Landscaping, Drainage & Hardscaping in Montgomery County, Maryland

Drainage and Stormwater Services in Montgomery County

Montgomery County's residential core was built primarily in the 1950s — a decade when the county's population grew 107%, from 164,402 to 340,928 residents. That growth era matters for drainage today: the grading, drainage channels, and stormwater infrastructure designed for a 1960s Silver Spring or Wheaton lot were not engineered for today's stormwater volumes. Decades of successive landscaping projects have altered grades, filled original drainage channels, and left downspout runs too short to clear foundations.

The entire county lies in the Maryland Piedmont region — a geographic zone characterized by clay-heavy, low-permeability soils that shed water rather than absorb it. Clay soil cannot move water downward fast enough during a DMV thunderstorm regardless of surface slope. The result is pooling on lawn that looks flat, turf that stays saturated for days, and water that finds the path of least resistance — which is frequently a foundation wall.

Actaeon installs French drain systems, surface drainage inlets, buried downspout extension networks, and graded swales designed to move water away from structures. For yard drainage problems rooted in permanent grade deficiencies — where water pools because of how the lot was originally shaped — we regrade and install subsurface drainage to handle what the grade alone cannot move. Where projects qualify, we design installations to be compatible with the Montgomery County RainScapes Rebate (see below).

For commercial and government projects, Actaeon provides BMP installation and maintenance for stormwater facilities, including underground infrastructure requiring county-certified contractors. Montgomery County Code Section 8-29B requires water runoff to be managed for construction of new single-family dwellings and additions to existing single-family dwellings on lots under 15,000 square feet — a regulation that affects many infill and addition projects in older county neighborhoods.

Retaining Walls, Patios, and Hardscaping

Montgomery County's most topographically varied residential neighborhoods — Potomac, Bethesda, Chevy Chase, and the hills above the DC line — have properties where retaining walls are load-bearing structural elements, not decorative features. Retaining walls on sloped lots handle real lateral pressure from saturated clay soils uphill. Undersized or deteriorating walls on these properties can fail suddenly, and failures on sloped Montgomery County lots typically involve hillside movement, not cosmetic damage alone. We size and design walls to handle calculated soil loads.

Patio construction on sloped or near-flat lots requires base preparation that homeowners often underestimate: setting grades to drain away from the structure, managing runoff off the patio perimeter, and ensuring base compaction holds under clay soils that shift with freeze-thaw cycles. A patio pitched toward the foundation, or one that pools water at its edge, can create the drainage problem it was supposed to solve.

Driveways, walkways and stone installations, and concrete and masonry work is common across the county's older neighborhoods, where original concrete has settled, heaved, or cracked due to clay soil movement. In Rockville, driveways and patios over certain size thresholds require City of Rockville permits — permit requirements that don't apply in unincorporated Bethesda or Potomac, where MCDPS handles permitting instead.

Sod Installation and Landscaping

Sod installation across Montgomery County follows soil preparation calibrated to Piedmont clay: amendment and grade correction before sod is laid, because sod installed directly on compacted clay without amendment fails quickly. We install and establish sod for residential lawns, HOA common areas, and restoration projects where erosion control requires immediate ground cover.

Landscaping services include native plant installation — relevant both to RainScapes project eligibility (conservation landscapes must be at least 75% native plants to qualify for the rebate) and to long-term establishment success on Piedmont clay soils, where plants appropriate to the Maryland Piedmont region significantly outperform ornamentals not adapted to the local hydrology.

The Montgomery County RainScapes Rewards Rebate

Montgomery County operates the RainScapes Rewards Rebate program — one of the largest residential stormwater incentive programs in the DMV. Residential property owners can receive rebates up to a $7,500 lifetime maximum per property for qualifying on-site stormwater practices. Commercial, HOA, and institutional properties are eligible for up to a $20,000 lifetime maximum per property. The cap is per property — not per project.

Qualifying practice types:

• Rain gardens — engineered planted depressions that capture and infiltrate runoff
• Conservation landscapes — minimum 250 square feet, minimum 75% Maryland native plants
• Water harvesting — cisterns and rain barrels (rain barrels sub-capped at $250)
• Green roofs
• Permeable pavement retrofits
• Pavement removal

Rebate applications must be submitted and approved before installation begins. After completing the installation, property owners submit documentation for reimbursement. The rebate does not cover standard drainage infrastructure — only the specific green infrastructure practices listed above. Actaeon designs and installs qualifying RainScapes practices and can walk you through the application process.

Permitting in Montgomery County

Most of Montgomery County is unincorporated, with permitting handled by the Montgomery County Department of Permitting Services (MCDPS): 2425 Reedie Drive, 7th floor, Wheaton, MD 20902 · 240-777-0311 · Monday–Friday 7:30 a.m.–4 p.m. MCDPS covers all unincorporated communities including Bethesda, North Bethesda, Potomac, Chevy Chase, Silver Spring, Wheaton, Aspen Hill, Germantown, Kensington, Olney, White Oak, and Colesville.

Three incorporated cities issue their own permits — MCDPS does not cover them:

Rockville — Permits through the City of Rockville Inspection Services Division ([email protected] · 240-314-8240). Driveways, patios, grading disturbances, and drainage modifications that affect existing patterns require city permits. Retaining wall thresholds are published at rockvillemd.gov.

Gaithersburg — Site permits are required for retaining walls, fences, driveways, patios, grading, sediment control, forest conservation, and stormwater management. Permits through Gaithersburg Permitting & Inspections at gaithersburgmd.gov.

Takoma Park — The City of Takoma Park issues its own permits, separate from MCDPS. Contact the city directly at takomaparkmd.gov for current thresholds.

If your property address is in Rockville, Gaithersburg, or Takoma Park city limits, your permit goes to the city — not to MCDPS — regardless of how you think of your location. Actaeon manages permit applications for every qualifying project.

Watersheds and Local Environment

Montgomery County drains to four major watershed systems, each with distinct regulatory implications for land development and drainage projects:

Potomac River — drains north and west Montgomery County.

Rock Creek — drains central and southern Montgomery County.

Patuxent River (Primary Management Area) — approximately 61 square miles of Montgomery County drain into the Patuxent headwaters and WSSC reservoirs. The Patuxent Primary Management Area (PMA) imposes additional buffer and development restrictions on top of standard MCDPS permitting, designed to protect reservoir water quality. Projects near stream corridors in eastern Montgomery County may face MDE requirements beyond county permit scope.

Ten Mile Creek — drains northwest Montgomery County, primarily the Clarksburg area. Designated a Special Protection Area (SPA), with development restrictions that go beyond standard county stormwater requirements.

The entire county lies in the Maryland Piedmont region, which shapes both plant selection and drainage behavior. Piedmont clay soils — the dominant soil type across developed Montgomery County — retain water rather than absorb it, which is the root physical cause of most drainage problems Actaeon resolves in the county.

Communities We Serve in Montgomery County

Actaeon serves homeowners and businesses throughout Montgomery County, including Bethesda, North Bethesda, Chevy Chase, Potomac, Rockville, Silver Spring, Gaithersburg, Germantown, Kensington, Olney, Wheaton, Takoma Park, Aspen Hill, White Oak, Colesville, Laytonsville, Sandy Spring, Damascus, Darnestown, and North Potomac — and surrounding unincorporated areas across the county.

Frequently Asked Questions