Brentwood, CA · East Contra Costa
Downspout Drainage and Catch Basins in Brentwood, CA
A lot of yard flooding is roof water. A typical roof sheds a large volume in a heavy storm, and a downspout that empties at the foundation puts it exactly where you don't want it. Underground downspout lines, catch basins, and channel drains move surface water away before it soaks in.
Cited cost ranges · No obligation
Signs the problem is surface water
Puddles right under the downspouts
Water pooling or soil eroding at the base of a downspout is roof water with nowhere to go.
The patio floods in a storm
Hardscape added over the years can trap water against the house or in a low corner. A catch basin or channel drain collects it.
Water at the garage or driveway
A driveway that slopes toward the garage can send water under the door. A channel drain across the slope intercepts it.
Splash blocks that don't help
A short extension or splash block moves water a foot or two. In clay soil, that's often still too close.
Underground downspout lines
Each downspout connects to solid (not perforated) pipe buried in a shallow trench. The pipe carries roof water to an outlet: a pop-up emitter in the lawn that opens when water flows and closes when it stops, a daylight point on a lower part of the yard, a curb outlet where the city allows it, or a dry well. Solid pipe matters here: the goal is to move water away, not leak it back into the soil next to the house.
Catch basins and area drains
A catch basin is a box with a grate set at a low spot in a lawn, planter, or patio. Water drops in, debris settles in the basin's sump, and the water exits through a pipe to the same kinds of outlets. Smaller area drains do the same in planters and narrow side yards. They work for water that collects on the surface; they don't help water moving underground, which is a French drain job.
Channel (trench) drains
A channel drain is a long, narrow grated trough set flush with concrete. It's the usual answer for a driveway that slopes toward the garage, the edge of a patio that sheds water toward the house, or a pool deck. It intercepts a sheet of water along a line rather than at a single point.
Which one fits?
| Where the water is | Usual fix |
|---|---|
| Pooling under downspouts | Underground downspout lines to a pop-up emitter, daylight, curb outlet, or dry well |
| A low spot in the lawn or a planter | Catch basin or area drain, piped to an outlet |
| Across a driveway toward the garage | Channel drain at the base of the slope |
| Along a patio edge next to the house | Channel drain or catch basins, plus a check of the patio's slope |
| Lawn soggy for days, not just puddles | Likely subsurface water: see French drain installation |
What it usually costs
Angi's 2026 yard drainage data puts catch basin installation at about $600–$2,000 (the basin itself $50–$200) and trench (channel) drains at $30–$70 per linear foot. Underground downspout lines are priced largely by trench length and outlet, similar to shallow drain work. Every quote depends on the route, hardscape cutting, and where the water ends up.
Published ranges, not a quote; Bay Area jobs often cost more than national averages. Full breakdown: French drain cost in Brentwood.
What to check in a quote
- Solid pipe for downspout lines, and its diameter
- Where each line ends, and whether the outlet is allowed and practical
- Cleanouts or debris filters at the downspout connections
- How concrete or pavers are cut and patched
- Whether gutter cleaning or repair is part of the job (gutters themselves are a separate trade)
Check any contractor, including one you find here
- Ask for the contractor's CSLB license number and look it up at cslb.ca.gov. The CSLB site also explains when a California contractor license is required.
- Get the quote in writing: the length and depth of each drain, the pipe and gravel, filter fabric, where the outlet is, and how the yard will be restored.
- Be wary of large deposits or cash-only terms. Ask who marks utilities through 811 and who handles any permit the city requires.
- Ask the contractor to show you the route and the fall from the farthest inlet to the outlet, and what warranty covers the work.
This site is an independent referral service, not a contractor. Your request goes to an independent local drainage contractor, who gives the quote and does the work. How this works
Common questions
Where should downspouts drain?
Away from the foundation, to a point where the water can leave the property or soak in safely: a pop-up emitter in the lawn, a daylight point downhill, a curb outlet where your city allows it, or a dry well.
Should downspouts connect to a French drain?
Usually not directly. Roof water is better carried in solid pipe to its own outlet. Feeding a perforated French drain with roof water can overload it and push water back into the soil near the house.
What's the difference between a catch basin and a French drain?
A catch basin collects water that sits on the surface at one spot. A French drain collects water moving through the soil along a trench. Many yards need both.
How much does a catch basin cost to install?
Angi's 2026 data puts catch basin installation at about $600–$2,000, including piping to an outlet. See the cost guide for related costs.
Related drainage fixes
Dry wells
An underground chamber that lets drain water soak in. Useful as an outlet, limited by clay soil.
Standing water & soggy yards
Work out what's causing the water, then match it to the right fix.
French drain installation
Underground pipe and gravel that collects soggy-yard water and carries it to a real outlet.
Hiring a drainage contractor
A quote checklist, the questions to ask, red flags, and how to check a license.
Talk to a local drainage pro
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