Why does my yard flood when it rains?

A yard floods when more water arrives than the ground can soak up or carry away. Usually that comes down to one of four things: the shape of the land, the soil, where the runoff is coming from, or water rising from below. A yard that is wet even in dry weather points to a fifth cause, a leak. Telling them apart matters, because each has a different fix and some fixes make the others worse.

First, is it really a problem?

The Northern Virginia Soil and Water Conservation District considers a yard that dries out within a day or two after a rainstorm normal, and a yard with a wetness problem one whose puddles or soggy areas last for several days after storms or never go away.^[1] Note how long the water stays after a few storms before you call anyone. It is the single most useful thing you can tell a contractor.

In the district's words, wet areas that persist for several days are "commonly caused by improper grading (low spots or depressions) or poor infiltration of water into the soil."^[1]

The ground is shaped wrong

Water runs downhill and stops in the low spots. Areas around the foundation should slope away from the walls, and the swales between neighboring houses should be graded so runoff does not stagnate on your property.^[1] The district's guideline is at least a 5% grade for ten feet around the house, a drop of at least six inches; a negative grade, tilting toward the house, is the condition to fix.^[4]

Grades change over time. Soil can settle along foundations, raised beds and edging can act as dams, and a patio or shed can block a path the water used to take.

Some low spots have a cause underground. The district's list includes buried brush, stumps or debris from past construction that rots and leaves a void, and large rocks buried in the yard fill that kept the soil around them from compacting.^[5]

The soil cannot soak it in

Even a well-graded yard floods if the water cannot get into the ground. Poor infiltration can be caused by compacted soil, soil with high clay content or a shallow depth to bedrock, and water can perch on top of these materials at the surface or just below it.^[1]

Compacted soil soaks up less, so a lawn that takes a downspout's water needs care. Extension suggests aerating a lawn every three years where an extension pipe sends runoff onto it, to keep the water soaking in.^[7]

Too much water arrives in one place

Hard surfaces send their water somewhere. Runoff problems are made worse by impervious surfaces such as roofs, roads and driveways, which keep water from soaking in.^[4] A roof can dump a large volume of water at a few downspouts in a heavy storm, and a driveway or a neighbor's yard uphill can add more.

Near the house, the district lists gutters that need cleaning or are undersized, downspouts and sump pump pipes, and poor grading around foundation walls as possible causes of wetness near the house.^[2] Watch your downspouts in a storm: if water pours out right beside the wall or onto the soggy area, start there. Our guide to extending a downspout away from the foundation covers the simplest fix.

Fences are a surprising culprit. An improperly installed fence can block overland storm flow across property lines and make water pond in your yard or your neighbor's.^[6] Fairfax County's flood program says water must be able to flow under and through a fence, and the bottom of a fence crossing a swale should sit at least six inches above the bottom of the swale.^[6]

Water is coming up from below

Some wet ground has little to do with rain. High groundwater is generally found in low parts of the landscape, especially floodplains next to perennial streams, and seepage can come from natural springs on slopes.^[1] Groundwater is closest to the surface in colder months,^[1] so a yard that is soggy all winter and dry in August may be telling you this.

A large area that stays wet for months may be more than a drainage problem. Disturbing a jurisdictional wetland in Virginia is prohibited without a permit from the Army Corps of Engineers Norfolk Office or the Virginia Department of Environmental Quality.^[4] Ask your locality or soil and water district before anyone fills or drains it.

It is wet even when it is dry

If one spot never dries out, suspect a leak. Leaky water pipes, lawn sprinkler systems, outdoor faucets, ponds, pools and fountains can keep a yard wet all the time, and the district warns that the actual source of the wetness may not be at the same place where you see wetness on the surface.^[1] A water bill that has crept up is a clue. Call your water utility or a licensed plumber before you pay for drainage work.

What fixes look like

Each cause has its own family of fixes: regrading and filling low spots, loosening and amending compacted soil, moving roof water away from the house, open swales and rain gardens for surface runoff, and buried systems such as French drains for soggy ground with somewhere lower to send the water. Whatever the fix, the water has to go somewhere. "Whenever you are redirecting runoff, you must send it to a suitable outlet."^[3] Redirecting runoff without soaking it into the soil can harm neighboring properties.^[3]

When to call a licensed pro

Call a pro when water reaches the foundation or the basement, when the wet area is large or keeps growing, when the fix means moving soil with a machine or burying pipe, or when you cannot tell where the water is coming from. Regrading and trenching are excavation: Virginia 811 asks for a locate request at least 3 working days before any digging, and on a hired job your contractor is responsible for contacting Virginia 811.^[8]

Virginia's Board for Contractors places excavation, clearing and grading of land under the landscape service contracting specialty, and the home improvement contractor specialty also covers that work.^[9] Check any contractor's licence on DPOR's License Lookup.^[10] To decide between a landscaper and a drainage contractor, read who to call for a wet yard, and for prices see what a French drain costs in Virginia.

Browse drainage and French drain businesses, find excavation businesses in Blacksburg, or see more excavation answers.

Describe where the water collects and how long it stays, and licensed local contractors quote the fix.