Can you install a French drain yourself? When DIY works in DFW, and when to hire

The three questions that decide it

1. Is there somewhere for the water to go?

A French drain doesn't make water disappear. It gives water a path to somewhere lower. Before you dig, find that spot: the street, a lower part of your own yard, or a drainage easement. If water has to run uphill to leave the yard, the drain won't work without a sump pump.

Dry wells usually aren't an answer here. A dry well is a gravel pit that lets water soak into the ground. One state fact sheet lists them as unsuitable in soil that's more than 30% clay, and North Texas clay often runs around 55%. Plan for a downhill outlet or a sump pump instead.

Two rules matter:

• Don't send it onto a neighbor's property in a way that damages it. Texas law bars diverting surface water in a way that damages someone else's property, and the neighbor can sue. A drain that gathers water and releases it at your property line can be exactly that kind of diversion, even if the water already flowed that way more slowly. Aim the outlet at the street or a spot on your own lot.
• Ask the city before tying into a curb, alley or storm inlet. That's public property. Each city page on this site lists who to call.

2. What's buried in the way?

Call 811 at least two business days before you dig. The Damage Prevention Council of Texas says the law requires it even in your own backyard, and it's free. The utility companies will mark their lines.

But 811 won't mark everything. Texas811 says utilities may not mark lines that run from the meter onto private property or to the house. Those private lines are yours to find, and they're often exactly where a drainage trench goes:

• Gas to a grill, fire pit or pool heater
• Power to a shed, gate or landscape lights
• Sprinkler lines
• Your sewer line

If you have any of these, hire a private utility locator or dig by hand near them. Then walk the trench line for the rest:

• Sprinkler lines. You can repair your own system. Anyone you pay to work on it needs a TCEQ irrigation license: a licensed irrigator, or a licensed irrigation technician working for one.
• Tree roots. Large roots make digging slow and can crush or clog pipe later.

3. Can you dig this clay?

North Texas clay is hard work. When it's dry it's close to rock, with cracks up to a few inches wide. When it's wet it's heavy and sticky. A 60-foot trench, 18 inches deep and a foot wide, means moving about 3 cubic yards of it by hand and hauling it away. Then you buy and carry in about the same volume of washed gravel, which weighs several tons. Renting a trencher helps in open ground but not around trees, beds or fences.

When DIY makes sense

• A short run, under about 40 feet, in open lawn
• An obvious low spot with a clear downhill path to the street or a lower part of the yard
• No private gas or electric lines near the route, and few sprinkler lines
• You're comfortable digging and hauling a few cubic yards of clay and gravel

When to hire

• Water is moving toward the foundation. Getting that wrong costs far more than the drain.
• There's no obvious downhill outlet, so the job needs a sump pump or a connection the city has to approve.
• The trench crosses private gas or electric lines, lots of sprinkler lines, tree roots or concrete.
• The whole yard is wet, not one spot. That often needs regrading, not just a drain.

For what hiring costs, see the cost guide.

How a French drain is built

1. Check the fall before you dig. For a standard 4-inch pipe, the usual minimum slope is 1/8 inch per foot. Over a 60-foot run, that's 7.5 inches. If you start 18 inches deep on a flat lot, the far end has to be at least 25.5 inches below where you started, and the outlet has to be lower still. That's where DIY drains most often fail: the outlet ends up buried with nowhere to go. Check it with a string line or a laser level first.
2. Dig the trench. Guides commonly recommend 18–24 inches deep and at least 12 inches wide.
3. Line it with filter fabric so clay doesn't clog the gravel.
4. Add a few inches of washed gravel, then perforated pipe with the holes facing down.
5. Cover the pipe with more gravel and fold the fabric over the top. If you're catching water that pools on the surface, finish with gravel to the top or add a catch basin. Covering the trench with clay soil seals it off.
6. Finish at the outlet with a pop-up emitter, a splash area, or an approved connection.

Keep roof water separate. Run downspouts in solid pipe to their own outlet, never into the perforated French drain. Roof water overloads the trench and fills the pipe with sediment.