Drainage, Stormwater & Flood

Yard Drainage and Flooding Engineering

An engineer finds why your yard or basement floods and designs a drainage fix that works, instead of guessing with drains. Typical US fees run $500 to $3,500, and most projects take 1 to 4 weeks.

Typical US fee$500 to $3,500

Typical timeline1 to 4 weeks

Permit drawingsAs needed

What the work involves

For persistent yard ponding, water against the foundation, or runoff from a neighbor, a civil engineer surveys grades, traces where water comes from, and designs a solution such as regrading, swales, French or curtain drains, catch basins, dry wells or sump discharge routing. The engineer makes sure water is not simply shifted onto a neighbor, which can create liability. Contractors then build from the drainage plan.

When you need it

Standing water in the yard days after rain
Water flowing toward or into the basement or crawl space
Runoff coming from a neighbor's property or the street
Erosion, washouts or soggy areas near a slope
A previous French drain did not solve the problem

What you receive

Site visit and drainage assessment
Drainage plan with grades and pipe sizes
Spot elevation survey
Construction details for drains, swales or dry wells

What drives the cost

Estimate for the engineering only. Installation is separate: HomeAdvisor and Angi put typical yard drainage projects at roughly $2,100 to $7,200, French drains at $10 to $50 per linear foot, and regrading at about $500 to $5,000.

Related calculators

Manning's Equation Pipe Flow CalculatorCalculate full-flow capacity and velocity of a circular pipe with Manning's equation from diameter, slope and roughness n.Pipe Slope CalculatorCalculate pipe slope in ft/ft, percent and inches per foot from upstream and downstream invert elevations and pipe length.Gravel CalculatorCalculate cubic yards and tons of gravel or crushed stone for a driveway, path or base course.Roof Runoff and Rainwater Harvesting CalculatorCalculate gallons of runoff from a roof or paved area for a given rainfall depth, for rain barrels, cisterns and drywells.

Frequently asked questions

How much does yard Drainage and Flooding Engineering cost?

Across the US, yard Drainage and Flooding Engineering usually costs $500 to $3,500. Estimate for the engineering only. Installation is separate: HomeAdvisor and Angi put typical yard drainage projects at roughly $2,100 to $7,200, French drains at $10 to $50 per linear foot, and regrading at about $500 to $5,000.

How long does yard Drainage and Flooding Engineering take?

Plan on 1 to 4 weeks from signed proposal to stamped deliverables, longer if a site visit, soil testing or a permit review cycle is involved.

Is a permit required for yard Drainage and Flooding Engineering?

Often not on its own, but the findings frequently lead to work that does need a permit. We tell you which parts of the follow-up work your local building department will review, and can prepare those drawings too.

Will I also need a land surveyor?

Sometimes. Depending on the site, yard Drainage and Flooding Engineering can also involve a land surveyor, landscape architect, drainage contractor or geotechnical engineer. We tell you up front which other professionals your project needs and coordinate with them so the drawings agree.

Who do you provide yard Drainage and Flooding Engineering for?

Most of our clients for this service are homeowners and contractors. Describe your project and one of our engineers will reply with scope, fee and schedule.

Should I call an engineer or a drainage contractor?

For simple problems a contractor may be enough. If water keeps returning, comes from off site, or threatens the foundation, an engineer's assessment avoids paying for the wrong fix.

Can I redirect water onto my neighbor's property?

Generally no. Many states limit altering natural drainage in ways that harm neighbors, and local codes often require runoff to stay on site or reach a drainage system.

Is a French drain always the answer?

No. French drains handle groundwater and seepage. Surface runoff is often better handled with regrading, swales and inlets.

How far should ground slope away from my house?

The International Residential Code generally calls for at least 6 in. of fall within the first 10 ft from the foundation where the lot allows.