French Drain Installation in Los Angeles: Cost & Hiring Guide
French drain installation comes up most often for Los Angeles homeowners on hillside lots in places like Eagle Rock, Mount Washington, and the Verdugo foothills, where uphill runoff heads straight for the foundation during winter storms. Here's how these systems work, what they cost per linear foot, and how to hire a contractor who understands hillside drainage.
By Jason Green · Crawl Space · Published August 31, 2026 · 8 min read
Why French drains are common in LA
Los Angeles's hillside neighborhoods — Eagle Rock, Mount Washington, parts of Silver Lake, and the Verdugo foothills near Highland Park — sit on slopes where uphill runoff naturally concentrates as it moves downhill, and without a proper drainage system that water heads straight for whatever foundation happens to be in its path.
French drains are the standard fix: a perforated pipe set in a gravel-filled trench that intercepts water before it reaches the foundation and redirects it to a safe discharge point, and they're relatively low-search-volume compared to encapsulation or sump pump work in LA mostly because many homes here don't have drainage problems severe enough to need one — until a bad winter reveals otherwise.
Where French drains make the most sense
A curtain drain installed uphill of a foundation is the classic application, intercepting surface and shallow subsurface water before it reaches the house, and it's especially relevant for properties in Mount Washington, Eagle Rock, and other hillside pockets where the lot itself slopes toward the structure.
A perimeter French drain around the foundation is a second common configuration, often installed alongside crawl space encapsulation to keep the vapor barrier from sitting in standing water after a storm, and this is common in flatter neighborhoods like Mar Vista or West Adams where the soil doesn't drain well due to clay content.
What's involved in installation
Installation starts with excavating a trench at the correct depth and slope (typically at least a 1% grade toward the discharge point), lining it with landscape fabric to prevent silt intrusion, adding a bed of gravel, laying perforated pipe, backfilling with more gravel, and capping with fabric and soil or decorative rock.
The discharge point matters as much as the trench itself — water needs to go somewhere that won't just create a new problem, whether that's a dry well, a connection to an existing storm drain (where permitted), or daylighting at a point well downhill and away from any structure.
Permits and jurisdiction
French drain installation on its own is sometimes considered minor grading work that doesn't require a permit, but if it involves connecting to the public storm drain system, significant excavation near a foundation, or is bundled with other structural work, LADBS (201 N. Figueroa St., Los Angeles, CA 90012) may require a permit for properties within city limits, while LA County Public Works Building and Safety handles unincorporated areas.
It's worth asking your contractor directly whether your specific project needs a permit rather than assuming it doesn't, since discharge onto a neighboring property or public right-of-way without proper routing can create a legal dispute even if no permit was technically required for the trench itself.
Hiring the right contractor
Confirm CSLB license status through the board's free lookup tool, and ask specifically about hillside drainage experience if your property is in Eagle Rock, Mount Washington, or a similar sloped neighborhood, since drainage design on a slope is different from a flat-lot perimeter drain.
Ask what pipe material they use (rigid PVC generally outperforms flexible corrugated pipe over the long run since it resists crushing and silting), what slope they're engineering for, and where exactly the water will discharge.
French drains versus other drainage fixes
A French drain addresses water that's moving toward your foundation from the surface or shallow subsurface; if water is already inside your crawl space or coming from a rising water table, you likely need a sump pump system in addition to or instead of a French drain.
Regrading around the foundation and extending downspouts are cheaper first steps that sometimes resolve minor drainage issues without a French drain at all, so ask a contractor whether your situation actually needs the full trench-and-pipe system or a simpler fix first.
What it costs
French drain installation in the LA metro typically runs $45 to $95 per linear foot depending on trench depth, pipe material, and discharge routing, so a typical 50 to 100 linear foot residential drain project often lands between $2,500 and $9,500 total.
It's also worth having the contractor walk the property with you before digging starts to point out exactly where water currently pools or flows during rain, since that on-the-ground observation, combined with the lot's actual slope, should drive trench placement more than a generic template design that doesn't account for your specific yard's runoff pattern.
Talk to a vetted LA pro
You can find more Los Angeles-specific pricing, permit, and licensing details on Homeowner Henry's Los Angeles crawl space hub page at https://homeownerhenry.com/crawl-space/california/los-angeles, which covers cost ranges, seasonal timing, and vetted local contractor guidance in more depth.
Get matched with vetted Los Angeles pros
Rather than spending hours calling around, you can tell Homeowner Henry what's going on with your crawl space, sump pump, or drainage system and get matched with up to three vetted local contractors who are already familiar with LA's raised-foundation housing stock, seismic retrofit requirements, and hillside drainage challenges.
The matching service is free, there's no obligation to hire anyone, and it saves you the step of vetting CSLB license status and insurance yourself since that screening happens before a pro is ever presented to you.
Typical cost ranges
| Drainage inspection & grading assessment | $250 – $550 |
| French drain (per linear foot, standard depth) | $45 – $95 |
| Curtain drain, hillside install (per linear foot) | $60 – $110 |
| Dry well discharge point | $1,200 – $3,000 |
| Typical 50-100 ft residential project | $2,500 – $9,500 |
| French drain + sump pump combo | $3,500 – $8,500 |
Ranges are general estimates gathered from homeowner-reported quotes, not an offer or a quote for your project.
Common questions
How much does a French drain cost in Los Angeles?
French drain installation typically runs $45 to $95 per linear foot, with a full residential project often totaling $2,500 to $9,500 depending on length and discharge routing.
Do I need a permit for a French drain in LA?
Not always, but if it involves connecting to a public storm drain or is bundled with structural work, LADBS or LA County Public Works Building and Safety may require a permit.
Which LA neighborhoods need French drains most often?
Hillside areas like Eagle Rock, Mount Washington, and the Verdugo foothills near Highland Park see the most French drain installations due to uphill runoff.
What's the difference between a French drain and a curtain drain?
A curtain drain is installed uphill of a structure to intercept water before it arrives, while a perimeter French drain surrounds the foundation itself; hillside lots often need the former.
Should I get a French drain or a sump pump?
A French drain redirects surface and shallow subsurface water before it reaches your foundation; if water is already inside your crawl space, a sump pump is usually also needed.
What pipe material is best for a French drain?
Rigid PVC generally outperforms flexible corrugated pipe over the long term since it resists crushing and silt buildup.
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