A gravel trench
We dig a trench along the path of the water and fill it with gravel, giving the water an easy route to flow into instead of pooling.
Bay Area French Drain Installation · Licensed · 13+ Years
French Drain Installation in the San Francisco Bay Area
Water that collects against your foundation is what cracks it, floods your crawl space, and breeds mold. A french drain intercepts that water and carries it safely away — before it does the damage.
Free inspectionLicensed (CSLB #1022608)Foundation & crawl-space drainage13+ years experience
Free on-site estimate · No pressure · We come to you
Why It Matters
Move Water Away Before
It Reaches Your Foundation
The Bay Area's wet winters and clay-heavy soil hold water — and clay doesn't drain well, so that water pools against foundations and seeps into crawl spaces and basements. Once it's there, it's relentless: it works into foundation cracks, floods the space under your home, and feeds the moisture that leads to mold, wood rot, and pests.
A french drain is a simple, proven fix: a gravel-filled trench with a perforated pipe that collects the water and channels it to a safe outlet, well away from the house. It's often paired with a sump pump to pump the water out where gravity can't, and it's the first step to drying out a crawl space that keeps taking on water.
- Keeps water away from your foundation
- Stops crawl space and basement flooding
- Prevents pooling in the yard and against the house
- Protects against cracks, rot, and mold
- Reduces damp, musty air in the home
- Pairs with a sump pump for full drainage
How It Works
How a French Drain
Protects Your Home
It's a straightforward system — but where it goes and how it's built determine whether it actually keeps you dry.
A perforated pipe
A perforated pipe set in the gravel collects the water that filters in and carries it away from the foundation.
Filter fabric
Fabric wraps the system to keep soil and silt from clogging the pipe, so the drain keeps flowing for the long term.
A safe discharge point
The pipe routes the water to a safe outlet — daylight, a drain, or a sump pit — well away from the house where it can't seep back.
Interior or exterior
We install exterior drains to intercept water in the yard, or interior perimeter drains inside a crawl space or basement — whichever fits.
Works with a sump pump
Where the water can't drain by gravity, the drain feeds a sump pit and the pump lifts it out — a complete drainage system.
Do You Need One?
Signs Your Home
Needs a French Drain
Drainage problems show up as water where it shouldn't be — and as damage that follows. Watch for these.
Water pooling near the house
Puddles that linger against the foundation or in low spots of the yard after rain mean water isn't draining away as it should.
A wet or flooded crawl space
Standing water or persistent dampness under the house is a clear sign you need to intercept and redirect that water.
Foundation cracks or settling
Water working against the foundation causes cracks and settling over time — a drainage issue worth addressing early.
Damp, musty odors
A musty smell rising into the house usually means moisture is collecting under or beside it and feeding mold.
Water stains on foundation walls
Stains or white mineral crust on basement or foundation walls show water has been coming through.
Soggy ground after every rain
Ground that stays saturated long after a storm — especially on a slope draining toward the house — calls for a drain.
How We Work
Our French Drain Installation Process
A french drain only works if it's placed where the water actually goes — which is why we start with an inspection, not a shovel.
Free inspection
We inspect your property, crawl space, and grading to trace where the water comes from and how it flows, so the drain goes exactly where it's needed.
Plan the route & outlet
We plan the trench path and a safe discharge point — to daylight, a drain, or a sump pit — that carries the water well away from the house.
Dig & lay the drain
We dig the trench to the right depth and slope, wrap it in filter fabric, and set gravel and a perforated pipe for reliable flow.
Connect drainage if needed
Where gravity won't do it, we tie the drain into a sump pump so the collected water is pumped out and away.
Backfill, test & clean up
We backfill, confirm the water flows to the outlet as intended, and leave the site clean.
Free inspectionLicensed (CSLB #1022608)Drainage traced & done right
Why Attic Pros
The Bay Area's Trusted
Drainage & Waterproofing Team
For over 13 years, Bay Area homeowners and businesses have trusted us to solve their water problems — because we trace the water to its source, install the drainage that actually fixes it, and stand behind the work.
