Yard and foundation drainage
Understand your French drain quote before you dig.
Drainage estimates are often two lines long for work that will reshape part of your property. 'Install French drain, 80 feet' says nothing about depth, pipe, stone, fall, where the water goes, or what your lawn looks like afterwards.
Upload the estimate you already have and Learn The Quote explains what the scope appears to cover, which specifications are missing, and what to ask before excavation starts.
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Updated September 2026
Drainage Installation Estimate
Illustrative sampleRear yard water pooling near foundation
- Trench length84 LF
- DepthNot stated
- Pipe4" perforated, sock
- StoneWashed gravel
- Discharge'To lower grade'
- RestorationBackfill only
Learn The Quote note
Two blanks to fill before signing: how deep, and precisely where the water comes out.
Example figures only. Real estimates vary widely by region, specification and site conditions.
What should be in the quote
What a clear drainage quote normally covers.
Every contractor writes proposals differently. These are the details homeowners most often want to see spelled out before signing — a missing item is not automatically a problem, but it is usually worth a question.
- Trench route shown on a sketch or plan
- Trench length in linear feet
- Trench depth and width
- Pipe type, diameter and perforation
- Sock or fabric sleeve on the pipe
- Stone type, size and volume
- Filter fabric method
- Fall or slope target toward the outlet
- Cleanouts or inspection ports
- Catch basins or surface inlets
- Downspout tie-ins
- Solid discharge line length
- Discharge point and method
- Pop-up emitter or dry well
- Utility locate responsibility
- Excavation method — machine or hand
- Spoil removal or on-site grading
- Hardscape cutting and replacement
- Turf, topsoil, seed or sod restoration
- Irrigation line repair
- Permit where required
- Workmanship warranty and exclusions
Line-item breakdown
What each line on the estimate actually pays for.
| Line item | What it covers | What moves the number |
|---|---|---|
| Excavation | Digging the trench to the specified depth along the route. | Length, depth, soil type, rock, tree roots and whether a machine can reach the route. |
| Perforated pipe | The collection pipe placed in the trench, usually with a fabric sock. | Diameter, rigid versus flexible, and whether a sock is included. |
| Drainage stone | Washed gravel surrounding the pipe so water can move into it. | Trench volume and how much stone is specified above and below the pipe. |
| Filter fabric | Geotextile separating soil from the stone to slow clogging. | Whether the fabric wraps the trench, the stone or only the pipe. |
| Discharge line | Solid pipe carrying collected water from the trench to the outlet. | Distance to a suitable outlet and available elevation change. |
| Outlet detail | How water leaves the system — daylight, pop-up emitter, dry well or basin. | Site grade, property boundaries and local drainage rules. |
| Catch basins | Surface inlets collecting water that never soaks in. | Number of low spots and whether downspouts tie into the system. |
| Restoration | Backfill, topsoil, seed or sod, and repair of driveways, patios or walkways crossed. | Whether hardscape must be cut, and the finish level expected on turf. |
| Spoil handling | Removing or regrading the soil displaced by the trench. | Trench volume and whether the property can absorb the material. |
A higher price is not evidence of overcharging, and a lower price is not automatically a better deal. Two estimates can differ because they describe genuinely different work.
Commonly missing or unclear
The gaps homeowners notice after work has started.
- Trench depth never stated, so the two quotes you hold are not comparable.
- No sketch or route description, leaving the location open to interpretation.
- Discharge described only as 'to lower grade' with no defined outlet.
- No solid discharge line priced between the trench and the outlet.
- Stone volume unstated, so it is unclear how much surrounds the pipe.
- Filter fabric not mentioned at all.
- No cleanouts, making future maintenance harder.
- Downspouts left disconnected although they feed the wet area.
- Hardscape crossing shown on the route with no cutting or replacement line.
- No turf, topsoil or sod restoration after excavation.
- Irrigation and low-voltage lighting lines not addressed.
- Utility locate responsibility unassigned.
Allowances, exclusions and extras
Where the final invoice can drift from the estimate.
Rock and roots
Unexpected rock, large roots or buried debris can slow excavation and is often priced as extra.
