Standing Water in Yard
Your yard stays wet, has puddles after rain, or has soggy areas that never dry out.
6 calculators recommended for this problem
Why does water stand here?
Standing water almost always comes down to one of three things: the ground is too flat (or slopes the wrong way) to shed water, the soil is too tight for water to soak in, or the water table is high enough to keep the ground saturated. Diagnosing which one you have is the difference between a fix that works and one that just moves the puddle. Work through the three causes below to identify yours, then pick the matching solution.
Cause 1: Not enough grade (the ground is too flat)
Water needs a continuous downhill path to leave your yard. If a low spot has no outlet, or the ground slopes back toward it, water collects and sits until it evaporates or slowly soaks in. This is the most common cause of puddles that appear right after rain and dry out within a day or two. The fix is to give the water somewhere to go: re-grade to a minimum slope of about 1–2% (roughly 1/8 to 1/4 inch of fall per foot) away from the low point, or install a shallow channel to carry it off. A vegetated swale is the simplest surface channel; where a surface channel is not practical, a subsurface collector like a French drain or an inlet at the low point does the same job below grade.
Cause 2: Tight soil (water cannot infiltrate)
Even a well-graded low spot will pond if the soil beneath it barely drains. Heavy clay and compacted fill have very low infiltration rates, so rain sits on the surface long after the storm ends — the tell-tale sign is a soggy area that stays wet for days, not hours. Confirm it with a simple percolation test: dig a hole, fill it with water, and time how fast the level drops. If infiltration is slow, a solution that relies on soaking water into the ground (a dry well or rain garden) must be sized generously for the poor perc rate, or paired with an underdrain that carries the collected water to a real outlet.
Cause 3: High water table (the ground stays saturated)
If soggy areas persist even in dry weather, or water seeps back into a hole you just dug, the water table may sit near the surface. When groundwater is high, infiltration-based fixes fail because the ground has no spare capacity to accept more water — a dry well simply fills up. The right approach is an interceptor drain that collects and carries groundwater to a lower discharge point by gravity, rather than trying to soak it away. Read more about how subsurface systems handle groundwater before choosing an approach.
Many yards have more than one cause at once — a flat area over clay soil is a classic combination. When in doubt, fix the grade first (it is the cheapest change and often solves the problem on its own), then add infiltration or a subsurface drain only if water still stands. The calculators below help you size whichever solution fits your site.
Recommended Calculators
These tools are most useful for solving "standing water in yard" problems.
French Drain Calculator
Calculate French drain capacity, pipe sizing, and storage volume. Design subsurface drainage systems using Darcy's Law and Manning's equation. Free professional-grade drainage calculator.
Dry Well Calculator
Calculate dry well sizing for stormwater infiltration. Determines storage volume, infiltration capacity, and drawdown time using ASCE MOP 77 methodology.
Rain Garden Calculator
Calculate rain garden sizing for stormwater management. Determines required area, storage volumes, and infiltration capacity using ASCE and EPA methodology.
Vegetated Swale Calculator
Calculate vegetated swale hydraulics including normal depth, velocity, and capacity using Manning's equation with variable roughness based on vegetation retardance.
Area Drain Spacing Calculator
Calculate optimal area drain spacing based on surface slope, ponding constraints, and drain capacity. Uses sheet flow analysis from TR-55 and HEC-22 methods. Professional drainage design tool for civil engineers.
Catch Basin Calculator
Calculate catch basin sizing, outlet pipe capacity, and sediment storage volume. Design storm drainage inlets using Manning's equation. Free professional-grade hydraulics calculator.
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