Quick verdict
Two 24 inch plastic splash blocks that sit under a downspout outlet and carry roof water two feet away from the foundation on a 15 degree slope, with a stepped ladder surface that sheds dirt instead of holding a puddle. A splash block is the lowest-effort fix for water pooling at the base of the house, and two feet of extra distance stops the erosion channel and the damp basement corner that a bare downspout causes. They sit on the surface and move if kicked; set them in a shallow bed of gravel.
Strengths
- Moves roof water two feet from the foundation with no digging
- Fifteen degree slope keeps water flowing, not pooling
- Stepped surface sheds silt and leaves
- Two blocks for two downspouts
- Light plastic resists frost and sun
Weaknesses
- Two feet is the minimum useful distance; flat clay sites need more
- Surface blocks shift if kicked or mowed against
- Plastic can crack under a heavy boot in frost
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Two Feet Makes a Difference
A downspout that ends at the wall drops hundreds of gallons at the foundation in every storm, digging a hole and feeding the damp corner in the basement. A splash block is the oldest and simplest fix: a sloped trough that catches the water and sends it two feet out. NAACOO’s are 24 inch plastic blocks with a 15 degree slope and a stepped surface that sheds dirt, two to a pack.
This review is based on the listing specifications and on how downspout splash blocks perform generally. We have not used these blocks ourselves.
Setting It
Scrape a shallow bed under the downspout, level it and add a handful of gravel. Set the block with the high end under the outlet and the low end sloping away from the house, press it in and check that water will run off the end onto ground that falls away. Bed it slightly below lawn level so the mower passes over. Five minutes per downspout.
What It Does
Water lands in the trough instead of on the soil, runs down the 15 degree slope and leaves two feet from the wall. The erosion hole stops forming and the soil against the foundation stays drier. The stepped ladder surface is a small improvement on flat blocks that hold a puddle and a layer of silt.
Limits
Two feet is the start of good practice, not the end. On flat clay that drains slowly, water still soaks down near the house, and a buried pipe or a longer extension does more. For a sloped lot with soil that drains, a splash block is often all that is needed.
Durability
Light plastic shrugs off frost and sun. It cracks under a boot in winter and shifts if kicked, which is why bedding it in gravel matters.
Who Should Buy It
- Homeowners with downspouts ending at the wall.
- Anyone with a sloped lot where two feet of carry is enough.
- Renters and quick fixers who will not dig.
Common Owner Complaints
Blocks that moved and water that still pooled on flat clay. Bed them; add length where the ground is flat.
Technique Tips
Check the ground beyond the end of the block falls away from the house; a block that discharges into a hollow has moved the puddle two feet, not removed it. Extend the downspout with an elbow so it discharges onto the high end of the block rather than beside it. After the first heavy rain, look for a channel forming past the block end and add gravel there.
Alternatives to Consider
The NAACOO catch basin and stretch pipe carries water up to 8 feet on the surface. A buried 4 inch line to a pop-up emitter is the permanent fix. A rain barrel captures the water instead.
Verdict
For a downspout on a lot that drains, a splash block is the cheapest effective fix and these two are a sensible design. Bed them in gravel, slope them away and the hole at the wall stops growing.
Full specifications
NAACOO 2-Pack 24 Inch Downspout Splash Block with 15 Degree Slope and Ladder Design FAQs
Yes, within its limits. It stops water dropping straight down at the foundation and carries it two feet out, which prevents the erosion hole and reduces water against the basement wall. On flat clay a longer extension does more.
Scrape a shallow level bed, add a little gravel, set the block with its high end under the downspout and its low end sloping away, and press it in so it does not move.
Flat blocks hold a puddle and silt. The ladder steps let water run and dirt wash off, so the block stays clean.
If the block sits proud of the lawn, yes. Bed it slightly below grade at the edges.
