Drainage Work: U-Channels, Stone, Gravel & Pipes

About a year ago, I purchased a traditional Japanese house in the countryside at the base of a mountain. Every time it rained, water flowed down from the mountain and pooled against the foundation. This drainage project was the first exterior work I did after buying the house.

Digging the Trench

I dug a trench along the foundation of the house. The soil was full of massive rocks that had to be split and removed piece by piece.

The Problem: Water From the Mountain

Water from the mountain would collect against the foundation on rainy days.

Installing U-Channels and Drainage Pipe

I laid concrete U-shaped channels along the trench to catch surface water, and connected drainage pipes to carry it away from the foundation toward the road.

The project took several months, working on it between jobs and on days off.

Completed Drainage System

After installing the U-channels and drainage pipes, I filled the trench with gravel to allow water to filter through while keeping the area walkable. The stone wall along the foundation helps retain the gravel and adds structural support.

Now when it rains, water from the mountain is captured by the U-channels and directed away from the foundation through the drainage pipes. No more pooling water against the house.