Drainage
Catch Basin vs. French Drain: Which One You Need
Catch basins collect surface water at a low point; French drains intercept water moving through soil. How to tell which problem you have, costs for each, and when a yard needs both.
These two get confused because both end in a buried pipe, but they solve opposite problems, and installing the wrong one is a common and expensive miss: a French drain under a puddle does little (surface water enters slowly through the cap), and a catch basin does nothing for soil that is saturated from below. Diagnose first, dig second.
The 10-minute diagnosis
| Symptom | Water type | Fix |
|---|---|---|
| Puddles during rain, gone within hours | Surface runoff | Regrade, or catch basin if regrading is impossible |
| Water sheeting across paving to a low corner | Surface runoff | Catch basin or channel drain at the collection point |
| Lawn squishy for days after rain | Subsurface / perched water | French drain through the wet zone |
| Hillside seep, wet band across a slope | Subsurface lateral flow | Interceptor French drain above the wet band |
| Wet basement wall or floor | Subsurface at depth | Foundation drainage + roof water fixes first |
| Low spot that collects the whole yard's rain and holds it | Both | Basin for the surge, drain if soil stays saturated |
The full diagnostic tree, including the grading and downspout causes that masquerade as drainage problems, is in the standing water guide.
How each is built
Catch basin: a plastic or concrete box set flush at the low point, grate on top, sump below the outlet to trap sediment, and solid 4-inch pipe leaving at 1-2% to daylight, a pop-up, or a dry well. The basin is easy; the pipe run to a legal, lower discharge point is the real project.
French drain: a fabric-lined trench with washed stone and perforated pipe at ~1% fall, built as detailed in the install guide and sized with the calculator.
Cost comparison (2026)
| DIY materials | Installed | |
|---|---|---|
| Catch basin + 30 ft solid pipe | $120-$300 | $500-$2,000 |
| 50 ft French drain | $280-$540 | $500-$3,250 |
| Regrading the low spot | $0-$200 (sweat + fill) | $500-$3,000 |
Note the first row of fixes in every drainage decision: if a shovel and fill dirt can raise the low spot or restore fall away from the area, grading beats both boxes and trenches on cost and maintenance. The comparison against shaped-ground solutions continues in French Drain vs. Swale.
When you need both
Flat lots with clay soil often produce the hybrid case: rain ponds at the low point (surface) and the ground beneath stays saturated for days (subsurface). The clean solution is a catch basin for the surge with its own solid pipe, and a French drain through the saturated zone with its own perforated run, sharing a trench where convenient but never a pipe. One outlet, a dry well or daylight point, can serve both if sized for the combined flow.
Sources & standards: quantities and factors in this guide follow the references documented in our methodology, including ACI 302/318 (concrete practice), OSHA 29 CFR 1926 Subpart P (excavation safety), ASTM aggregate designations, and the International Residential Code. Local codes, climate, and site conditions govern.
Frequently Asked Questions
What is the difference between a catch basin and a French drain?
A catch basin is a grated box at a low point that swallows surface water, puddles and runoff, into a solid pipe. A French drain is a gravel-and-perforated-pipe trench that intercepts water moving through the soil. Surface water: basin. Soil water: French drain.
How do I know which one I need?
Watch during and after rain. Water sheeting or ponding on the surface within hours of rain is a catch basin or grading problem. Ground that stays squishy for days after rain, or a wet basement, is subsurface water: a French drain problem.
How much does a catch basin cost?
A 12-inch residential basin with grate runs $40-$120 in parts, plus solid pipe to the discharge point. Professionally installed with a pipe run, expect $500-$2,000 depending on distance and surface repair.
Can a catch basin and French drain share a pipe?
Keep them separate. A basin's surge of silt-heavy surface water will foul a French drain's stone bed. If trenches must share a route, run the basin's solid pipe alongside the drain, not into it.
Do catch basins need maintenance?
Yes, that is their tax: the sump below the grate collects leaves and sediment and needs scooping a few times a year. A neglected basin becomes a mosquito nursery and then a clog.