Learned that French drains need a specific slope or they're useless

I was digging up part of my backyard to fix a soggy patch near the fence, and my neighbor came over to help. He told me French drains need at least a 1% slope, meaning a 1 foot drop for every 100 feet, or they just let water sit and clog up. I had no idea I needed to be that precise, figured a slight angle would do the trick. He showed me his setup with a level and a string line, it was way more math than I expected for a simple trench. Anybody else mess this up their first time and have to redo it?

3 comments

3 Comments

lee84714d ago

My neighbor's the same way with his gutter downspouts, spent an entire Saturday with a transit level and a laser just to get a 10 foot run right. I just eyeballed mine and hoped for the best, still waiting for a big rain to see if I messed up.

fiona_west2111d agoMost Upvoted

Eyeballing it works fine if you know what you're doing, you'll be alright.

nathan90114d ago

30 bucks says the first big rain reveals you got a 1% slope going the wrong way, and now your foundation is gonna get a nice shower instead of the lawn. I mean, at least the neighbor got a cool laser out of it, right?