A Simple Trench Drain

59 responses

  1. Michael R. Bakalis
    December 15, 2012

    Hello Tim, I have gone ahead and began construction on my trench drain. It is on the east & south side of the house.Have used the 3" rigid pipe with holes(facing down).The line to daylight has a descent slope to it. I am also using this trench to daylight to run the 1 1/2 " sump pump discharge (solid)layed it right on top. My question is: I also would like to tie in the gutters to to this trench to daylight,by laying another 3" rigid (no holes) pipe next to the sump pump line,and then covering all with stone.It would save the work of making another trench.Would this be alright?

    • Tim Carter
      January 3, 2013

      Mike, you should consider investing in a 15-Minute Consult with me. Look at my cart for that. Lot's to discuss. I just do short pithy answers here.

  2. scott
    December 26, 2012

    Help! How can I find a landscaper in the Baltimore area to do this? This sounds like exactly what I need to stop the water coming into my crawlspace.

    • Tim Carter
      January 3, 2013

      Scott, you need to do a 15-Minute Consult with me. Look at my cart for that. I can tell you how to find the right person.

  3. jeanne howard
    February 7, 2013

    Your instructions installing the drain pipe after digging the two foot trench indicates tamping down the soil, adding one inch of rounded gravel before lowering the pipe and then covering with "gravel". Is the top layer of gravel a different type than the rounded gravel?

    • Tim Carter
      February 24, 2013

      No. But it can be. It just needs to be very permeable.

  4. steve notari
    February 16, 2013

    Hi Tim, I own a 2 family house, the 2 apartment are built side to side,
    in the basement I have 2 sump pumps, one on each apartment, we
    have a 3rd pump outside a few feet away from the house, we have a
    lot of water in the ground.My question is this, are the 2 pumps in the
    basement connected? in other words if one pump stop working, does
    the other pump do double the work? I live in New Jersey.
    Thank for your time, Steve

    • Tim Carter
      February 24, 2013

      If I understand you, the second pump works. It will pump as long as there is water and electricity.

  5. janet
    March 15, 2013

    HELP! We own rental property and have installed about a half-dozen French drains - all successful. We did one last week-end on a new piece of property. The drain is excellent; doing it's job to perfection. However, the dry well is overwhelmed and is causing the the water to back up into the drain pipe. We knew this was a possibility and we installed the dry well with a straight shot to the street if the worst happened. Now we have to tap into the system and take it to the street. Should we install a lower pipe in the dry well, or should we cut the drainage pipe a few feet back from the dry well and tap into it there?

    • Tim Carter
      April 1, 2013

      Janet, Walter, this is what my 500-Second Consult is all about. Click the Shop icon at the top of the page!

  6. J. Stanton
    March 29, 2013

    What do you do if there is no where to extend an open drainage pipe? Can you extend the pipe to a large gravel filled well-like underground hole? We live in a city surrounded with street and curbs in the front, paved alley in back and neighbors on both sides.

    • Tim Carter
      April 1, 2013

      There is almost always a low spot to daylight the pipe.

      • joe fischer
        December 9, 2014

        Hi, J. Stanton's question applies for a house I am considering buying. Basement gets water, ground gets quite wet, gutters not working well now (before purchase) and neighbor says previous owner pumped water to street, it iced up, other neighbors complained.
        If I were to install a linear French drain as you recommend there is no place where it could open to daylight given the layout of the land. Could it go to gravel pits?
        Also, the basement door opens to a concrete slab that collects water and appears to have no drain, and whose level is below where the French drains would be. Any ideas to fix this?
        Thanks, JF

      • Tim Carter
        December 9, 2014

        Gravel pits in the ground FILL with water as the ground gets saturated. They're USELESS and a folly. Don't buy a house with drainage issues. Go find another place.

  7. Joldy
    April 15, 2013

    How long should a French drain be? In all of the articles I've read they talk about height and width of the drain but not about length. There must be some guidelines or formula for square feet of roof plus average gallons of rain coming off the roof plus type of soil = length.

  8. Joldy
    April 15, 2013

    How deep and wide should a drywell be for removing rain from a gutter/downspout? Deeper and wider I'm sure would be better. We live on top of a sand dune, so the drainage already is good.

  9. Dan Porter
    June 27, 2013

    Can I ask why you do not recommend wrapping the pipe/gravel in any sort of pipe sock or landscaping fabric? I am installing a very similarily designed trench drain to yours, however, i was going to use a pipe sock, as well as wrap all the gravel and pipe within landscaping fabric.

