I recently had a sink hole in my backyard that I consulted with here on DIY and got some helpful responses. This was as a result of an old well. It was fixed by a landscape architect.

However, after some more heavy rain I can now see other issues that my back yard is having with drainage. Can anyone recommend additional drainage fixes?

Along the side of the first picture I have three french drains. Those drains hook to a larger drain that goes to the main neighborhood reservoir. They do not seem effective though, and neither does the mulch as it just flows downward. Water flows onto the deck posts and soaks them, as well as along the back line of the yard and down to the lower side as you can see in the pictures. I am thinking this is where the issues lie - need a better solution here.

In the second picture (yes I know, its blurry but it was raining heavily) you can see some standing water in the grass which I have highlighted. Some water flows along the back fence/grass line which is fine. I obviously can't force a drain line to flow into my neighbors yard as this is illegal.

That water all comes down along the fence line next to the neighbors house which sits lower than mine. It piles up along the side of my house as you can see in the third picture. Maybe that needs some french drains as well?

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  • Make sure your neighbor isn't pointing all of their drainage at your fence line and just shoving it onto you. Are you sure your french drains aren't blocked? Dec 28, 2015 at 17:48
  • Eventually the water drained into the drains but when it is very heavy rain they seem to fill pretty fast. The neighbor on that side is worthless - he has no gutters, no drainage plans that would flow water correctly. Dec 28, 2015 at 18:02
  • 1
    French drains are not supposed to slowly drain, nor hold water like a catch basin. You need to clean them out and have someone make sure they were properly installed with drain pipes sloping downward toward their discharge. There looks to be a decent amount of slope toward where the water is pooling but no slope away from that area, slope everything away from your house and toward somewhere off your property. Dec 28, 2015 at 19:19

4 Answers 4


I had nearly the same problem and a single french drain made the problem go away. It is important (and probably worth reinstalling if not done) to have:

  • a 10% grade (1 inch down for every 10 inches of pipe length)
  • cloth covered french drain pipe
  • plug off the yard-end or open it to a ground level drain (cloth and grate covered!) and make sure you can access it to clean it out
  • make sure your trench is at least 8 inches wide (2 inches clearance on either side of a standard 4 inch french drain pipe)
  • place the french drain pipe in a channel that has 1-2 inches of pea gravel for a bed
  • cover the pipe with at least 2 inches of pea gravel before putting in the dirt

The french drain also should start prior to the onset of the wet area. (Please note the image does not accurately reflect the opening of the yard end - i.e. you can't clean this one out!) french drain diagram


I had this exact same problem when I purchased my house four years ago. 90% of my gutters drained to the side of house along with along with 90% of my neighbors gutters. To further complicate the issue my neighbor has a ton of tall bushes that shade the area, so any time there was a heavy rain water would sit there for up to 3-4 days. I put in a french drain exactly like b-p suggests above, EXCEPT I ran the french drain all the way down the side of my drive way to the curb with a pop up valve on the end. I haven't had the slightest puddle of water there since then.


With heavy rain it takes time for the water to filter into the French drain. (Water making it through the roots and dirt over the drain) The distance & slope also affects the speed that the pipe can empty. One additional drain on your side yard to the reservoir should help eliminate the standing water there.as long as the reservoir is not full. As others have suggested make sure they have not filled up with dirt, I like using the pipe that has a sock on it to reduce the dirt entrance (it moves through the gravel over time).

  • I got the side of the house sloped before I moved in so rain would not get into the crawl space. I think maybe gravel that's covered by rock would help as dirt and mulch may be getting into the drains. Thanks for your help! Dec 28, 2015 at 20:16

Oh another oldie & surprise-surprise another moldy "professional". Pitiful! What no Warranty? Yep, you got the "Landscape Architect" treatment alright. Another waste of money on a Certified & Degreed horrible idea. That ain't no French Drain that's dumb Drain Tile (a dumb name too).

Always try nature first & foremost! Since there's a downslope to a reservoir then there's a down slope to fix both properties permanently. It's called a swale or gully & it doesn't clog up & the water's already done half of it for you! Another "secret" is that you can bring dirt in to make a slope or make it a bigger slope...truly amazing!

Build-up the back or if that's lower than the houses too, take dirt out & put it between the houses as the high point. And, the front just needs to be taken down to the curb. You can see the water wants to go there, but it can't. Most everyone needs a Land Sculptor & most no-one needs a Landscape Architect!

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