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Question DetailsAsked on 12/9/2013

how much external drainage cost

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6 Answers

Voted Best Answer

Wow - from way general to totally specific - nice job, you have your scope of work almost ready to contact potential bidders about giving a bid - just need to double check each item hads quantities attached to it, plus a plan with depths (or specify tie-in elevations to existing pipe and required drain/pipe slopes - say 1% or more). Search the List (in green banner bar) for Earthwork and Excavation contractors in your area with good reviews and ratings.

here is a very rough idea of costs - obviously you need bids to tie it down, this should just give you a ballpark to compare to - assuming all this work is done at the same time.

1) & 2) - Tree and rock maybe $100 - more like $200 if you want the stump totally rooted out rather than just the stump and root crown taken out.

3) Walk removal and disposal probably about $100-200 - maybe half if these are 3-4 inch individual concrete squares or rectangles that can be skidded to the side, the excavation and ground sloping done, then slid back into place with a backhoe or bobcat or by wood skids and prybar, eliminating the hauling and disposal cost.

4) Excavation and disposal of soil probably about $20-30/CY, because you are talking a small quantity. Cheaper if you have an on-site area it can be spread out onsite for disposal, or stockpiled in yard as a future project dirt pile, if that is suitable.

5) You don't say what the existing drain is - underground drain for downspouts maybe ? For shallow burial, probably about $5/LF or so. Why square - round is cheaper and far stronger for given material thickness.

6) Fence R&R probably about $150-200, depending on depth of posts and whether concreted in or not.

7) vegetation removal - not knowing how much, $100-200

8) Garden wall around $10-12/SF assuming excavated material from yard is suitable for the general backfill - remember should go 4-12 inches below grade for stability (4" for this wall, more like 6-12 for higher front wall)

Front/side yard:

1) Move large boulder - $50-100

2) vegetation removal and relocate 3 shrubs - $150-300 (not knowing how much vegetation orhow big shrubs are)

3) excavation at $20-30/CY again as above

4) sprinkler system relocate/repair - $75-150

5) garden wall around $12-15/SF as above including concrete footer needed for this height wall

6) area drain laterals about $5-10/LF, assuming not over 3 feet deep

7) slab drainage - I don't know where the quick lime idea came from, but this is a no-go - it will remove a small amount of water (maybe 5-20 gallons) from the soil one-time - it has no long term function as it will quickly become saturated. You are actually likely to have 5 wet circles in your concrete slab from this forever, as the lime will act as a soggy sponge, retaining water that would otherwise wick away. If you have or expect a basement slab moisture problem, then you need a sump pump with sump installed, and possibly (depending on how free-draining the base material under your slab is to carry waer to the sump pump) lateral drains cut in below the perimeter of the slab. Can run from $800-1500 range for a pump and pit depending on capacity and wiring situation, plus $500-1000 for an emergency battery-powered backup if desired. $1000-2500 range typically if lateral drains around the perimeter of the slab are necessary. Cheaper but sloppier and moisture-causing solution is small trenches or above-slab channels to carry the water to sump pump. These laterals are commonly held off on till you see if the sump pump can handle the issue itself, ASSUMING you have unfinished basement so a bit of seepage aroundbthe slab does no more damage than needing a mopping up. Personally, unless you have a continual seepage of water into basement or it is finished so leakage is critical, I would leave sump pump and drains for later - to see if your surface drainage changes eliminates the basement dampness problem, which it commonly does unless your water table rises to the basement slab level. Also, having a sump pump implies water issues and tolls against any future buyer finishing an unfinished basement, so it detracts from resale value if you have one.

Note these are off-the-cuff type numbers, NOT any sort of deliberate estimate - but I felt it was better to give you a ballpark than to just say go get estimates. Except for the floor drains, this sounds like a good job for a small 1-3 man excavation and hauling company, but make sure they have experience in putting in drain pipe and block walls and have good references in that area.

Note- if you are inclined to do it yourself work and have the time, most of this is good homeowner home improvement project material. You could have a contractor with a bobcat or small tractor with small backhoe come and pull the fence posts out (you could remove the above-ground apart easily), trench for the pipes, maybe move the rocks and sidewalk (though you could do that yourself with a few scraps of wood as skids and a 5 foot prybar assuming the walk is in piece, not continuously reinforced, and to do the bulk excavation and hauling for you, leaving the vegetation clearing, pipe work, trench backfilling, final slope dressing, block wall building, transplanting, etc to you - could cut your cost about 1/3-1/2. Basement slab drainage I consider a separate issue which would not cost significantly different if done as part of this job, or later if drainage channels or slab french drains are deemed necessary.

