Residential Drainage

June 7, 2011 — 18 Comments

The average amount of rainfall in across the US is 35″. Depending on where you live, that might seem like a little or alot. Dallas (the center of the Universe) is right at the average with 34.73″. Drainage around your house should be taken seriously, otherwise the results can be prohibitively expensive to repair. I have some drainage issues at my own house to deal with and a few weeks ago, I took the first step to dealing with it.

I don’t have gutters on my house so everything just spills out into the yard – which in and of itself isn’t a problem. The grading on the back side of my house has a low spot and we have a Ryerson steel edging containing a decomposed granite foot path. As a result, every time it rains, the back half of the yard becomes flooded and holds all the water in. Eventually the grass rots and you are left with this:

Backyard Drainage Before

Not very attractive is it? And the very best part is (very sarcastically) is that this null void of lawn just happens to be the preferred place of waste relocation for the dog(s) so I was guaranteed to have dirty, muddy dog feet to deal with.   This is actually the third time we have gone through the process of bringing dirt in and laying down new sod … and it always rots and dies. So I had a conversation with my back about our options.

Bob: We need to install an area drain, dig a trench with a PVC line out to the alley, and put in a pop-up emitter … or this grass is never going to grow here.

Bob’s Back: What do you mean we? I think “we” know who will actually be doing all that work. Me.

Bob: I don’t think I need to tell you that things are tight here at the Borson house and this needs to get done.

Bob’s Back: Please … you don’t know what tight is! If I have to dig a trench and lay 1,000 square feet of sod you’re going to get a new appreciation for the definition of “tight”.

Bob: I’m open to ideas, talk to me in a non-threatening manner and maybe we can come to some sort of arrangement.

Bob’s Back: Why don’t you spend some of that ‘Life of an Architect’ money and hire someone else’s back to do it.

Bob: Ooooo, that is a good idea … except there isn’t any ‘Life of an Architect’ money – sorry to disappoint you

Bob’s Back: Well, you are just going to have to talk to moneybags and convince her that this is the right thing to do. Nobody wants me to act up and bring the pain. Or do they?

Bob: (eyebrows raised, hopeful face)

Bob’s Back: (scrunched up eyebrows, irritated face)

Bob: Fine. You win…… (shouting) Michellllllle! (sing song-y voice) I have a question for youuuuuuuuu…..”

So I hired someone else to do all this work. I called the good folks over at Dallas Curb Appeal and they came out, gave me a “fans of Life of an Architect” website price (in other words – no break) and that was that. I also figured that since they were there, they might as well scrape off the grass weeds in the front yard and lay sod in that area as well. Ever since the great flood of July 2010 (post and pictures here) when a city water main broke and flooded my front yard, so much crappy dirt was washed up and deposited in the yard that all the grass died and nothing but the hardiest of weeds took up permanent residence.

preparing the dirt

Holy Moly!  Do you see that guy all bent over with the shovel?!? That could have been ME! In an effort to edumacate you (the reader) – let’s take a closer look at what’s happening using a special filter on my camera (it’s called the “Pain-o-meter” filter if you’re interested in picking one up):

Guy Bending Over pain-o-meter

Yeah – that wasn’t ever going to get done if I had to do it. So the basic scope was to install an area drain, digging a trench, and lay some PVC piping (none of the flexible black NDS pipe for me thank you) connected to a pop-up emitter located in the alleyway.

Backyard Drainage After

NDS pop up emitter detail

The week immediately following the installation of my new drainage system it rained 6.31″ in Dallas (scoreboard) and the water was effectively removed from the yard (hooray!).  Here is look during a brief break in the storm (you can see the 8×8 black area in the bottom middle of the photo.

Backyard during storm

And here is my yard  two weeks later:

Backyard Drainage After

There are some very standard methods and techniques that you can take advantage – they all involve conveying water away from your house in a controlled manner. Whether that is through perimeter drainage pipes that collect runoff water and put it into the storm water system, or the more ecologically friendly method of slowing down the release of the water back into the ground – if you aren’t controlling how water moves around your house, you probably need to take a closer look at what’s actually happening.

A practical graphic can work wonders to help identify and explain the different methods available for controlling water runoff. I did not create this graphic (you think I would design a house that looks like this one and use it as an example? Please…). Special thanks to the City of Kirkland, Washington for allowing me to use their graphic.

