Drainage installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What drainage installation is

Drainage installation carries surface and groundwater away from a house or yard with French drains, catch basins, downspout lines or swales. A good drainage plan starts with finding where the water collects and where it can safely go, because the fix depends on the water path more than on the spot that looks wet.

Signs you need it

  • Water pools in the yard for days after rain, or the lawn stays soggy in low spots
  • The basement or crawlspace is damp, and the water seems to come in from the outside through the wall or floor
  • Downspouts discharge right next to the foundation, and the soil at the wall stays wet
  • A driveway, patio or walk holds water at its edge and washes soil out along the side
  • Soil has washed out from the base of a retaining wall or a slope, leaving an exposed or unstable edge
  • A low corner of the lot floods during storms and the water has nowhere to go

What the pro does

  • Trace the water path on the site during and after a storm, and check where the water enters and where it can leave
  • Locate the buried lines, the septic field and any utilities before any trench or excavation
  • Dig the trench to the grade that moves water, setting the pipe in drainage stone with a fabric wrap around it
  • Connect the drain to a safe discharge point, such as a storm outlet, a dry well or a permitted daylight outlet
  • Install catch basins, cleanouts or downspout extensions where the design calls for them, with the grates set flush
  • Backfill with clean stone and topsoil, grade the surface so it sheds water toward the outlet, and test the flow

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Length of the drain run and the number of catch basins, cleanouts or inlets along it
  • Depth of the trench and the soil type, since rock or clay slows the dig and changes the stone needed
  • Discharge point and how far the water must travel, including whether a pump is needed to reach the outlet
  • Access for the trencher or excavator, especially around fences, decks, patios and landscaping
  • Amount of surface grading and the plants or hardscape that must be removed and restored
  • Permits and inspections for the outlet, and any connection to a storm line or a public system

What a written quote should spell out

  • Drain length, pipe size and type, and the trench depth and slope named in the proposal
  • Stone, fabric and the backfill material used around the pipe
  • Catch basins, cleanouts, grates and the downspout connections, listed separately
  • The discharge point, and whether it is to a storm outlet, a dry well or a daylight outlet
  • Utility locate and the protection of any septic field or line in the work path
  • Restoration of the lawn, landscaping or hardscape disturbed by the trench

Questions to ask before you hire

  • Where will the water go once it leaves the drain, and is that outlet allowed?
  • How deep is the trench, and what slope will the pipe have?
  • What pipe and stone do you use, and why is that the right choice for my soil?
  • How will you protect the septic field, the utility lines and the plants along the route?
  • Will the drain be tested for flow before the trench is backfilled?
  • Do I need a permit, and who will pull it for this outlet?

Red flags

  • Installs a French drain without finding where the water will discharge
  • Says the drain will work without checking the slope of the pipe
  • Discharges water toward a neighbor's yard or into a septic field
  • Skips the fabric wrap around the pipe, which lets soil clog the drain over time
  • Does not mark the buried utilities or the septic line before digging the trench

What you can do yourself

A homeowner can clean out downspouts, extend downspout discharge away from the foundation, and grade soil slightly away from the house with topsoil. Call a pro for trenched drains, catch basins, outlets, sump connections or any drain that must pass under a driveway or near a septic field. Trenches can collapse, and buried lines can be struck, so call for a utility locate before any digging and keep out of trenches deeper than your knees.

Licenses and permits

Drainage installation is commonly done by licensed contractors, and trenched drains, storm outlets and connections to public or septic systems often require a permit in many areas. Check with your state or local licensing agency and your local building department before work starts, especially for any outlet that leaves the property.

Drainage installation questions

Is a French drain the right fix for my wet yard?

It can be, but only when the water is moving through the ground and has a safe place to go. A pro should check the water path and the discharge before recommending a French drain over grading or a swale.

Why does my drain clog after a few years?

Clogging usually comes from soil getting into the stone, a missing fabric wrap or a pipe that has no clean-out access. Ask the pro how they wrap the pipe and where the cleanouts are placed.

Can I drain water into the street or a neighbor's yard?

Draining to the street or onto a neighbor's property can be restricted by local rules and can cause disputes. Ask the pro and your local building department what outlet is allowed before the work is planned.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

Edit history

How it works

  1. 1. Describe the job

    Pick the service, add your ZIP and a sentence about what is going on.

  2. 2. Pick the pros you want

    See screened pros who serve your ZIP and choose who you want to hear from.

  3. 3. They reach out

    They contact you the way you chose: phone, email or in-app messages.

More concrete, masonry and paving guides

Find a pro near you

Find a pro

About this guide

Request drainage installation