For the excavation - remember to get utility locates - I recommend once for bidding so they know where utilities are, then require the bidder to get relocates just before excavation starts. Gas, telephone, cable TV are commonly less than a foot down - water and sewer usually 3 feet or more but don't count on it. Also worry about septic system is you have that, and any power or water lines to/from well if you have a well. Plus of course your sprinkler system if in the way of proposed excavation.

Good Luck with your project

Answered 5 years ago by LCD


Too wide open a question - I could say $10-25 for you to put an extension on a downspout to direct water away from the house to $20-50,000 range for full basement slab removal and drain installation combined with exterior foundation wall excavation with waterproofing and french drain and wet well installation, to $1 million+ range for a full levee protecting your house 360 degrees from river flooding.

As you can see, depends on house and property configuration, what the source of the problem is, how much of a problem you have and if seasonal or year-round, etc.

If you go to the Browse Projects area at lower left, then expand out the Home category and click on Basement Waterproofing, you will find a slew of comments on the causes and easy fixes for water intrusion proboems, as well as ballpark costs for different types of solutions, and discussions of which solutions are typically appropriate or economical for certain types of issues.

If after reviewing some of the prior comments in Basement Waterproofing, you use the Answer the Question button to provide more detail of your situation, perhaps we can give a more specific and directly applicable answer.

Answered 5 years ago by LCD


here is the work that needs to be done, can you please give me an answer roughly?

Surface Grade around Sunken Living Room Remedial Repair: (75 Sq. Ft.)

Right Side:

1. Remove 2 foot Dia. tree stump.

2. Remove and relocated existing 2 foot Dia. granite boulder.

3. Remove 2’ wide x 15’ long concrete walk that is to high and draining to the house at interior slab elevation.

4. Excavate 5’ wide by 15’ long of soils to create grade to code. Approx. 4.2 Cu. Yds. of soil removal.

5. Replace existing drains with one 12 inch square drain. Note: existing pipe may be to high in elevation and may require a new pipe installation. The existing pipe may be thin walled corrugated pipe. It is the pipe may be filled with roots and clogged. This pipe replacement if required would be an extra in addition to our contract price.

6. Remove and replace 5’ long by 5’ tall wood fence for access to work area. Replace with two new posts when work is completed.

7. Remove all vegetation in work area and take to the dump.

8. Install at property line a new 2’ tall by 15’ long Keystone garden wall to prevent soil erosion of neighbors lot onto this property.

9. Others to re-establish irrigation and landscape.

Front and partial side to fence grade remedial repair: Front (140 Sq. Ft.)

1. Relocate 3.5’ x 2.5’ x 2’ granite boulder next to house to new location. Boulder is Approx. 1,000 pounds or more.

2. Excavate and remove from site all plants and vegetation. Transplant 3 existing shrubs at new grade.

3. Excavate 13 Cu. Yds. of soil from area in front house. Export 19 Cu. Yds. to legal dump site.

4. Move 3 existing leaking irrigation valves and replace with new ones approximately 10 feet from house.

5. Install 31’ long by 2.5 to 3.5 tall Keystone garden wall along front walk, across to property line and tie into side wall.

6. Install 2 new 6” Dia. area drains to existing pipe.

7. Connect two existing down spouts to existing pipe.

Quick Dry interior concrete slab:

1. Drill 5 - 6” Dia. cores through interior slab.

2. Earth auger out 6” Dia. by 3’ deep of soils.

3. Fill with Quick Lime to dry soils and slab.

4. Patch holes in slab with 5,000 PSI, non-shrink grout.

Answered 5 years ago by SeaMan


Thanks for this detailed answer!!

This is a great service, keep it up guys.

Actually this is not my estimation and work order.

Although I’m a handyman, I would prefer to hire someone to do it.

This is a consulting and work order made by one bidder, the one i laid out here.

I'm trying to get a second opinion and educate myself about this process, also find other bidders (hopefully from this site) to do the job.