Insufficient grade
If the route lacks fall to a suitable outlet, the solution may change to a basin and pump, which is different work.
Hardscape crossings
Cutting and replacing concrete or pavers adds cost and may not be included in the base price.
Private utilities
Irrigation, lighting, septic and pet-fence lines are often not marked by public locate services.
Turf establishment
Seed needs time and water. Sod costs more but restores appearance immediately. Confirm which is priced.
Downstream effects
Where water is discharged can affect neighbors and may be subject to local rules. Confirm the plan before work starts.
Questions to ask
Ask these before you sign.
- 1Can you mark the trench route and show me where it runs?
- 2How deep and wide is the trench?
- 3What pipe diameter and type, and is it sock-wrapped?
- 4What stone is used, and how much surrounds the pipe?
- 5How is filter fabric installed — around the trench, the stone or the pipe?
- 6How much fall does the run have, and how is it verified?
- 7Exactly where does the water discharge, and how?
- 8Are downspouts being tied in?
- 9Are cleanouts included for future maintenance?
- 10Who locates utilities, including irrigation and lighting?
- 11What restoration is included — backfill, topsoil, seed or sod?
- 12What warranty applies, and what would void it?
Quote red flags
Wording that deserves a second look.
- A scope with no depth, no pipe specification and no outlet described.
- A promise that the yard will 'never hold water again'.
- Discharge onto a neighbor's property with no discussion of local rules.
- Excavation quoted without any utility locate responsibility.
- No restoration line on a trench crossing lawn and beds.
- Large deposit requested before any locate or layout is done.
- Corrugated flexible pipe used with no explanation on a long run.
- No written warranty on a system that will be buried and hard to inspect.
None of these mean a contractor is doing anything wrong. They are simply points where the written document leaves room for interpretation.
Comparing competing estimates
Are the two bids even for the same job?
- Compare trench length and depth before comparing price.
- Check pipe type and diameter on both quotes.
- Compare stone volume and fabric method.
- Confirm both use the same route and the same outlet.
- Check whether the solid discharge line length is included in each.
- Compare catch basins and downspout tie-ins.
- Compare restoration — backfill only versus full turf repair.
- Compare warranty length and stated exclusions.
What affects pricing
Labor rates, material costs, project complexity, geography, permitting, site access, specifications and current market conditions all move the number. There is no single universally correct price for a job, and Learn The Quote does not claim to determine one.
Length and depth
Trench volume drives excavation labor, stone quantity and spoil handling together.
Soil and obstacles
Clay, rock, roots and buried debris all slow digging and can force hand excavation.
Access
Whether a machine can reach the route, or the work must be done by hand, changes labor dramatically.
Outlet distance
A long solid discharge run to a viable outlet adds pipe, trench and restoration.
Hardscape
Cutting and replacing driveways, walkways or patios adds concrete or paver work.
Restoration level
Seed, sod, plant replacement and irrigation repair vary widely in cost.
Comparing two proposals for the same job? Read our guide to comparing contractor quotes before assuming the cheaper one is the better value.
How Learn The Quote helps
An independent read of the document you already have.
Upload your quote
Upload the written drainage estimate you already received. Your first Quote Snapshot is free.
We read it closely
We organize the proposal in plain English and flag items that look unclear or potentially missing.
You ask better questions
You get price context and specific questions to put to your contractor before you sign.
Learn The Quote is informational and document-based. We do not issue price verdicts, we cannot tell you a universally correct price, and this is not a substitute for licensed trade, engineering, legal or financial advice or for an onsite inspection. We are not a contractor marketplace and we do not sell your details.
Why lowest is not comparable
Why the cheapest drainage quote may be a different system.
Drainage is the trade where identical-sounding scopes diverge most. A 90-foot trench at 24 inches with washed stone, wrapped fabric, a sock-wrapped rigid pipe and a 40-foot solid line to a defined outlet is a substantially larger job than a 60-foot trench at 12 inches discharging 'to lower grade'.
Because everything ends up buried, the difference is invisible on completion day. It shows up the next time a heavy storm arrives, or years later when fine soil has migrated into unwrapped stone.
