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Smithtown, NY Environmental Rules: Erosion Control (2026)

Significant Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified August 2026

Key Facts

Governing law
Smithtown Code Ch. 153
Max disturbance at once
5 acres without approved SWPPP
Inspection frequency
Every 7 days, and after 0.5 inch of rain
Sediment trap cleanout trigger
50% of design capacity
Inspector notice required
48 hours before key construction stages
First-offense fine
Up to $350

Summary

Smithtown caps active soil disturbance at five acres at a time absent an approved plan, requires a qualified professional to inspect erosion and sediment controls every seven days plus after any half-inch storm, and orders sediment removed once traps are half full.

Construction phasing plan describing the intended sequence of construction activities, including clearing and grubbing, excavation and grading, utility and infrastructure installation and any other activity at the site that results in soil disturbance. Consistent with the Erosion Control Manual, not more than five acres shall be disturbed at any one time unless pursuant to an approved SWPPP. ... Sediment shall be removed from sediment traps or sediment ponds whenever their design capacity has been reduced by 50%. ... the applicant shall have a qualified professional conduct site inspections and document the effectiveness of all erosion and sediment control practices every seven days and within 24 hours of any storm event producing 0.5 inch of precipitation or more.

Full Breakdown

Chapter 153's erosion and sediment control component is built into the same SWPPP that clears a project for a permit. ' The plan must also detail dimensions, materials and installation specifics for every erosion and sediment control practice, including sizing of temporary sediment basins, plus a schedule for when each practice goes in and how long it stays (§ 153-8B(1)(h), (i), (k)). For projects that trigger the post-construction threshold (one acre or more, or discharge to an impaired water), a qualified professional such as a licensed engineer or landscape architect must inspect and document every erosion and sediment control practice's effectiveness at least every seven days, and again within 24 hours of any storm producing half an inch of rain or more, logging results in a site book available to the Stormwater Management Officer (§ 153-10A(2)).

Every applicant or developer must also have someone on site whenever construction or grading is underway to inspect and document control effectiveness (§ 153-10A(3)). Maintenance during construction requires sediment to be pulled from sediment traps or ponds once their design capacity has dropped by 50% (§ 153-10A(1)). The Town Engineering Department separately requires 48 hours' notice before starting construction, installing controls, or completing clearing and grading stages so its own inspectors can check the work (§ 153-12A(1)). Activities exempt from full SWPPP review, such as small-scale grading or fence and utility-pole installation, still must use erosion and sediment control measures scaled to the size of the work (§ 153-7B).

Violations & Fines

Falling short of these controls triggers a notice of inspection identifying the violation and required corrective action, and no further work beyond site stabilization may proceed until the Stormwater Management Officer signs off (§ 153-12A(2)). Chapter-wide penalties under § 153-14C apply: up to $350 for a first offense, $350 to $700 for a second within five years, and $700 to $1,000 for a third, each punishable by up to six months in jail, with every week of continuing violation treated as a new offense. The Town Attorney can sue to restrain the violation and recover the Town's investigation costs, and violators may be ordered to restore disturbed land to its original condition at their own expense.

Frequently Asked Questions

How much land can I clear at once under Smithtown's erosion rules?
Section 153-8B(1)(d) limits phasing to no more than five acres disturbed at any one time, consistent with the New York Erosion Control Manual, unless a specific approved stormwater pollution prevention plan authorizes more.
How often must erosion controls be inspected during construction?
Section 153-10A(2) requires a qualified professional, such as a licensed engineer or landscape architect, to inspect and document every erosion and sediment control practice at least every seven days, and again within 24 hours after any storm dropping half an inch of rain or more.
When do I have to clean out a sediment trap?
Section 153-10A(1) requires sediment to be removed from sediment traps or ponds as soon as their design capacity has been reduced by 50%, and the applicant or developer must maintain the facility properly at all times during construction.

Sources & Official References

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