Environmental Rules in Gaithersburg, MD

If you live in Gaithersburg or are thinking about moving there, environmental rules are one of those things you probably won't think about until they affect you directly. Gaithersburg has 4 specific rules on the books covering different aspects of environmental rules, and some of them might surprise you.

Stormwater Management

Gaithersburg requires city-approved stormwater management for nearly all new development and redevelopment inside city limits under City Code Chapter 8, Article III. Projects disturbing more than 5,000 square feet must control runoff using environmental site design, and the city, not Montgomery County, reviews and permits the plans.

Key details: Exemption threshold: 5,000 sq ft land disturbance. Redevelopment standard: 50% impervious area reduction/treatment. Performance bond: Not less than construction cost. Liability insurance: $2,000,000 minimum. Advance notice: 48 hours before starting work.

A stormwater violation is a municipal infraction enforceable under § 1-9, with the penalty for each initial and repeat offense set by city council resolution (§ 8-31). The city may also seek injunctive relief, mandamus, or other court orders to force compliance, and may sue in civil court for damages when a developer fails to install or maintain approved controls, recovering its attorney, consultant, and witness fees in that action (§ 8-31).

Flood Zones

Gaithersburg bars any grading, filling, new construction, substantial improvement, or watercourse alteration inside a mapped special flood hazard area until a site development permit is issued under Chapter 10. The city's own floodplain administrator, not Montgomery County, reviews every application against the 2006 flood insurance study and FIRM panels for the city.

Key details: Permit required: Site development permit before any SFHA work. Enforcing official: City floodplain administrator (city manager designee). Base flood data: County FIS dated September 29, 2006 + FIRM. Permit validity: 180 days, extendable 90 days at a time. Penalty: Municipal infraction; each day a separate offense.

Failing to obtain a site development permit before building in a flood hazard area is itself a violation of Section 10-52 and is enforced as a municipal infraction under Section 10-54, with a fine set by city council resolution for the initial violation and each subsequent day the violation continues counted as a separate offense. Before any fine, the floodplain administrator issues a written notice of violation or stop work order under Section 10-53 listing the sections violated, ordering remedial action, and advising the property owner of the right to appeal to the board of appeals.

Erosion Control

Gaithersburg requires grading permits for land-disturbing activities and enforces drainage standards to protect adjacent properties and waterways. Grading must maintain positive drainage away from structures and must not redirect stormwater onto neighboring properties. Montgomery County reviews grading plans in coordination with the city for projects meeting disturbance thresholds.

Key details: Grading Permit: Required for drainage changes. Foundation Slope: 6 inches in first 10 feet. Retaining Wall Permit: Over 4 feet height. Public Works: (301) 258-6370. Building Division: (301) 258-6330.

Grading without a permit when required is subject to stop-work orders and fines. Redirecting stormwater onto neighboring properties triggers enforcement action and required remediation. Grading in stream buffers or forest conservation areas without approval carries penalties up to $10,000 per day under Montgomery County regulations.

This is one of the stricter rules in Gaithersburg's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

Flood Elevation Requirements

New and substantially improved homes in a Gaithersburg special flood hazard area must have their lowest floor at least one foot above the base flood elevation shown on the city's FIRM. Nonresidential buildings that floodproof instead must reach two feet above BFE, the city's defined 'flood protection elevation.'

Key details: Residential minimum: 1 foot above base flood elevation. Nonresidential floodproofing minimum: BFE plus 2 feet freeboard. Zone AO minimum: Depth number plus 2 ft, or 4 ft minimum. Verification required: Elevation certificate at lowest-floor stage and at C.O.. Flood opening ratio: 1 sq in per sq ft of enclosed area.

Building below the required freeboard elevation is treated the same as building without a permit: it is a Section 10-52 compliance failure subject to a Section 10-54 municipal infraction fine set by city council resolution, with each day of noncompliance a separate offense. The floodplain administrator can also refuse to issue the elevation certificate and certificate of occupancy until the lowest floor is corrected to meet Section 10-34's one-foot standard.

The Bottom Line

Gaithersburg's environmental rules rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Gaithersburg is broadly strict or permissive.

These rules come from Gaithersburg's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.