    • Tim Carter
      January 15, 2014

      I cover this in my Linear French Drain DVD!!

  10. Peter
    August 8, 2013

    French Drains and Geo-Fabric? I am installing a French Drain and noticed that in your article, you didn't mention the need for geo-fabric to line the trench. Is the fabric necessary or a drain sock?

  11. Peter Ahern
    October 23, 2013

    Okay, once the drain pip is installed the water will enter it and travel down the grade to where? Do I terminate to a gravel bed, just let it open end and flow downhill into the yard (We live on a slight hill, thats a part of the original problem) or what? This might fit into the "stupid question" category but I'd rather appear a fool than hire some contractor to fix my mistakes. Thanks!

  12. chris
    January 11, 2014

    what is causing water to come to the surface and run all winter months and freeze and thaw when warm .this is causing troubles to the side walk out front of my home .the water runs across my neighbours yard down across to my front yard .is there a under ground stream causing this .its getting bad because its been very cold this winter here in Dartmouth nova scotia .what can be done about this before there is lawn and home damage along with pedestrian's getting hurt on the side walk.
    thanks .Chris...

  13. james
    May 25, 2014

    Hi, I done a french drain in one of my customers yard, she wanted me to take it to the end of the yard to drain out towards the street. I would like to exit the water in the middle of the yard pass the problem area. There is a down slope there! Would this be wise to do. That way I don't have to cut through all her sprinkler pipe, she wants me to go under the sprinkler pipe without cutting it. Please help! thanks

    • Tim Carter
      May 25, 2014

      Lots to discuss. You need to schedule a 15-Minute Consult with me. See the SHOP icon at the top of the page? Click it. Go to Consult Tim in the left column.

  14. Adam
    June 10, 2014

    Tim, it's been recommended to me that due to the volume of water I receive I ought to lay 2 pipes in my french drain. I also plan on running my gutters in a closed pvc pipe in the same trench. Is it okay to lay the 2 perforated drain pipes toward the bottom sides (3" from each side in a 18" wide trench, 24" deep) and the single gutter drain centered above. The 3 pipes forming a sort of triangle?

    • Tim Carter
      June 11, 2014

      That's fine. One 4-inch pipe will handle VAST amounts of water. I can't imagine you needing two.

  15. Gokul dahal
    October 15, 2014

    Hi Tim! I have sumpump in my basement I don't have any problem last year but from past January my sumpump run every 5 to 10 sec and discharge 10 to 15 gallons of water every min .i call the basement guy to fixed , they told me this is spring water and I check the water in lab if there is any leek of public water the result is spring water. How can I solve this problem?

    • Tim Carter
      October 15, 2014

      Purchase my Linear French Drain DVD and put one in at your home.

  16. Kathryn
    November 25, 2014


    My home is in a suburban city where the homes are very close to the neighbors. I have about 2' from my foundation and the neighbors driveway. Would a trench drain work here or would it actually direct more water towards the home?


    • Tim Carter
      November 26, 2014

      I'd have to see photos and possibly a short video to fully understand all the dynamics of both overland and subsoil water movement in and around your house. A 2-foot small area next to the house is not much to work with, that's for sure!

  17. laura
    December 17, 2014

    I have a very simple basic question. How big should be the holes in the perforated pipe and how far apart? Would two rows of 8mm 80mm apart at 120 degrees would do? There are only solid plastic pipes on sale here. Many thanks

    • Tim Carter
      December 17, 2014

      Laura, Yes the measurement you give will work. I'd put them though at 60 degrees not 120!

      • laura
        December 17, 2014

        Thank you, I meant 120 degrees between the rows, so, 60 from the lowest point?

      • laura
        December 17, 2014

        or 60 between the rows?

  18. Jason Ratliff
    January 10, 2015

    I recently bought a home via an estate sale where there was significant water intrusion and mold in the crawlspace. The sellers agreed to spend $8,000 for a french drain around the entire interior crawlspace perimeter, a sump pump, 15 mil vapor barrier, and a santa fe dehu. We were told that this was common in the area, and that this would take care of the issue. The house is U-shaped with a courtyard design, and the crawlspace floor is on average 4 feet below ground level (2600 sq ft). All gutters are clean and downspouts are diverted 6-8 ft away from the foundation. All that being said, water is seeping through the block around the entire crawlspace. wondering if the linear french drain would help? The fact that the crawlspace floor is 4 ft below ground level leads me to believe that the drain may not catch this water. A landscape architect mentioned that the house could have possibly been built on a spring due to the extreme sogginess in the backyard and parts of the front. After 45 years I would have expected there to be significant damage if that were the case. The landscaping is also original to the home. Would these roots be aiding in the water intrusion as well?