For the quick lime thing, this is a living room that the initial inspector said that it has moisture, well I still think it is subjective.

the wood/nails that the carpet fits on are rusty in one corner of the room close to the missing drainage spot, and he said of the lack of the drainage outside the room which is outside the house surrounding this room, one side of the room is done with 2 drainage system (and this bidder wants to redo it) and the other side of the room needs 2 more drainage system with pipes, all other shrubs and stones are in the way.

He is saying that cuts the bleeding by adding more drainage and grading the ground 5 feet away from the wall (the room wall, that is the outside wall)

Then putting the lime in the sunken living room will evaporate the moist.

Now as I said this house is 28 yrs old, and if the moist is that bad, the case should have been a lot worse.

I can send you the inspector report with pic (pdf file) if that helps to look at the problem more.

Thanks a lot.

Answered 5 years ago by SeaMan



What category I should look for to find bidders in this site? I would like to have 1-2 bids on this job.

Answered 5 years ago by SeaMan


Hi, this is Meranda with Angie's List. You should be able to find someone to help with your project by searching at in the category "drain pipe installation - exterior" or perhaps "excavating."

If you have trouble or other questions, you can contact our Member Services department to help search at 1-888-944-5478 between Mon-Fri: 8:30am – 8:15pm and 
Sat: 8:30am – 3:00pm ET

I hope that helps!

Answered 5 years ago by Meranda


Okay - more info, more details, so now I understand the situation better. Some reference material below for you to peruse:

Here is an Angie's List article on the general waterproofing/drainage issue, plus another article on interior versus exterior drains, in case you do not understand the waterproofing issue fully -

Here is one on exterior drainage and basement waterproofing -

and here is an article on drainage control costs -


Now - back to your specific issue - I am still not clear if this is an at-grade or shallow slab where the dampness is/was, or if you are talking a full or daylight basement.

If at grade or only a foot below or so, then getting the roof and rain runoff away from the house by sloping the soil away, including a highly compacted clayey soil layer or heavy duty (HDPE or similar) plastic liner sloping at a 5% slope or better away from the house (which can be below a shallow topsoiled flower bed or plantings) will normally take care of the issue unless you have a very high water table. For a daylight (half-buried) or full basement, adequate control of runoff and rainfall goes a long ways, but if the groundwater level rises during wet periods due to rising water in nearby drainages or highly pervious soil, then another approach is called for. As the articles say, you can do exterior french drain pipes along the footer (which typically run about $10/LF for ones only a foot or two deep, to more like $30-40/LF for ones 4-6 feet deep) IF you have a free drainage surface to drain to. Obviously, if the surface water level rises to the level of the drain pipes at the outlet, then they stop draining and just sit immersed in water till the water level goes back down. If this is the case, then you need to consider waterproofing the outside of your foundation wall to restrict water flow through cracks and joints there, then ALSO install interior drainage - generally at least a sump pump, and if your slab was not built on top of a good free-draining gravel bedding, then interior lateral drains around the perimeter as well feeding to the sump pump.

If you have to go with deep perimeter french drains around the outside of the house, you have a tough decision to make - whether to excavate all around the foundation and have the full foundation surface sealed with bitumastic or plastic liner at the same time. Difference in cost is about $30-40/LF for a trenched drain pipe only, to more like $70-110/LF for full excavation along the wall down to the footing, clean the wall, and waterproof it and put in the french drain.

For situations where the surface water level rises above the footing level or is always high, you are pretty well stuck in most cases with exterior waterproofing AND interior sump pump/drain system, because it is rare you have this situation and still can have a french drain that drains freely to an open surface above water level - a necessity for a french drain to serve its purpose. Generally, high water table at your house means flat or low-lying conditions around the house, so adjacent drainages typically have water in them at the same elevation and there is no lower lying place for the french drain to drain to. Occasionally one will put in a wet well (a large sump) to collect the exterior french drain infiltration and pump it out to a surface drainage but this is more expensive, and of course like with a sump pumps it counts on having power when you need it and the pump not failing when it is most needed. Therefore, in this situation most people do exterior waterproofing to cutoff inflow through the walls, typically with a highly compacted zone beside and slightly below the footing to limit flow under the footing, then an interior sump pump and maybe interior french drains to intercept the water that does make it under the foundation and through the subsoil or is coming up under the basement slab, and pump it out to surface runoff away from the house.

