | From closure of the hearing record |
| Applicant response window | 60 days | Miss it and the department shall deny; an extension is granted on request |
| Permit by default | 14 days | After a written request following a missed deadline, silence means a permit by default |
| Local investigation hold | 40 days | From filing with the municipal clerk; 21 days for a permit by notification |
| Conservation commission notice | 14 days | Miss it and NHDES proceeds without suspending its normal action |
| Significant amendment | 20 percent | Change in fill or dredge acreage that makes it a new application, restarting the clock |
| Permit validity | 5 years | One extension of up to 5 further years shall be granted where conditions are met |
| Seasonal notification review | none | An exemption activated by filing, not a permit decided by the department |
| Application fee | $600 + $6 or $3 / sq ft | $6 permanent, $3 seasonal dock surface area; $600 flat for repair work |
| Registration fee | $300 | Voluntary non-tidal dock registration |
| Registration ends on sale | 5 years or transfer | Whichever comes first — it does not pass to a buyer |
| Alternative registration basis | 1 January 2000 | Unchanged in size, location and configuration since this date |
| Removal period | 5 months minimum | How long a seasonal dock must be out each year |
| Prime wetland buffer | 100 feet | Proximity to a municipally designated prime wetland disqualifies notification |
| Dock registration term | ~5 years | Exemption period from future repair/replacement permits |
| Abandonment | 5 years | Longer than this and a pre-permit structure is no longer recognised as legally existing |
| Freshwater seasonal permitting began | 4 September 1978 | Structures in place and unchanged since before it may be legally existing |
| Freshwater permanent permitting began | 2 July 1969 | The equivalent date for cribs and pile structures |
Which of our waters are over 1,000 acres?
| Water | Approximate size | Permanent dock possible? |
|---|---|---|
| Lake Winnipesaukee | ~72 sq mi | Yes, subject to the wind/wave test |
| Squam Lake | ~6,800 acres | Yes, subject to the wind/wave test |
| Lake Winnisquam | ~4,300 acres | Yes, subject to the wind/wave test |
| Newfound Lake | ~4,100 acres | Yes, subject to the wind/wave test |
| Lake Wentworth | ~3,000 acres | Yes, subject to the wind/wave test |
| Lake Waukewan | ~900 acres | Below the threshold — seasonal only |
| Pemigewasset Lake, Meredith | Below 1,000 acres | Below the threshold — seasonal only |
| The Suncook Lakes | Below 1,000 acres | Below the threshold — seasonal only |
Sizes are approximate and given for orientation on which side of the statutory threshold a water sits. The waters shown as below the threshold do not appear on the NHDES list of waterbodies over 1,000 acres published with the seasonal dock notification form. Confirm anything that matters with NHDES.
What the Rules and the Galvanizers Say About Dock Hardware
Fasteners and connectors are the smallest line on a dock and the one most often left to whatever the store had. These are the published positions this site relies on when it talks about them. The first three are New Hampshire rules; the rest come from the hot-dip galvanizing industry’s own trade association and from NHDES lake monitoring, and they are labelled as such.
The New Hampshire rules that touch hardware work
- A seasonal docking structure must be removed from the water before any paint, stain or other preservative coating is applied, and not returned to the water until the coating is dry (Env-Wt 513.22(b)(4)).
- Changing only construction materials on an existing legal dock needs no wetlands permit only if the size, location and configuration are unchanged, no work is done on any portion of the structure below the water surface at the time of repair, and no work is tidal (NHDES Docks in Non-Tidal Areas FAQs; see Repair in Kind above).
- Where a repair does need authorisation, the in-kind repair or replacement of an existing legal docking structure is classified as a minimum impact project (Env-Wt 513.25). Repair of a duly registered non-tidal dock is listed among the statutory exemptions (Env-Wt 308.02(j)).
Treated lumber and fasteners
The American Galvanizers Association states that wood preservative formulations were revised in 2003, that the change increased the corrosivity of the wood when in contact with metal parts, and that the two most popular treatments — alkaline copper quaternary (ACQ) and copper azole (CA) — are both active corrosion materials. Its position is that only two corrosion protection systems are recommended with them: hot-dip galvanized steel and stainless steel, because hot-dip galvanizing provides a thicker layer of zinc than other zinc-coated fasteners. Connector plates, joist hangers, bracing plates and fasteners of all types should be one or the other. The ASTM specification for hot-dip zinc coating on hardware is ASTM A153.
Zinc in fresh water, and New Hampshire’s water
The AGA states that corrosion of zinc in fresh water is controlled largely by impurities in the water, that relatively small differences in water content or conditions can produce substantial changes in corrosion rate, and that there is no simple rule governing the corrosion rate of zinc in fresh water. The one trend it says the data support is that hard water is much less corrosive than soft water, because moderate or high hardness lets a protective scale of calcium carbonate and basic zinc carbonate form on the galvanized surface. It also states that hot-dip galvanized coatings show no significant difference in corrosion rate at temperatures below −40 °F.
On New Hampshire’s side of that equation: in its 2017–2019 probability survey of 50 randomly selected lakes, NHDES found that only 19.6% of the state’s lakes met its expected acid neutralizing capacity (buffering) of at least 20 mg/L, and 80.4% fell below it. Its trend analysis of 150 lakes found specific conductance rising significantly in 41% of them from 1991 to 2018, which NHDES links in part to road salt.
A caution we hold ourselves to: acid neutralizing capacity is a measure of buffering, not of hardness, and the NHDES summary does not publish a statewide hardness figure. We cite it as evidence that New Hampshire lake water is poorly buffered, not as a hardness reading for any particular lake.
Galvanized steel in contact with other metals
The AGA reproduces a table (British Standards Institution PD 6484:1979, Table 23) rating the additional corrosion galvanized steel suffers when in contact with another metal. For immersion in fresh water:
| Metal in contact with galvanized steel | Fresh water, immersed |
|---|---|
| Stainless steel (austenitic, ~18% chromium) | 0–2 |
| Aluminium and aluminium alloys | 1 |
| Copper | 1–2 |
| Carbon and low-alloy steel | 1–2 |
Key: 0 — no or only very slight additional corrosion, usually tolerable; 1 — slight or moderate additional corrosion, which may be tolerable in some circumstances; 2 — fairly severe additional corrosion, protective measures usually necessary; 3 — severe, contact should be avoided. The AGA adds that under very humid conditions galvanized surfaces may require electrical isolation from aluminium or stainless steel, and that with copper or brass in a moist environment rapid corrosion of the zinc may occur — even runoff from copper surfaces can carry enough dissolved copper to cause it.
Rules per Env-Wt 513.22 and 513.25 and Env-Wt 308.02, retrieved 8 October 2026. Industry positions and Figure 15 per the American Galvanizers Association, Performance of Hot-Dip Galvanized Steel Products, retrieved 8 October 2026 — a trade body for the galvanizing industry, cited for its own published positions. Lake figures per NHDES, Summary of New Hampshire’s Lakes, Ponds and Reservoirs, retrieved 8 October 2026.
Where This Comes From
Everything above is drawn from published New Hampshire statute and NHDES material. The primary references are:
- NHDES — Docking Structures and Shoreline Stabilization
- NHDES — Docks in Non-Tidal Areas FAQs
- RSA 482-A:3 — Excavating and Dredging Permit; Certain Exemptions
- NHDES WB-28 — Voluntary Non-Tidal Dock Registration
Rules change, and summaries age. If you are relying on anything here for a decision, check it against the current NHDES material or ask us to check it with you. We would rather spend twenty minutes on that than have you order a dock you cannot install.