Is a dam under 25 feet exempt from permitting in North Carolina?

Not automatically. G.S. 143-215.25A(a)(6) exempts dams under 25 feet in height or under 50 acre-feet capacity unless the Department determines that failure could result in loss of human life or significant damage to property below the dam. Where an occupied structure is downstream, that determination is normally made and the exemption is unavailable.

Can an engineer exempt a small dam in North Carolina?

Subdivision (8) of G.S. 143-215.25A allows exemption for a dam less than 20 feet high or under 15 acre-feet where a qualified engineer with demonstrated dam design experience conducts dam failure analyses and determines the dam is not a high hazard dam. The size threshold only opens the route; the engineering finding decides it.

Does a farm pond dam need a permit in North Carolina?

It depends on downstream consequence, not on the pond being small or private. Recreation ponds do not qualify for the agricultural exemption, and the single-ownership exemption fails if the dam threatens human life or property below it. A pond dam with an occupied dwelling downstream is normally jurisdictional.

Dam safety worked examples

Does This 18-ft Farm Pond Dam Need a Permit?

By Michael Flynn, PE · water resources & dam safety engineer

The most common belief about North Carolina dam regulation is that small dams are exempt. The statute does contain size thresholds — and every one of them is conditional. This walks G.S. 143-215.25A subdivision by subdivision for a specific pond dam, which is the only way the answer ever actually comes out.

The dam

Height	18 ft
Impoundment capacity	22 acre-ft
Purpose	Recreation / fishing pond
Ownership	Single private owner
Construction	Built 1971, no federal agency involvement
Downstream	One occupied dwelling ~2,400 ft below, on land the owner does not own

Step 1 · Federal exemptions

Subdivisions (1) through (4) — not applicable

Sub	Exemption	Applies?
(1)	USACE / TVA / other federal agency designed or approved and supervised construction	No
(2)	NRCS financial assistance, NRCS designed or approved and supervised	No
(3)	FERC licensed or application pending	No
(4)	Used with NRC-regulated electric generating facilities	No

Check (1) and (2) harder than they look. Both require the agency to have done two things — designed or approved the plans and supervised construction. And under subsection (b) the exemption ends once the supervising federal agency hands operation and maintenance to a local entity. A great many NRCS watershed dams have been turned over to local sponsors, and those dams are regulated even though everyone involved still calls them "the NRCS dam."

Step 2 · The single-ownership exemption

Subdivision (5) — fails on the dwelling

(5) exempts a dam "under a single private ownership that provides protection only to land or other property under the same ownership and that does not pose a threat to human life or property below the dam."

Single private ownership? Yes
Protects only the owner's property? Yes
Poses no threat to life or property below? No — occupied dwelling downstream

→ Exemption (5) not available

Step 3 · The size exemption everyone quotes

Subdivision (6) — conditional, and the condition bites

(6) exempts a dam "that is less than 25 feet in height or that has an impoundment capacity of less than 50 acre-feet, unless the Department determines that failure of the dam could result in loss of human life or significant damage to property below the dam."

Height 18 ft < 25 ft → threshold met
Capacity 22 ac-ft < 50 ac-ft → threshold met (either one suffices)

But: could failure result in loss of human life or significant property damage?
Breach model gives Q_p ≈ 7,150 cfs reaching an occupied dwelling in minutes.

→ Department determination expected: yes, it could
→ Exemption (6) not available

"Under 25 feet so it's exempt" is the single most expensive misreading of this statute. The size thresholds open a door; the consequence finding closes it. An owner who relies on height alone, skips the permit, and is later found jurisdictional does not merely owe a filing — they own an unpermitted high-hazard dam with no EAP and no approved plans.

Step 4 · The agricultural route

Subdivision (7) — wrong purpose here

(7) covers dams "constructed for and maintain[ing] the purpose of providing water for agricultural use," where a licensed PE or a qualified NRCS / county / Soil and Water district person with federal job approval authority under Chapter 89C designed or approved the plans, supervised construction, and registered the dam with DEMLR before construction. It expressly does not apply to dams determined to be high hazard.

Purpose is recreation, not agricultural water supply → not available
(Registration before construction would also fail — built 1971, unregistered)

Step 5 · The engineered exemption

Subdivision (8) — available on size, decided by analysis

(8) exempts a dam "less than 20 feet in height or that has an impoundment capacity of less than 15 acre-feet" where "a qualified engineer who demonstrates to the satisfaction of the Department experience in dam design conducts dam failure analyses and determines that the dam is not a high hazard dam."

Height 18 ft < 20 ft → size gate passed
(Capacity 22 ac-ft > 15 ac-ft, but the statute reads "or")

Required: qualified engineer performs dam failure analyses
Required finding: dam is not high hazard

From the flood rise test:
rise at the dwelling = 1.2 ft ≤ 1.5 ft, outside the direct path
→ not Class C → finding supports the exemption

This is the only exemption route still open, and it is an engineering determination, not a measurement. The dam is under 20 feet, so it passes the size gate; whether the exemption is actually available depends entirely on whether a qualified engineer's failure analysis supports a not-high-hazard finding. At 1.2 ft of rise it does. At 1.7 ft it does not, and the dam is jurisdictional.

Step 6 · Check your source is current

Subdivision (8) is missing from NCDEQ's own handout

The NCDEQ hazard classification criteria form reproduces G.S. 143-215.25A as of 06/29/17 and shows only subdivisions (1) through (7). The current statute — history running 1993 c. 394 s. 3, S.L. 2009-390, 2011-394, 2012-143, 2013-265 and 2021-180 s. 12.21 — includes the (8) route relied on above. If you work the exemption tree from the agency handout, you will conclude this dam has no path to exemption at all.

Verify exemptions against ncleg.gov, not against a PDF. Agency handouts, consultant templates and secondary summaries all go stale, and dam safety statutes get amended more often than people expect. The statute text is the only thing that binds.

Tools used

NC Permits & Exemptions →

All eight categories in one table

Dam Breach Peak Discharge

The failure analysis (8) requires

Hazard Classification

The not-high-hazard finding

The rest of this series

These four examples follow one structure through the whole decision chain, because in practice that is how the questions actually arrive:

Breach parameters for a 22-ft earthfill dam — produces the failure hydrograph everything else depends on.
Class B or Class C? The 1.5-foot flood rise test — turns that hydrograph into a hazard classification.
Does an 18-ft farm pond dam need a permit? — the classification decides whether the size exemption survives.
Spillway design flood for a Class C dam — and the classification sets the storm the spillway must pass.

Scope. This page is general information about North Carolina dam safety regulation, current as of 2026-08-28. It is not an engineering opinion about any specific structure and it is not legal advice. Requirements change when the General Assembly amends the Dam Safety Law or the Environmental Management Commission amends the rules — always confirm against the current text of the statute and 15A NCAC 02K, and contact the NCDEQ Dam Safety Program for a determination that binds.