On your specific issue - the rusty nails could indicate some slight water infiltration in the past or even spillage from somethign like a dehumidifier, but if the concrete slab does not show rusty water staining and lime leaching (white stains) away from that point, it could have just been a one-time event or very minor moisture seepage if there is no mold there indicating current wetness. If there is a chance that surface water backed up against the house at that point and you do not have generally high water table, it may well be that reworking the outside surface drainage will solve any problem. Hard to tell - because come to think of it you did not say why you are considering this project in the first place - what got you started on drainage as an issue around your house.

It is a WHOLE lot cheaper to do some excavation and compaction around the foundation and put in a highly water resistant layer (highly compacted soil if clayey, or adding a compacted clay layer or putting in a 3-6 foot wide impervious membrane sloping from ground surface at the house away from the house), than to put in a drainage pipe that may not be needed. In many cases, the problem is caused by the settlement and high permeability of the (commonly) uncompacted soil right along the foundation, and can be solved by regrading for 3-5 feet from the house to drain away, and just compacting that first 3 feet or so so it actually sheds water rather than acting as a sump to rainwater. And of course, watering plants deeply or leaving soaker hoses running for significant periods of time within 3 feet of the foundation commonly aggravates the issue.

Personally, assuming you have no other water infiltration evidence or mold problem, if this is an at grade or only slightly below grade slab I would do the regrading only using an excavation andf hauyling contractor, keeping the outside surface below the top of the slab level if possible, with no new drain pipe, to see if that takes care of the issue. You can always do drainage or waterproofing later if needed, but jumping into several thousands of $ of drainage or waterproofing when it may not be needed seems a waste.

Couple of closing thoughts:

1) concentrated flows like downspouts need to drain at least 3 feet away from the foundation on even tight, impermeable soils - and more like 6-10 feet away in gravels or sands, to prevent the water from seeping back to your foundation. Commonly this involves putting in a plastic liner in a small ditch, or digging in an open piece of plastic gutter as a drain trench.

2) capture roof runoff with gutters to prevent it dripping off teh roof right next to the foundation

3) if you do go with exterior french drains, make sure that there is an impervious cutoff from the foundation wall, under the drain, and out to the outward side of the ditch. SO many contractors totally blow it by digging down to or next to the footer, or even a bit below it, thinking they are doing better by going to the base of the footer to capture the water. That is fine, but if you do not put an impervious bitumastic or heavy duty plastic liner nailed with firring strip and sealed to the foundation wall, down over the footer alongside the drain gravel, then horizontally across under the drain, all you have done is installed a highly pervious gravel water sump right at the base of your foundation, which will allow much more water into the basement, I have consulted on jobs where a minor weepage issue in a basement became a steady flow at the basement slab crack after an exterior drain was put in, because a direct path under the footer was created. Remember also that not only the pipe but also the gravel bedding need to slope to free drainage, because otehrwise the gravel bedding just acts as a big saturated sponge, keeping water against the foundation. Many articles also show the pipe bedded fully in 6 inches or so of gravel - actually, the pipe should be bedded in just enough bedding to prevent damage to the pipe, then filter fabric to prevent the bedding from getting into the pipe. That keeps the drain holes in the pipe low, so there is as little water buildup under the pipe as possible.

4) any drain pipes should have curved access from cleanout for each straight run - street 90's or curved wyes are suitable for this, with a capped standpipe to ground surface. Many contractors do not put in cleanouts at the uphill end, or use tight 90's that a drain cleaner cannnot get through.

5) do NOT allow anyone to convince you to drill holes through the foundation to the outside to bring outside water into the basement to be collected by an interior drain system. It just makes absolutely no sense to increase the flow into your basement - you are then putting all your trust in the sump pump ALWAYS working perfectly. A number of people have installed interior trough systems that recommend doing this, then during a major storm, hurricane, etc just when the inflow is greatest due to heavy rains, a storm caused power outage takes out their sump pump and they have rapid basement flooding, instead of just a trickle that can be handled with buckets if necessary, or takes hours to build up to damaging levels if the owner is not at home.

Good luck with your project.

Answered 5 years ago by LCD

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