- Licensed contractor (CSLB Lic. #1022608)
- SPCB-registered for pest-related work (Co. Reg. #9901)
- Diamond Certified & Angi Super Service Award winner
- Independently reviewed — verified Google ratings
- Free, no-obligation on-site inspection
- Local team with 13+ years under Bay Area homes
Real Customers, Real Results
Trusted by Bay Area Homeowners
4.8
★★★★★
Based on 1,900+ verified Google reviews — trusted for drainage, waterproofing & home services across the Bay Area
Google Review
★★★★★
Tom from Attic Pros was great to work with! He was friendly, professional, and thorough during the inspection. He clearly explained everything he found and answered all of my questions. The whole process was straightforward. Thank you, Tom!
Daria Baevski
Google Review
★★★★★
Finding out we had a rodent infestation for the first time was incredibly stressful, but Attic Pros made the entire process so much easier! Jeremy was very knowledgeable when help preparing the estimate and the work that needed to be done. Their team that came to perform the work—Nico Otten, Juan Rodriguez, and Antonio Lopez—were amazing from start to finish. Communication was fantastic right from the beginning. The crew was super fast, highly efficient, and left everything very clean after sanitizing our attic, crawl space, and garage. They definitely gave us total peace of mind. They were also able to finish in one day!!
Annie M
Google Review
★★★★★
Our small cottage has a very narrow attic entrance. Denis from Attic Pros was willing to try and was able to enter to clean, vacuum, and replace the old insulation. Very professional, access areas were well shielded and protected. Powerful vacuum and clean up well after themselves.
Morgan Yang
Google Review
★★★★★
Tom Best came to our house to give us an estimate on new insulation. He was on time, very thorough and provided a detailed very reasonable estimate within an hour of his visit. What more could you want?
B Kellar
Google Review
★★★★★
Samim great service my attic was left very clean meticulous. I am so happy with the work that him and his team did great service. I recommend them highly. I would give them a 10 if I could.
Darlene Galindo
Google Review
★★★★★
David from Attic Pros was professional, knowledgeable, and thorough. He clearly explained the extent of our rodent problem in the attic and showed us detailed photos and videos so we could fully understand the damage. He took the time to explain exactly what the rodents had caused and walked us through how the repairs would be completed. David was friendly, patient, and easy to talk to, making the entire process much less stressful. We really appreciated his honesty and professionalism.
Carmen Plascencia
QUESTIONS, ANSWERED
Frequently Asked Questions
Straight answers to the questions people actually ask about french drains — what they are, interior vs. exterior, and how they work with a sump pump. Still unsure? Our team is happy to help.
Still have questions?
Talk to our team — we're here to help.
(800) 543-0382It's a gravel-filled trench with a perforated pipe running through it. Water flows into the gravel, filters into the pipe, and the pipe carries it to a safe outlet away from your home. It's one of the most proven ways to redirect groundwater and surface water so it stops collecting against your foundation.
It depends on where the water is and how it's getting in. An exterior drain intercepts water in the yard before it reaches the house; an interior perimeter drain runs inside a crawl space or basement to catch water that's already coming through and route it to a sump. We determine the right one during the inspection.
Yes — they're a natural pair. The french drain collects and channels the water, and where it can't flow away by gravity, it feeds a sump pit and the pump lifts it out. For homes with a real water problem, the two together make a complete drainage system.
In most cases, yes — if water intrusion is the cause. By intercepting the water and carrying it away, a french drain stops the source of the dampness. When the space has already been damaged, it's often paired with crawl space cleaning and insulation removal to restore it.
Depth and placement depend on where the water flows and the layout of your property — that's exactly what we map during the inspection. The goal is to set the trench along the water's path at the right depth and slope so it drains reliably to a safe outlet.
A properly installed french drain — with filter fabric to keep silt out and the right slope — lasts for many years. The main enemies are clogging and poor drainage design, both of which come down to how it's built, which is why the installation matters.
It depends on the length of the run, access, and whether a sump pump is tied in. Many residential french drains are completed in a single visit or two. We'll give you a clear timeline with your estimate after the inspection.
Very little when it's built right. Keeping the discharge outlet clear and making sure surface water and downspouts aren't overwhelming it is about all it needs. We'll point out anything specific to your setup at the walkthrough.
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French Drain Installation Across the Bay Area
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Ready when you are
Book Your Free Drainage Inspection
Tell us where you're seeing water — pooling, a wet crawl space, damp walls — and we'll trace it, recommend the right french drain, and give you a clear, no-pressure estimate.