We do not judge whether a price is fair. We read what each document specifies, so you can see whether two quotes describe the same system before you decide on price.
What we look for
What Learn The Quote checks on a drainage estimate.
- Trench route, length, depth and width, and whether a sketch exists.
- Pipe type, diameter, perforation and sock.
- Stone specification and volume, and the filter fabric method.
- Stated fall and how it is verified along the run.
- Outlet location and method, and the solid discharge line length.
- Catch basins, cleanouts and downspout tie-ins.
- Utility locate responsibility, including private lines.
- Restoration of turf, beds, irrigation and any hardscape crossed.
Questions homeowners ask
Frequently asked questions
- What should a French drain quote specify?
- At minimum: trench length and depth, pipe type and diameter, whether the pipe is perforated and sock-wrapped, the stone size and volume, whether filter fabric is used, the amount of fall, where the water discharges, and how the surface is restored afterwards.
- Why does the discharge point matter so much?
- A drain only works if water has somewhere lower to go. Estimates sometimes describe collection in detail and leave the outlet vague. Ask exactly where the pipe daylights, how far away it is, whether a pop-up emitter or dry well is used, and what happens if there is not enough grade.
- What is the difference between a surface drain and a French drain?
- A surface drain collects water at grade through grates and catch basins. A French drain is a gravel-backfilled trench with perforated pipe that collects water moving through the soil. Many yards need both, and a quote that mixes the terms should be clarified.
- How much fall does the pipe need?
- Drain lines need continuous slope toward the outlet. Contractors commonly target a small consistent fall over the run, which is why total length and elevation change matter more than the ditch looks like it should. If the quote does not mention fall, ask how it is being achieved and verified.
- Is filter fabric necessary?
- Fabric is normally used to keep fine soil from migrating into the stone and clogging the drain. Approaches differ on whether fabric wraps the trench, the stone, or the pipe. It is worth knowing which method is priced, since it affects both cost and service life.
- Will an interior or exterior drain be better for my basement?
- That depends on how water is entering, and it is a site-specific judgment for a qualified contractor or engineer — not something a document review can determine. What we can tell you is whether the quote you hold describes its approach clearly enough to compare with another.
- What restoration should the quote cover?
- Excavation disturbs turf, beds, irrigation, driveways, patios and sometimes fences. Look for lines covering spoil removal, backfill, topsoil, seed or sod, and repair of any hardscape crossed by the trench. Restoration is one of the most common omissions.
- Why do two French drain quotes differ so widely?
- Usually trench length, depth, stone volume, whether excavation is by machine or hand, whether hardscape must be cut and replaced, and how far the discharge line runs. The cheapest total often prices a shorter, shallower trench with less restoration.
- Should utilities be located first?
- Excavation near buried gas, electric, irrigation and septic lines requires a utility locate. Ask whether locating is included and who is responsible for private lines, which public locate services typically do not mark.
- How does Learn The Quote help with a drainage quote?
- Upload the written estimate and the free Quote Snapshot summarizes what it appears to include and how many points look unclear. The $39 report walks the full scope in plain English with a question list. The $59 Compare service reads two drainage quotes side by side.
Helpful homeowner resources
More reading before you sign.
- Basement waterproofing quotesInterior and exterior systems, sumps and warranty wording.
- Foundation repair proposalsScope wording, pier counts and the engineer's role.
- Driveway quote reviewBase preparation, drainage and joint layout.
- Retaining wall quote reviewDrainage behind the wall is most of what you pay for.
- Gutter quote reviewWhere roof water goes before it reaches the ground.
- Questions before signingScope, exclusions, payments and warranty wording.
Learn The Quote is an independent, document-based quote-review service. We are not a contractor, engineer, geotechnical consultant or home inspector, we do not inspect properties or diagnose the cause of water intrusion, and nothing here is engineering, drainage-design or legal advice. Discharging water can be subject to local regulation and can affect neighboring property — confirm requirements locally. We do not determine whether any contractor's price is objectively fair and we do not promise savings.
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