Cost, looks, and lifespan side by side — and the reason a French drain is the wrong default for most Hill Country yards. The first Site Read is free.
Bioswale: $30–$60/ftFrench drain: $50–$120/ftFree Site Read
Two answers to the same complaint — water sitting where it shouldn't. One buries a pipe to carry the water off. The other shapes the ground and plants it so the water sinks in. They cost different money, last different lengths of time, and look like nothing alike.
Most contractors quote a French drain by default, because it's the answer they know. Here's the honest comparison so you can tell which one your yard actually needs.
§ 1 · Side by side
The comparison.
Cost
Bioswale wins
Bioswale runs about $30–$60 per linear foot. A French drain runs about $50–$120 per linear foot — buried pipe and geotextile cost more to build than soil and plants.
Lifespan
Bioswale wins
A French drain lasts about 8–20 years before the geotextile clogs. It's at full capacity day one and degrades. A bioswale improves over time as the planting establishes.
Looks
Bioswale wins
A bioswale is planted — native sedges and inland sea oats — so it reads as part of the garden. A French drain disappears underground and gives you nothing on the surface.
When it wins
French drain
Under hardscape, beside a foundation, or anywhere surface water has no place to go and must be carried off in pipe. Real jobs — just not most yards.
The short version: a bioswale is cheaper to build, looks like a garden, and gets better with age. A French drain is the right tool for a narrow set of jobs — and overbuilt for the rest.
§ 2 · The cost gap
Where the money goes.
Bioswale ≈ $30–$60 per foot. You're paying for grading and planting. The soil and the roots do the infiltration. Often a one-day install.
French drain ≈ $50–$120 per foot. You're paying for trenching, perforated pipe, washed stone, and geotextile fabric. The dig is most of the cost — caliche makes it worse.
Why the spread. A French drain is a buried mechanical system; a bioswale is a shaped, planted bed. One has parts that wear out. The other is a living thing that matures.
§ 3 · Lifespan
One wears out. One matures.
A French drain has a service life of about 8 to 20 years. Over that time silt and fines work into the geotextile and the gravel, the fabric clogs, and the drain stops moving water — and there's no easy fix but to dig it out and rebuild. It's at full capacity the day it goes in and degrades from there.
A bioswale runs the other direction. As the planting establishes, the roots open the soil, infiltration improves, and the swale handles more water year over year. You're not buying a part that ages out — you're starting a system that gets better.
§ 4 · When a French drain is right
Use the right tool.
This isn't an argument against French drains. It's an argument against using one by default. There are jobs where a French drain is exactly correct: under hardscape, beside a foundation, or anywhere surface water has no place to go and has to be carried away in pipe. Those are real problems, and we build French drains for them.
But a French drain is overbuilt for roughly 70% of the residential drainage problems we see in the Hill Country — places where a regrade, a downspout extension, or a planted bioswale solves the problem for less money and a longer life. The skill isn't knowing how to dig a trench. It's knowing when not to.
A bioswale is cheaper. A planted bioswale runs about $30 to $60 per linear foot; a French drain runs about $50 to $120 per linear foot. The bioswale uses soil and plants to do the infiltration instead of buried pipe and geotextile, so it costs less to build and often installs in a day. That gap is most of the reason we don't default to a French drain.
Which lasts longer, a bioswale or a French drain?
A French drain has a service life of about 8 to 20 years before the geotextile clogs with silt and fines and the drain stops moving water. It's at full capacity on day one and degrades from there. A bioswale runs the other direction: it improves over time as the planting establishes, the roots open the soil, and infiltration gets better year over year. One is a part that wears out; the other is a living system that matures.
When do I actually need a French drain?
Use a French drain where it's the right tool — under hardscape, beside a foundation, or anywhere surface water has no place to go and has to be carried away in pipe. Those are real jobs and we build them. But a French drain is overbuilt for roughly 70% of the residential drainage problems we see in the Hill Country, where a regrade, a downspout extension, or a planted bioswale solves the problem for less. The point isn't to avoid French drains — it's to use one only where it actually wins.
Will a bioswale look like a ditch?
No. A bioswale is planted, not bare. We build it with native sedges and inland sea oats so it reads as part of the garden, not a trench — a shallow planted depression that greens up and holds its shape. When it's dry it looks like a bed; when it rains it does its job. A French drain, by contrast, disappears underground and gives you nothing on the surface. A bioswale earns its footprint.
Start here
Find out which one you need.
We walk the storm path on your property and tell you straight which tool fits — bioswale, French drain, or neither. No charge — the first Site Read is free.