    Greenville, SC

    • Tim Carter
      January 11, 2015

      A linear french drain WILL SOLVE the problem. Purchase my DVD that shows you step-by-step how to install it correctly.

      • Jason Ratliff
        January 11, 2015

        Will do Tim. Do you recommend that I dig to the footer (4 ft)? Or will your recommended 2ft depth suffice? The problem is that I don't know if it's ground water or surface water that is penetrating. I just want to make sure that I get this right the first time.

  19. Jeff
    January 30, 2015

    Tim, i have a sump pump that runs constantly. When the power goes out if i have to make sure the generator runs or i will get flooded. Can these linear french drains help me. I'm told my problem is with groundwater. In other words if the water is coming up from under the foundation. Would a french drain help?

    • Tim Carter
      January 30, 2015

      Jeff, if you send me photos of your situation and schedule a phone consult with me, I'll be able to give you a Yes or a No. All my consults are MONEY BACK Guarantee. Purchase this phone consult and then send me photos.

  20. Max
    February 4, 2015

    I had a french drain installed last week to fix a problem with water pooling beside my foundation. I also had gutters installed. It rained two days later and water pooled up once again, right over where the drain went in. It took about 24 hours for the water to drain, and it's still terribly muddy. How long should it take for a french drain to drain away a pool of water?

    • Tim Carter
      February 4, 2015

      Immediately if it's put in correctly. Sounds like you need my Linear French Drain DVD....

  21. Stephanie
    March 13, 2015

    Hi Tim,

    I live in Southwest Louisiana where the land is pretty swampy. I am having trouble with water pooling in the crawl space and loosening the soil underneath the blocks, resulting in a sagging kitchen floor. Not sure exactly how deep the water table is- my question is do I go ahead and dig the trench 24" deep regardless or should I stop an inch (or more) above where I hit water?

    Thanks for the great information!

  22. Drainer
    March 27, 2015

    Im no expert but have some info that may help. Water tables are not static, especially a perched water table. You should dig your trench at least to the depth of your footing.
    However, It is difficult to dig in a muddy water filled trench. Start digging until you hit water. Then dig that trench downgrade...the water will drain away. It may take a few days or more depending on how saturated the ground is. Once the mass of water is gone dig deeper, if you hit water again repeat the process.

  23. Kiran
    April 3, 2015

    I live in a ranch home in Decatur, GA, and have been wrestling with drainage problems for years now. As with most people in the area, rain always means a wet basement. I have identified the location where the water enters the house, and have considered an interior patch solution. However, common sense says that trying to patch from the inside is only a temporary fix - the water will eventually push through. Ideally, I would like to run a "U-shaped" french drain all around the outside, but there's a driveway and built up front porch which would prevent me from doing that. One basement waterproofing consultant suggested an interior french drain leading to the sump pump, which I found ridiculous. Isn't the idea to keep water out of the basement? Any suggestions would be much appreciated!

    • Tim Carter
      April 3, 2015

      Correct. Kiran, you need my Linear French Drain DVD. CLICK HERE to get it.

  24. Chad
    May 4, 2015

    I just installed a french drain on my property. Water is now saturating the soil at the end of my french drain. I feel like I just moved my muddy mess to a different spot in the yard. It's been 2 days since I installed it. Any suggestions?

    • Tim Carter
      May 5, 2015


      I pretty much tell you in this column and all my other articles about this topic that the pipe should daylight at the lowest part of your lot. It appears you missed that part.

  25. Danny
    June 26, 2015

    Hi Tim!

    Thanks for the excellent article on french drains. I have a drainage problem with my townhouse. There is an area in between my home and the next home that is pretty flat, about 30 feet long and 11 feet wide in between the houses. During the rains, most of the water pools next to my wall, so there is a slight slope towards my house. I had a few contractors come and give me a solution, and one was a french drain dug only 12 inches from the foundation of the building, the 12 inches of area re-graded and the french drain dug 12 inches wide and 12 inches deep. My concern is that 12 inches is too close from the house and that there will not be enough slope in the area (which is pretty flat) to drain to daylight... Any suggestions will be greatly appreciated.

