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The short answer: find out where the water is coming from before you dig anything. Roof water arriving from a downspout is fixed with a $30 extension. Surface water running in from higher ground is fixed by regrading a swale. Water that falls on the spot and simply will not soak into compacted or clay soil is the only case that genuinely needs a French drain. Grade should fall away from the house 6 inches over the first 10 feet, and any buried drain needs at least 1 percent slope — 1 inch of fall per 8 feet.
Wet yards are the most expensive problem in residential landscaping to fix badly, because people install drainage that addresses the wrong source. A perfect French drain does nothing about a downspout dumping 600 gallons against the foundation during a single storm. Spend the first hour diagnosing.
We are a research desk and never buy or physically handle products; our approach is described in how we rank. The full yard build order is in the landscaping and hardscaping hub.
Step 1: Diagnose the Source
Go outside during the next heavy rain, or within an hour of one ending, and watch. There are only four sources and they have different fixes.
| Symptom | Likely source | Fix |
|---|---|---|
| Wet patch directly below a downspout, gutter overflowing | Roof water | Extend or bury the downspout |
| Water sheets in from a neighbor or a higher slope | Surface runoff | Swale or berm to redirect |
| Whole area ponds where it falls, drains over days | Compaction or clay | French drain, aeration, soil amendment |
| Ground is spongy in dry weather, springs seep | High water table or subsurface flow | Curtain drain, professional assessment |
| Water pools against the foundation | Negative grade | Regrade, urgently |
A percolation test settles the clay question. Dig a hole 12 inches deep and 12 inches wide, fill it with water, let it drain fully, then fill it again and time it. Draining in under 2 hours is free-draining soil. Two to 6 hours is normal loam. More than 6 hours means heavy clay or a compacted layer, and more than 24 hours means water has nowhere to go and any planting there will drown.
Step 2: Do the Cheap Fixes First
Extend the downspouts. An inch of rain on a 1,500 square foot roof is roughly 900 gallons, and a quarter of it can exit one downspout. Discharging that within 3 feet of the foundation is how basements get wet. Extend at least 10 feet out, further if the grade is flat, and discharge onto a splash block, into a bed, or into a buried solid pipe that daylights downhill. Materials are $15 to $60 per downspout and this alone resolves a large share of soggy-yard complaints.
Fix the grade at the foundation. Soil should drop 6 inches over the first 10 feet from the wall. Check it with a string and a line level. If it is flat or falls inward, add soil — not topsoil alone, which is too porous; a compactable soil against the foundation with topsoil above it — and slope it away, keeping the finished grade at least 6 inches below siding and 4 inches below any brick weep holes.
Aerate and amend compacted lawn. A great deal of "poor drainage" is a compacted top few inches from construction traffic. Core aeration followed by a compost topdressing, repeated over two or three seasons, genuinely improves infiltration on lawns and costs very little.
Stop mowing the wet spot when it is wet. Mower traffic on saturated soil compacts it further and creates the ruts that hold the next rainfall.
Step 3: Grading and Swales
The most durable drainage solution is shaping the ground so water leaves on its own. A swale is simply a broad, shallow, gently sloping channel — typically 4 to 10 feet wide and 6 to 12 inches deep at the center, grassed over and mowable — that intercepts surface flow and carries it around or away from the area you want dry.
Aim for at least 2 percent fall along the length of a swale, which is about 2 inches per 8 feet. Make the side slopes gentle enough to mow, roughly 4 feet horizontal for every 1 foot of drop or flatter. A berm on the uphill side, built from the soil you excavate, extends the interception without extra material.
Two rules. Never redirect water onto a neighbor's property in a concentrated stream — in most jurisdictions that is a legal problem as well as a neighborly one. And identify where the water will end up before you start; a swale that carries water to a low point with no outlet has just built you a pond.
Step 4: The French Drain, Built Properly
A French drain collects water from saturated soil and carries it away underground. It is the right tool for chronically wet ground, not for redirecting surface flow, and it is the job most often built wrong.
- Call 811. Free utility locating, a few days lead time. Non-negotiable before a trench.
- Confirm the outlet first. Where does the water go? A daylight point on a lower part of the property, a dry well, or a storm connection if local code permits. Without an outlet you are building an underground reservoir.
