When your garden floods or your soil stays soggy, you face a choice: French drain vs soakaway.
A French drain is a trench filled with gravel (sometimes a perforated pipe wrapped in geotextile) that redirects surface or subsurface water away from trouble spots. A soakaway, by contrast, is a buried pit or crate system that captures water and lets it seep into the soil over time. They’re both handy, but they solve different problems.
This article breaks down how each works, what challenges each addresses, and how to make the right choice.
A French drain channels water. You dig a sloped trench, line it with geotextile, add gravel and a perforated pipe, then backfill. Water seeps through the ground into the trench and flows through the pipe to a designated discharge point. French drain systems stop water from pooling near foundations or saturating lawns.
A soakaway contains water in a pit filled with rubble or plastic crates. Wrapped in geotextile and buried, it allows water to fill the voids and slowly percolate into the surrounding soil. Soakaways hold runoff before letting it seep naturally away.
French drains make sense if runoff or groundwater is creating persistent damp spots near the house, along retaining walls, or on slopes. They handle water before it reaches your building and need a gradient to work properly. They work fast to relieve pressure.
Soakaways suit areas where water builds up due to impermeable surfaces, and nothing nearby can absorb it. They slowly release water into the ground. They are low profile and ideal when you want to reduce surface flooding, like under driveways or patios, while supporting sustainable drainage systems (SuDS) compliance.
Not sure which system you need? Use this quick checklist:
Flooding near foundations or on sloped ground?
A French drain is usually the better choice to intercept and redirect water before it causes structural issues.
Water pooling on driveways, patios, or flat areas?
A soakaway helps disperse runoff into the ground, especially when there's little natural slope.
Trying to meet driveway drainage regulations?
Soakaways are commonly used to prevent surface water from running into public drains or roads.
Soil type is heavy clay or poorly draining?
Soakaways may struggle. In this case, FS Group can carry out a soil percolation test and advise whether a French drain or slope adjustment will perform better.
Unsure about layout or compliance?
Let FS Group inspect your property and design a drainage plan that actually works for your ground, water load, and building type.
Installing a French drain isn’t just about digging a trench and throwing in gravel. It needs the right slope for gravity flow, correct placement of geotextile fabric to prevent clogging, and a safe outfall point that won’t create problems downstream.
For soakaways, the process starts with a percolation test. This confirms whether your soil can absorb water at the right rate. If it can’t, the soakaway may overflow or fail. The system also needs to be sized properly to match the expected volume of runoff.
Soakaways must meet Building Regulations Part H and be built with the right materials, especially if they’re going under a driveway, where load-rated crates are essential.
Poorly installed systems do more harm than good. Undersized soakaways can flood, overloaded French drains can collapse, and both can cause long-term erosion or damp issues if not properly designed.
At FS Group, we don’t guess. We test your ground, check compliance requirements, and install drainage systems built to last. Whether you're dealing with clay soil, a sloped garden, or a paved driveway, we tailor every installation to perform, comply, and protect.
French drains intercept and divert water through a channel system. Soakaways store water and release it into the ground slowly. If water is racing toward a building or slope, French drains are effective. If runoff pools and needs dispersal, soakaways work well. Complex cases may need both.
Either way, don’t let water win. FS Group assesses properties fast, tests soil, and installs the right drainage solution on time. Book your inspection today and fix drainage before it causes real damage.
.png)
.png)
.png)
