Occasionally homeowners have questions about drainage issues between properties. Minor changes in drainage patterns such as modifying the discharge from a downspout, installing a raised planter, planting or removing vegetation, or contouring land areas less than 2,500 square feet usually don’t require a plan or building permit.
General drainage guidelines:
- Roof and surface drainage collected by a system or pipe should be discharged approximately 10 feet from the edge of the property to allow some natural spreading of the water. Concentrated flow shouldn’t be discharged at a neighbor’s property line, or onto the sidewalk, street, curb or gutter. If the slope is toward neighboring properties, drainage should be released so that it will flow away from downslope structures to the maximum practical extent. Don’t tie several downspouts together creating concentrated flow in one pipe, but allow for sheet flow through grass or mulch to absorb and divert flow. Additional water retention strategies can be used to reduce downslope impacts, such as French drains, soil amendments, rain gardens or similar features.
- Property owners shouldn’t build systems or structures that result in standing water on a neighbor’s property. Fences and retaining walls shouldn’t concentrate runoff as to cause a negative drainage impact.
- As of July 2014, new sump pumps that are installed must connect to the storm sewer or be released at least 10 feet from the edge of the property. Sump pumps must not discharge to the sidewalk, street, stormwater planters, pervious driveways or to the gutter. Sump pump discharge must not result in concentrated flow to off-site owner’s property. Read more about the sump pump discharge policy.
- The fill around existing structures should be properly compacted and graded to slope away from the house, with the objective of achieving at least a 5 percent slope for a minimum of 10 feet (making the ground 6 inches lower than the ground surface at the house wall). This may not always be feasible, depending on the existing grading and characteristics of the existing structure, side yards, and vegetation. As much effort should be made as feasible to ensure positive drainage away from a structure’s foundation. If necessary, a shallow swale, or drainage path, can be graded to help carry runoff away from the building foundation or from low areas in the yard where the soil has settled.
Drainage disputes between private property owners are private matters that must be handled directly between the affected property owners. We have no authority to direct corrective measures or resolve the issues. If you have questions about projects under construction or recently completed projects, contact Tom Artley at 703-228-3693.
For more information about drainage problems and how to address them, review the guidebook You and Your Land: A Homeowner’s Guide for the Potomac River Watershed, published by the Northern Virginia Soil and Water Conservation District. It’s a useful resource for the economical care and maintenance of your property.