Splash Blocks and Downspout Extensions

01

What a splash block does

A splash block spreads discharge and helps limit erosion at the downspout. It must face the correct direction and sit on a surface that continues away from the foundation.

02

Flexible and rigid extensions

Flexible extensions adapt around landscaping but can crush, sag or trap debris. Rigid extensions hold shape better but need appropriate support and placement. Hinged options can improve mowing access if returned to position.

03

How far should runoff be moved?

Distance alone is not the answer. The outlet should reach a location with positive drainage, adequate absorption or an approved connection, without creating a trip, erosion or property-line problem.

04

Maintenance and winter issues

Check for separation, mowing damage, sediment, nesting material and low points. Discharge across walks or driveways can create slippery or icy conditions when temperatures fall.

05

When buried drainage is considered

A buried system can remove visible extensions but needs suitable design, cleanouts and a reliable outlet. It should not be used to hide a downstream blockage or discharge problem.

Property assessment

Evaluate the final few feet of the drainage path

A splash block or extension receives concentrated runoff from a large roof area. Its direction, slope and condition determine whether that water disperses away or returns toward the wall. Inspect after mowing, storms and seasonal soil movement because small shifts can reverse the intended path.

Choose a component around actual use. Flexible pipe can route around landscaping but may crush or trap water. Rigid extensions hold shape but can interfere with walking or maintenance. Hinged sections work only when returned to the drainage position.

• Splash block is reversed or no longer level
• Extension ends in settled soil
• Flexible pipe is crushed or perforated
• Mowing repeatedly disconnects the lower section
• Runoff erodes mulch or soil at the outlet
• Discharge crosses a walk or freezes on pavement

Planning the work

Select a stable destination and maintainable route

The endpoint should have positive drainage, appropriate absorption or a designed connection. Secure joints so storm flow does not separate them, and support the route to avoid low spots that retain water and debris.

For buried drainage, confirm outlet location, cleanout access and responsibility for blockage. Hiding a pipe underground does not improve performance unless the line has a reliable fall and open termination.

Details to confirm before hiring

• Does grade continue away from the endpoint?
• Can the extension remain connected during heavy flow?
• Will it create a trip or mowing hazard?
• How is erosion controlled?
• Where does a buried line terminate?
• How can the route be cleaned or repaired?