Stormwater runoff: a failing grade
September 24, 2017 7:49 PM   Subscribe

What is the quickest and easiest way to keep water from pooling near our house when it rains without using heavy machinery or hauling away huge piles of dirt? Three sides are pretty manageable, but the fourth slopes down from the alley toward the house and looks like this.
posted by sibilatorix to Home & Garden (10 answers total) 3 users marked this as a favorite
If you can dig a small trench that can carry the water to the adjacent sides, and then use the excavated dirt to back fill the foundation? They sell perforated pipe in a mesh bag that can provide an easy to make trench for collecting water in situations like this. Just digging down a little so the water can turn the corner at the edge of the house might be enough to get the water moving around your house.

Can you tell where the water comes from? If it is the alley, look at building a small berm to keep it up there. If it is your own roof drains, consider dropping them into pipes that lead around the corner to the better draining sides.
posted by nickggully at 8:01 PM on September 24, 2017 [1 favorite]

If I were in your situation, I'd probably consider installing a french drain.
posted by RichardP at 8:24 PM on September 24, 2017 [8 favorites]

+1 to nickggully's comment. Additionally, you need a clear & definite earthen slope AWAY from the house's foundation out maybe 3-4 feet at least. Right now, you have a slight/barely noticeable slope away from the foundation for maybe 6 inches or a foot.

A somewhat ambitious person could probably get this going with a simple shovel and an hour's work or so, simply by moving dirt in the high area to the right of your photo into the low area to the left of your photo. It would be especially easy when wet or damp (easiest--when just a bit damp but not soaked. Hardest--when completely dry & hard as cement).

Basically you want the high area to the right side of your photo to be the lower-lying area where the water will flow, and the higher ground area to be right next to your house where the water is now flowing.

Note that this a general principle--water needs to flow downhill from your foundation for at least several feet--and I only have the photo to go on, so my solution might possibly cause more problems (What is the right of the photo behind the fence? What is behind it?, etc . . . ) but definitely something to think about.
posted by flug at 8:44 PM on September 24, 2017 [2 favorites]

Also, my stock answer to this type of situation is: make sure to go outside RIGHT DURING an actual rainstorm and carefully observe where the water actually comes from and where it actually flows.

This will suggest many solutions to you. Take a shovel out in the rain & start to implement them immediately--you'll be surprised what moving a few shovelfuls of dirt can do, once you see the actual exact situation on the ground.
posted by flug at 8:45 PM on September 24, 2017 [6 favorites]

I've had this situation in a couple of houses I've remodeled. Looking at yours, I think I'd consider sloping the ground down and away from the house at least four or five feet out and installing a retaining wall/planter at that point to the current ground level. A French drain would be installed behind the base of the retaining wall. Starting at the center of the length of wall, it should slope slightly down and then around your house to move the water away from the foundation. Where we live it freezes in the winter and we have a lot of snow that puddles up when it starts melting in the spring, so we ran heat tape underneath the entire length of the French drain. When the snow started to melt, we would turn on the heat tape for maybe an hour - just long enough to get a stream of water moving through the melted ice. The moving water should keep the hole open unless you get another deep freeze.
posted by summerstorm at 10:21 PM on September 24, 2017

It's hard to know from just one photo, but you will probably want to do either of several things, including reconfiguring the surface of the ground such that water flows away from the foundation and there is a path for water to run off in some direction rather than ponding, changing how the gutters drain, and/or installing a french drain (which may be simple or may be complicated, depending on the overall slope and configuration of your yard, options for dealing with the collected water, local regulations, etc).

Is that silt fence at the back of the yard, or just some kind of temporary garden fence? It looks just enough like silt fence to make me wonder if there has been more construction work going on, and if the issues might be more complex.

It also depends on if this is a house you own vs a rental -- if it is a rental, your options may be more limited (as well as you willingness to do major work being limited, obviously).
posted by Dip Flash at 5:35 AM on September 25, 2017

It all depends on whether you have access to a place for the water to go, downhill somewhere. If so, a trench or buried pipe (French drain, as mentioned) will work. With no easy downhill available, you would have to fill with soil to raise the ground level.
posted by SemiSalt at 5:53 AM on September 25, 2017

It all depends on whether you have access to a place for the water to go, downhill somewhere. If so, a trench or buried pipe (French drain, as mentioned) will work

The other option with a french drain is to run it to a dry well -- but that requires having the space, soil with good percolation, and local regulations allowing it. It's also a lot of digging which the asker is hoping to avoid, but pretty much all of the drainage fixes are going to require moving dirt.
posted by Dip Flash at 6:32 AM on September 25, 2017

Response by poster: Thanks for the advice!

I guess the photo doesn't show it, but the ground does slope away from the house for about four feet; it's just covered by puddle. The puddle used to form right up against the foundation; we moved a fair bit of soil to get it to this point. I'm pretty sure at least half the water is just what's falling on the ground, though some is also coming from the garage roof behind the camera - we're about to install gutters to direct that water toward an area with better-drained soil.

Dip Flash - You're right, that is silt fence. The house is ours and is nearly built - we're trying to get this grading done so we can put down mulch for erosion control, one of our last few inspections.

I guess pending other options we'll try to extend the slope away from the house and see if we can make it drain to the landscaped area on the far side of that silt fence - unfortunately, the ground on the other side of the silt fence is fairly high... we'll see how it goes. A french drain or similar might be necessary, but we don't have a very good location for it to drain to unless we construct a drywell or rain garden - yet another project!
posted by sibilatorix at 3:12 PM on September 25, 2017

A couple of notes:

(You may already know this, but...) Never pile dirt up any higher than the concrete foundation on the side of the house, covering brick/stucco/siding with dirt is inviting damage to the walls from moisture. This may limit your options as far as re-grading near the house.

I'm wary of the complexity of french drain schemes. Done incorrectly they can clog up with silt and not work very effectively after a few years.

I have some personal experience with a small backyard which is between my house and a compacted gravel alley. It used to puddle terribly at every major rainfall. Since I've done a lot to loosen up the soil and enrich it with compost and plant things other than grass there, it has become a lot better at absorbing excess water, now the puddling is usually less frequent than once a year and doesn't last more than an hour or so. If necessary, some kind of trench/swale/rain garden some distance from the house may do a good job of catching this water for long enough that i can be absorbed.
posted by mmagin at 4:13 PM on September 25, 2017 [1 favorite]

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