- Set the slope with a string line. Minimum 1 percent — 1 inch of fall per 8 feet. Two percent is better. Over a 40-foot run at 1 percent, the trench bottom drops 5 inches end to end. Check as you dig.
- Dig the trench. Typically 12 to 18 inches deep and 12 inches wide for a yard drain; deeper for a curtain drain intercepting subsurface flow along a slope.
- Line it with woven geotextile, with enough width to wrap over the top of the finished stone. This is what keeps silt out of the stone voids. Without fabric the drain clogs in a few years — this is the single most common French drain failure.
- Lay 2 to 3 inches of washed stone, then the pipe. Use rigid perforated PVC with the holes facing down, not corrugated flexible pipe with a sock, which crushes, sags between supports and clogs far sooner.
- Backfill with washed 3/4 inch stone to within a few inches of the surface. Washed, not crusher run — the fines in crusher run are exactly what you are trying to keep out.
- Fold the fabric over the top and finish with a few inches of soil and sod, or leave the stone exposed as a visible feature.
- Add cleanouts at the upstream end and at any bend. A vertical riser with a cap costs a few dollars and makes future flushing possible.
Cost runs $10 to $20 per linear foot in materials and $25 to $60 per linear foot installed. Budget context is in what landscaping costs.
Step 5: Dry Creek Beds and Rain Gardens
A dry creek bed is a surface channel lined with stone that handles visible runoff and looks like a design feature rather than a repair. It is the right answer where water arrives fast during storms and you want it moved somewhere specific without burying pipe.
Build it by excavating a shallow channel 6 to 12 inches deep and 2 to 4 feet wide, lining it with woven fabric, then placing larger stone — 4 to 8 inch cobbles — along the sides and finer gravel in the center. Vary the width, curve it the way water actually flows, and set a few larger boulders asymmetrically so it reads as natural rather than as a stone gutter. Plant the banks with things that tolerate both wet and dry, since the channel is dry most of the year.
A rain garden is the other half of this idea: a shallow depression, typically 6 to 12 inches deep, sited at least 10 feet from the foundation, planted with species that tolerate periodic inundation. It holds runoff and lets it infiltrate over 12 to 48 hours rather than shedding it to the street. Rain gardens only work on soil that percolates — if your test hole took more than 24 hours to drain, amend the soil substantially or choose a different solution.
Step 6: Work With the Wet Spot Instead
Some low areas are not worth fighting. If the spot is away from the house, holds water for a day or two after rain and then drains, planting for the condition is cheaper and better looking than engineering it away. Species that handle periodically wet feet across most of the country include red twig dogwood, winterberry, buttonbush, swamp milkweed, Joe Pye weed, blue flag iris, sedges and switchgrass. Check what suits your USDA zone before buying.
What will not work there: lawn grass, most conifers, lavender, boxwood and virtually anything sold as drought tolerant. Repeatedly replacing drowned shrubs in the same low corner is a recurring expense that a change of plant palette ends permanently.
Mistakes That Waste the Money
Installing pipe before diagnosing. The most expensive error in the category. If the source is the roof, the drain will not help.
Not enough slope. Below 1 percent, silt settles in the pipe. Level drains fail.
Skipping the geotextile. Silt fills the stone voids and the drain stops working within a few years.
Using corrugated pipe with a fabric sock. It sags, holds water in the low spots and clogs. Rigid perforated PVC with holes down is the durable choice.
No outlet. Water has to go somewhere lower. A drain to nowhere is a buried puddle.
Building hardscape first. A new patio is a large impervious surface that changes where water goes. Fix drainage before laying pavers, not after — see how to lay a paver patio.
Sending water to the neighbor. Check local stormwater rules. Concentrated discharge across a property line causes disputes and sometimes citations.
The Verdict
Work in order of cost. Extend the downspouts, correct the grade at the foundation, aerate compacted lawn. If the yard is still wet, shape a swale to redirect surface flow. If the ground itself will not drain, build a French drain with proper fabric, washed stone, rigid pipe and at least 1 percent fall to a real outlet. If the low spot is harmless and away from the house, plant it instead.
Drainage comes first in any landscaping sequence for a simple reason: everything built on top of unresolved water eventually has to be rebuilt. Get it right, then plan the rest with how to plan a yard layout.