Property Sketch with Drainage

  1. Foundation drains divert stormwater away from your building’s foundation. Foundation drainpipes are perforated and usually surrounded by gravel. The pipes disperse the water (instead of discharging in a concentrated area) and the gravel contributes to infiltration of the water. The gravel can be wrapped with a layer of filter fabric to prevent the drain from clogging with sediment.
  2. Roof drainpipes are not perforated, and are not connected to the foundation drain system. They should be connected to convey water to the City’s storm drain system, to a drywell, or directly to a waterbody.
  3. Gutters collect runoff from a building’s roof. This runoff is conveyed through downspouts to the roof drain system. Gutters should be kept clear of leaves and other debris so clogging does not occur in the roof drain system.
  4. Storm drainpipes convey rainwater to the City’s stormwater system. Storm drainpipes can be made from many different materials such as concrete, aluminum, and polyvinyl chloride (PVC).
  5. Catch basins are connected to storm drainpipes. They are concrete structures (either round or rectangular) with metal grates on top. Catch basins capture debris that could clog the pipes in a storm drain system. You can prevent the system from clogging by checking the catch basins in your neighborhood during and after a heavy storm. Use a broom or rake to remove any leaves or debris that have blocked the catch basin’s grate.
  6. Yard inlets are similar to catch basins but are much smaller. Metal and plastic yard inlets can be purchased at a local hardware store.
  7. Trench drains are used to capture stormwater flowing over a larger area like a driveway. Trench drains convey rainwater to the City’s storm drain system.
  8. French drains can be installed anywhere on your property that collects water. French drains are constructed with a perforated pipe. Gravel and filter fabric surrounds the pipe, similar to foundation drain systems.
  9. Drywells can be installed in areas that cannot be connected to a stormwater drainage system. Drywells are filled with gravel and surrounded by filter fabric. Water flows into the wells and infiltrates into the ground through the gravel.
  10. Cleanouts are designed as easy access points for maintenance of the stormwater drainage system. They are usually located in a bend where debris can clog the system.




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  • Neal P

    How’s that drainage holding up? We don’t get that much rain here in my part of CA, but drainage is an important issue. My place has gutters that go underground to a drainage system, which takes all the water out to the street. I’d like to find a way to capture that water and store it for watering.

  • Loved this. Going to refer my Architectural Drafting students to it for their enjoyment and clearer understanding of drainage…  Thanks Bob.

  • Loved this. Going to refer my Architectural Drafting students to it for their enjoyment and clearer understanding of drainage…  Thanks Bob.

  • Loved this. Going to refer my Architectural Drafting students to it for their enjoyment and clearer understanding of drainage…  Thanks Bob.

  • Informative and hilarious (especially the pain-o-meter; made me cringe and giggle all at the same time).

    • I keep the pain-o-meter at the ready at all times. You can never be too prepare to demonstrate why you shouldn’t do manual labor.


  • Anonymous

    I’ve always heard that the rule is to grade your yard so that the water drains away – into your neighbor’s yard.

    • I know you are being funny (because I laughed) but for those who don’t know this:

      You can not change the grade at the perimeter of your property. If your neighbors yard slopes into yours and you don’t like his runoff coming onto your property, you can only deal with this on your your side through swales or berms. What I mean to say is that (if you read Doug’s comment below this one) if you build a berm, it has to start and stop and provide room for the conveyance of water on your side of the property.

      Here is a quick sketch to help show what I mean;

      • architectrunnerguy

        I erred when I said there’s “zero cross property water flow now”. You are correct in that all grade modifications have to be done on your side of the property line. Well, since my 4″ high berm is 24″ wide, there’s 12″ sloping toward his property, meeting the original grade at the line. And where that water is going actually came up once.


        • I wasn’t calling you out – I knew what you were saying. I just thought it best that we take a moment and clarify for all the non-architect readers.


  • architectrunnerguy

    Another critical factor in residential drainage is water flowing from one yard to another. Or in my case, perceived to flow from one yard to another. To placate my neighbor I finally built a 4″ high by 2′ wide berm the entire 250′ of the shared property line. Ooops!! Correction, I didn’t build it, my back did. Zero cross property water flow now. And exactly as I predicted, he still has ponding.

    Of course my neighbor is utterly convinced that the steeper the roof, the more water it sheds (We rebuilt our house. Same exact footprint but changed the roof from a 6:12 to a 10:12 and he thinks there’s significantly more water coming off of the roof). But the berm makes all that moot anyway.

    But nice job Bob. All you need now is some glass block light fixtures.


    • you should have built that berm out of glass blocks and then buried them in dirt – the symbolism alone would have righted a few wrongs in this world.

      Your neighbor would drive me crazy with his thinking. He does know that rain falls from the sky and the slope of your roof doesn’t change the amount of water that lands on it in the first place.


      • architectrunnerguy

        Anybody beyond the second grade knows that except for this guy. It’s like explaining to someone the sun rises in the east and they insist it rises in the west. At least it gave me a great deal of credibility when he was explaining the steeper roof=more water to the county grading inspectors when they showed up responding to his complaint.


  • Raina @ If the Lamp Shade Fits

    Bob’s Back is wise in the ways of the world.