Sediment, Erosion & Construction


Erosion is the process of soil and rock being transported and deposited to other locations by water flow and/or wind. It is a natural process, and erosion helped shape the landscape of our County.

Erosion shifts from being a natural process to problematic when human activities, such as construction projects, cause large amounts of erosion and sediment deposition in our streams.


Image of a clump of sedimentExcess sediment (beyond natural erosion) can be a pollutant


Sediment and Erosion Issues

Problems caused by excessive sediment in streams include:

  • Unsightly waterways
  • ​Loss of important topsoil
  • Stream bank instability
  • Smothering of the spaces between rocks where fish lay their eggs
  • Cloudy water, which prevents fish from seeing their food
  • Abrasion of fish and other stream life
  • Reduced flow-carrying capacity in the stream channel due to sediment settling (which increases the potential for flooding)
  • Diminished water quality
  • Other pollutants carried by or attached to the sediment (such as phosphorus and petrochemicals) 


Image of a frog in sediment Sediment smothers living organisms and abrades or coats their skin. 


Stream Bank Erosion

If you spot a stream bank with active erosion or collapse, and sediment is discharging into the stream, report it to 311 . DEP investigates complaints and will refer the problem to the relevant partner agency.

Common complaints include:

  • Severe stream bank erosion on property. Often mowing, herbicide use, and tree removal up to the stream's edge make banks more vulnerable to erosion because of the absence of roots, which bind soil in place.

  • Erosion of stream channels, which exposes sanitary sewer infrastructure.

  • Stream channel erosion resulting from a water main or sewer main rupture. (Cases are referred to the Washington Suburban Sanitary Commission )

  • Stream erosion that is causing damage to a public road. (Cases are referred to the Montgomery County Department of Transportation )


Image of an exposed sewer pipe.

Stream erosion can expose utility mains.

Image of a house at risk from stream bank erosion.

At this home, the yard is caving into the stream.
This type of problem is often caused by a lack of vegetation along the stream banks.


Filing a Sediment or Erosion Complaint

Public Right-of-Ways 

If the erosion problem occurs in the public right-of-way or as part of the public storm drain system, please report the issue to MC311.


Private Property Erosion

Please note that if the erosion problem is on private property, the only assistance that DEP provides is some technical assistance on how owners can solve the problem themselves.

For guidance on an erosion problem, submit a request to DEP:

DEP also does not deal with erosion gullies and dry channels. Erosion gullies and dry channels are normally the responsibility of the property owner, except when they are part of the public storm drain system, then refer to the public right-of-ways section above.

Indicate that you are interested in filing an erosion control complaint. It's helpful to provide as much of the following information as possible:

  • Your contact information, for follow-up contact
  • The location of the complaint with street address if possible
  • The frequency and full extent of the problem
  • Pictures or video 



Lot-to-Lot Drainage

There are no specific Codes regarding nuisance drainage or discharge of water specifically. In virtually all cases where there is no ongoing construction, this is a civil matter AND Montgomery County DOES NOT have the authority to take enforcement action. In extremely rare cases, enforcement action may be taken if the following criteria are met. If the water discharge creates a condition that would or could result in "SUBSTANTIAL DAMAGE" to another property. "SUBSTANTIAL DAMAGE" means damage sustained by a structure or property if the cost of restoring the structure or property to its previous condition is at least 50% of the market value of the structure or property before the damage occurred.

If the water runoff is occurring as a result of construction, you may submit a complaint to the Department of Permitting Services. To file a complaint that meets the above referenced criteria not related to construction or re-grading, the DHCA Housing Code Enforcement unit handles enforcement of this issue but does not have jurisdiction inside the municipalities of Gaithersburg and Rockville. Complaints regarding rental properties within the City of Takoma Park are also handled by DHCA but complaints regarding commercial or owner occupied properties are handled by the City of Takoma Park. Water runoff complaints must be made in writing and sent to DHCA Housing Code Enforcement at 1401 Rockville Pike, 4th Floor, Rockville, MD 20852. Please include the address of the property causing the water problem, length of time problem has been occurring and any other pertinent details relating to the estimated costs of restoring the structure damage.  

  • Learn more.
  • Call 311 (240-777-0311 from outside of the County; 7-1-1 for Maryland T-T-Y Relay)

Indicate that you are interested in filing an erosion control complaint. It's helpful to provide as much of the following information as possible:

  • Your contact information, for follow-up contact
  • The location of the complaint with street address if possible
  • The frequency and full extent of the problem
  • Pictures or video 


Construction Runoff

If you spot a construction site or any other land-disturbing activity that requires a permit (greater than 5,000 square feet) with discolored or muddy water running off it, you should report it:


Aerial image of a construction site.

A permitted construction/land-disturbance site must have a sediment control plan as part of its permit.


Here are some examples of sediment violations and problems you can report:

  • An abandoned construction site where sediment control measures, such as plastic silt fences, are frayed or worm out and not functioning as intended. These devices might need to be replaced to prevent sediment erosion and runoff.
  • Streams adjacent to construction sites or land-disturbing activities with excessive siltation where you can see a direct flow connection to the construction site.
  • Sediment control practices (such as silt fences) that have been breached because of excess water or sediment build-up.
  • Other failing, inadequate, or improperly maintained sediment control best management practices on a site that is permitted for construction or land disturbance. 

​Construction/land disturbance sites less than 5,000 square feet are not required to have a sediment and erosion plan and, therefore, don't fall under the Department of Permitting Services jurisdiction.


Image of a silt fence protection. A permitted site should have adequate, functioning sediment control measures (such as silt fences) in place.

Image of gravel at the entrance to a construction site. One common sediment control measure is a gravel entryway, which prevents trucks from tracking sediment from the disturbed site onto the road.

Image of a sediment pond Another sediment control measure is a pond into which the site drains so that sediment can settle before water is allowed to discharge into nearby creeks.

Image of sediment flowing off a construction site.

This sediment problem occurred during a rainstorm, when the sediment ran off the site and entered the storm drain system.


Image of a sediment flowing into a storm drain. The storm drain system flows directly into local creeks.