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DRAINAGE · WINTER-READY · HILLSIDE

Give the water somewhere to go.

Every atmospheric-river winter, the same SF garages flood, the same crawl spaces go swampy, and the same retaining walls start leaning — because the water was never given a path. French drains, area drains, and sub-surface systems are that path, and building them is concrete-adjacent work we do year-round.

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SCOPE OF WORK

Drainage systems we build

The design question is always the same: where does the water come from, and where is it legally allowed to end up?

SUB-SURFACE

French drains

Trenched, fabric-lined gravel drains with perforated pipe, placed where the water actually travels — along uphill property lines, behind walls, at the base of slopes — and routed to an approved discharge.

SURFACE

Area & channel drains

Catch basins in ponding low spots and channel drains across driveway and garage thresholds — the difference between a wet street and a wet garage.

STRUCTURAL

Wall & foundation drainage

Drainage as part of retaining wall and foundation scopes: back-of-wall systems, footing drains, and sub-slab drainage for dig-downs. Built in, not bolted on.

SITE CONDITIONS · WHERE SF WATER GOES

SF drainage has one weird rule

San Francisco runs on a combined sewer — storm runoff and sewage share the same system. Where your drain is allowed to discharge is a design constraint, not an afterthought.

≈ Storms come in trains now

Recent SF winters have stacked atmospheric rivers back to back — soil saturates in the first storm, and every storm after that runs off like the ground is pavement. Systems sized for an average rain fail in week two of a wet January.

We size for the stacked-storm winter, with cleanouts so the system can be maintained instead of replaced.

§ Discharge is regulated

You can’t aim collected water at your downhill neighbor, and connections to the city system have rules. Legal discharge — to an approved point, with the right air gaps or backwater protection — is part of the design we quote.

On flat west-side lots without gravity fall, that can mean a sump and pump; we’ll tell you upfront rather than trench first and discover it.

△ Drainage saves the expensive stuff

Most of the failed retaining walls and settled foundations we’re called to repair are drainage failures wearing a concrete costume. A drainage system costs a fraction of the wall or foundation it protects.

That’s why every wall and dig-down we build includes drainage — and why we build stand-alone systems before yours becomes a repair customer.

COMMON QUESTIONS

Drainage questions, answered straight

French drain or area drain — which do I need?

Surface ponding after rain calls for area or channel drains. Water seeping into a garage, crawl space, or from an uphill slope calls for a sub-surface French drain. Most SF hillside lots need both working as one system, and one site walk tells us which.

When should drainage work be done?

Dry season — trenching saturated winter soil is slower, messier, and more expensive. The owners who call us in September have working systems by the first storm; the ones who call during the storm join a queue.

Will a French drain stop my garage from flooding?

If the water is coming downhill or up through the ground, a properly routed French drain with a legal discharge usually solves it. If it’s sheeting across the driveway threshold, the fix is a channel drain. We diagnose the path first — the wrong drain in the right yard fixes nothing.

Do drains need maintenance?

Yes — leaves and silt are undefeated. We build in cleanouts and accessible catch basins, and a once-a-year fall flush keeps the system at capacity when the first atmospheric river lands.

NO-COST · NO-PRESSURE

Get your free estimate

Tell us what’s cracking, settling, or waiting to be built. We’ll walk the site, measure it, and hand you a written price — free, and good whether you hire us or not.

Call now — (415) 687-3728

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