DRAINAGE & FOUNDATION / CENTRAL FLORIDA
Yard drainage & French drains
Water pools in the yard, leaves the lawn soggy or runs toward the house.
What FAS does.
FAS installs yard drains, French drains and collection points to address recurring wet areas. We look at where the water comes from and where it can go, then explain the proposed pipe route and outlet. The quote identifies the drainage work and the areas affected by installation. Site checks help determine whether a French drain, surface drain or another approach fits your property.
What we check.
- Where water collects and how long it stays after rain.
- The ground levels and a suitable place for water to discharge.
- Access around trees, utilities, landscaping and existing drains.
What happens next.
- Show us the wet areas and any existing drains.
- Review the proposed drainage route, work and quote.
- Approve the site-verified work before installation scheduling.
Common questions.
Do I need a French drain?
That depends on where the water comes from and the site conditions. A surface drain or changes to roof runoff may be a better fit.
Can you use the drains already in my yard?
We can review them. Their condition, route and outlet need to be checked before connecting new work.
Optional: explore how this drainage principle works
SEE THE PRINCIPLE
A picture you can explore.
Change a control to see why the details matter. This example does not diagnose your property.
ONE RAINSTORM. THREE SURFACES.
Watch the water add up.
Change the rain or an area. See how each surface contributes to the estimated flow.
The layout is a schematic. The bars below show the calculated contributions; arrows identify sources, not drainage routes.
Where the runoff comes from
Shared scale: 0–200 GPM55.2% of this example’s total
19.9% of this example’s total
24.9% of this example’s total
ILLUSTRATIVE RUNOFF RATE
276.87 GPM
Gallons per minute, for the rain and areas above.
Effective collection area: 3,620 sq ft of the 8,800 sq ft entered.
This example assumes roof 1.00, hardscape 0.90 and lawn 0.15. These are illustration settings, not verified values for your property.
THE CALCULATION
Each surface gets a share.
A runoff coefficient represents the fraction of rainfall included in the runoff estimate. Multiply each area by its assumed coefficient, add those contributions, then apply the rainfall intensity.
GPM = rain intensity ×
(roof + 0.90 × hardscape + 0.15 × lawn) ÷ 96.23
Areas are in square feet and intensity is in inches per hour.
Formula: NDS, Principles of Exterior Drainage, printed page 26. The guide’s coefficients depend on surface and soil conditions; it does not establish this example’s 0.15 lawn setting.
A WORKED EXAMPLE
Try the starting values.
2,000 sq ft of roof + 0.90 × 800 sq ft of hardscape + 0.15 × 6,000 sq ft of lawn = 3,620 effective sq ft.
At the illustrative intensity of 7.36 inches per hour:
7.36 × 3,620 ÷ 96.23 = 276.87 GPM.
This estimates a runoff rate, not storm volume, ponding depth or drainage performance. It does not choose a pipe, pump or system. Property conditions and an appropriate local rainfall intensity need assessment before design decisions.
Discuss your property with FAS