    Thank you!

  26. brian
    July 9, 2015

    Would this work if my house is sitting on sand? I've been getting water in my crawl space. I got a sub pump at the lowest point in the house just not drainage pipes.

  27. Kevin
    September 16, 2015

    Hi there i am having some floor drain issues in my basement on a house build in 1947 the floor drain was backing up i took a shop vac and was able to release whatever it was that was clogging trap however when i removed the cover i found that the trap has a cleanout plug with looks unable to remove all rusty but there is another hole on the other side of cleanout that is just open and when it rain hard the water will come out of that hole like a geyser and go into the floor drain what could this be?

  28. Lachlan
    January 15, 2016

    Hi Tim,

    I have water puddles under my house. I live in Australia and I am interested in getting your DVD video and/or getting you to consult.

    If I buy your video can I then download it?

    Can you consult over Skype?

    • Tim Carter
      January 15, 2016

      Yes I can consult via Skype. I do it all the time. I can send you via mail my Linear French Drain DVD. I emailed you all the information and pricing for international postage.

  29. Donald Tinsley
    February 15, 2016

    I have a single story home built in 1999. I am the second owner. The original owner states that since the home was new that there was issues of water getting into the crawl space. Sometimes as much a 6in deep on the low end. I have had several companies look at it and they all want to install a drain system under the structure and install a sump pump. This is not stopping my water from entering. My thoughts were to go to the upper side of the structure about 6 to 10ft from the outside and put in a curtain/french drain that would almost horse shoe that end of the home. I am not sure of the depth to dig this trench to put in my piping. According to the water line in my crawl space it is about 4 or 5 blocks down.That would be roughly 30 to 36 inches. Should my trench on the outside that I am putting 6 to 10 feet from the structure be this deep also or does it have to be this deep. The upper side of the structure where I think the water is coming in at is subsurface and not surface water. The top of the ground stays pretty dry, I think it as stated is subsurface. Do you have any recommendation on location, depth and width for my trench to install a curtain/french type drain?



  30. Mark
    March 21, 2016


    I have rising terrain on one end of my home. Even though I have a positive grade around my home. After a heavy rain I have standing water in my crawl space and I had a local contractor tell me that my drain needed to be below the level of my footer which is deeper than 24". My footer walls are 6 blocks high. Will the 24" deep drain you suggest work or will it have to be the depth the contractor suggested.

  31. Jackie
    April 2, 2016

    Hello my name is Jackie Kramer, I am writing because my basement sump pump is running all the time. My house is a factory build home. It was put in 1995 it has 12-13 block high basement walls. The water table is high i have all sand mainly around. A lot of water come in threw the tile that is in the sump pump tub. I would like to finish my basement but with the water coming in i am scared. I have brought so many sump pumps. I really don't KNOW WHAT TO DO?

  32. Don Sarazen
    June 14, 2016

    I have dug a trench for a French drain to prevent water from entering my basement. It is about 4 ' from my house. It is 6'deep, 3' wide at the top then tapers down to about 1' at the bottom. It is 23'long. I am convinced I need to use rigid PVC pipe instead of black flexible tubing. I noticed in the pictures you have that there is no material used to line the trench before putting in the gravel is there a pipe sleeve used. Are these things not necessary?

  33. Robert perez
    August 25, 2016

    Hey,I'm the guy who put the drainage plastic pipes holes upward to the sky,oh,good grief Charlie Brown,I read and like any good Boy Scout I will email you guys my own testimony,hey,thanks a lot for pulling my harum out of the "ditch"!

  34. Gordon
    January 16, 2017

    Is there a formula to calculate the volume of water that can be expected to reach the bottom of a house footer to then be "carried away" by a French drain after a moderate to heavy rain storm? The block foundation walls are about 8-1/2 feet below ground level to the footers. The soil conditions vary from ~10 inches of top soil, then about 2 feet of clay/shale, the balance to the footer being horizontal layers of hard shale. There's a total of about 90 feet of French drain hose installed around the perimeter of this addition to an existing house. The surface area of the fairly level ground around the addition is ~4,000 square feet. The house is located in the northern Pittsburgh suburbs.

    • Tim Carter
      January 16, 2017

      That formula exists but ONLY where the water is passing unobstructed through pipes or very open gravel with little / no resistance. If you need further help or assistance, I offer over-the-phone consulting. My college degree is in geology with a deep interest in hydrogeology - the study of groundwater. CLICK THIS LINK:

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