The Problem: Managing Water Around a Walnut Creek Home

Water around and beneath a home can come from several sources. Rainwater can soak into the surrounding soil and move below the surface, while roof runoff can introduce significant amounts of additional water if downspouts don’t carry it to an appropriate discharge point.

At this Walnut Creek property, Ward Construction designed a drainage system extending along the left, rear and right sides of the home, excluding the garage. The goal was to collect both subsurface water and water coming from the home’s roof downspouts and provide a controlled way to move that water away from the property.

Because gravity drainage alone wasn’t sufficient to carry the collected water all the way to its final discharge point, the system incorporated a sump and pump.

The Solution: A Perimeter Drainage System

Ward Construction constructed a rock-filled drainage trench around three sides of the house.

The system included two separate drainpipes. A perforated pipe was installed to collect subsurface water from the soil surrounding the home. A second, non-perforated pipe was designed to collect and carry water from the roof downspouts.

Keeping these functions separate allows groundwater and roof runoff to be collected efficiently while ultimately directing both toward the drainage system’s discharge point.

The perforated drainpipe was installed below the grade of the soil beneath the house and pitched toward the point of discharge. It was placed on a gravel bed with the perforations facing downward and then surrounded by drain rock. The trench was constructed at least 12 inches wide, providing a substantial layer of rock around the four-inch perforated pipe.

A clean-out was also installed at the upper end of the perforated line so the drainage pipe could be tested or cleaned when necessary.

Using a Sump Pump to Move Water Away From the Home

One of the important features of this project was the sump pump system.

Rather than relying entirely on gravity, the new perimeter drains discharged into a sump. From there, the collected water could be pumped toward the street.

Ward Construction routed the discharge line beneath the sidewalk and through the curb so that the water could empty into the street gutter. Concrete along the path of the new drain was removed and replaced as necessary during installation.

A sump pump can be an important part of a residential drainage system when site elevations don’t provide enough natural fall to move water from the collection area to an appropriate discharge point.

Addressing Both Groundwater and Roof Runoff

An effective drainage solution often needs to consider more than one source of water.

For this Walnut Creek home, the perforated portion of the system was designed to intercept subsurface water, while the solid pipe handled roof runoff from the downspouts. Both ultimately directed water toward the sump and away from the home.

This approach helps manage water before it can remain concentrated in the soil immediately around or beneath the house.

Additional Sub-Area Repairs

During the project, Ward Construction also addressed rusted jacks in the home’s sub-area, removing and replacing them as needed.

While this work was included with the drainage project, the proposal doesn’t identify the cause of the rusting, so it would be inaccurate to assume that drainage or moisture conditions caused their deterioration.