Backyard Drainage Ideas That Fix the Water, Not the Symptom

Most drainage money is spent on the wrong fix. Four different problems look identical from the kitchen window, and a French drain only solves one of them.

Find the cause first

Walk the yard during rain, not after. Twenty minutes in a downpour tells you more than any amount of guessing once it dries.

The fixes, matched to the cause

Regrading — the cheapest real fix

If the ground falls toward the house, or there is a bowl with no exit, moving soil solves it outright.

• Target about one inch of fall per foot for the first ten feet from the foundation
• Use the soil you already have where possible — spoil from a different part of the yard
• Keep soil six inches below siding and below any weep holes or vents
• Compact in layers rather than dumping and raking, or it settles back within a season
• Reseed or turf immediately, because bare regraded soil erodes in the first storm

French drain — for water arriving, not water sitting

A trench with washed stone and a perforated pipe that intercepts water and takes it elsewhere.

1. Confirm you have an outlet lower than the drain. Without one this is a soakaway, not a drain, and it will fill and stay full
2. Dig across the flow, uphill of the wet area, not through the middle of it
3. Maintain continuous fall to the outlet — about one percent minimum, and check it with a level rather than by eye
4. Line the trench with filter fabric, wrapping over the top of the stone. Silt is what kills these
5. Washed stone only. Pea gravel or anything with fines in it clogs
6. Perforations face down, which is counter-intuitive and correct — water enters from below as the table rises
7. Daylight the outlet or run it into a dry well

Dry well — for water with nowhere to go

A buried void that holds water while it soaks away.

• Size it to the catchment and your soil, not to the hole you feel like digging
• Test your percolation first. Dig a foot-deep hole, fill it, and time the drop. Clay that takes a day to empty will not support a dry well
• Set it well away from the foundation — at least ten feet, further on clay
• Wrap in filter fabric and cap with soil or a grate

Rain garden — the one that looks intentional

A shallow planted depression that holds runoff and lets it infiltrate.

• Six to nine inches deep, flat-bottomed, with a defined inlet and an overflow
• Amended soil: roughly half sand, a quarter compost, a quarter topsoil for anything heavy
• Plant species that tolerate both wet and dry, because it is a bog for two days and a dry bed for three weeks
• Site ten feet or more from the house, never over a septic field

Dry creek bed — a swale you can look at

• Dig and grade it first. A real channel with fall, then the stone
• Larger stone in the channel, smaller at the edges, with the sizes mixed rather than uniform, or it reads as a stone gutter
• Filter fabric underneath to stop it sinking into the soil
• Curve it. Straight lines look like a trench full of rocks

Stone laid on flat ground moves no water. That is the difference between a drainage feature and a decoration, and it is the whole of it.

What does not work

• A French drain into a hole with no outlet. It fills, then it is a pond with a lid
• Pea gravel or unwashed stone in a drain trench. Fines migrate and clog it
• Perforated pipe with the holes up
• A drain across flat ground. No fall, no flow
• Sand on clay. The classic amendment mistake — sand plus clay without large volumes of organic matter makes something closer to concrete
• Topsoil over the puddle. It moves the low spot by one season
• Draining onto the neighbour’s land. Usually unlawful, always a dispute

Order of operations

1. Watch it rain. Identify which of the four causes you have
2. Fix the downspouts. Cheap, fast, and often the whole answer
3. Regrade if the ground falls the wrong way
4. Then and only then consider a French drain, dry well or rain garden
5. Deal with compaction separately — core aeration and organic matter, every year on clay

Working in that order means most yards are fixed before the expensive line item is reached.