How do I fix poor drainage in a New Brunswick backyard?

Fixing poor drainage in a New Brunswick backyard starts with identifying the cause — whether it is compacted clay soil, improper grading, a high water table, or surface runoff from neighbouring properties — and then choosing the appropriate solution, which may range from simple regrading to installing a French drain system. Poor drainage is one of the most common landscaping problems across NB, particularly in the clay-heavy Saint John River valley around Fredericton and low-lying coastal areas near Moncton and Saint John.

Regrading is often the simplest and most effective first step. Your yard should slope away from your home's foundation at a minimum grade of 1-2%, which means a drop of at least 6 inches over the first 10 feet from the foundation wall. Many NB properties lose this grading over time as soil settles, mulch beds build up, and landscaping changes alter drainage patterns. Professional regrading costs $1,000 to $3,000 in New Brunswick depending on the area involved, and it can often solve foundation-area ponding without more expensive interventions.

For persistent wet areas farther from the house, a French drain is the standard solution. This is a perforated pipe laid in a gravel-filled trench that collects subsurface water and redirects it to a lower discharge point or dry well. In New Brunswick, French drains should be installed at a minimum depth of 18-24 inches, though going below the frost line (1.2-1.5 metres in NB) provides the best long-term performance by preventing pipe damage from freeze-thaw heaving. A typical residential French drain system costs $1,500 to $4,000 installed, depending on length, depth, and the complexity of the discharge point.

Spring thaw creates the worst drainage conditions in NB, when frozen subsoil prevents meltwater from percolating downward, creating saturated, swampy conditions that can persist for weeks. Design any drainage solution for this worst-case scenario rather than average summer conditions. Swales — shallow, gently sloped channels — can direct surface water away from problem areas without the cost of buried pipe. Rain gardens planted with moisture-tolerant native species like red osier dogwood and sedges provide attractive, low-maintenance drainage solutions for moderate water volumes.

Soil amendment can significantly improve drainage in NB's heavy clay soils. Incorporating 3-4 inches of coarse compost into the top 8-12 inches of clay soil breaks up the dense structure and creates air pockets that allow water to infiltrate. Adding coarse sand to clay is a common but risky approach — if the ratio is wrong, you can create a concrete-like mixture that drains worse than pure clay. For serious drainage problems affecting your foundation, consult a qualified landscaper or drainage contractor who understands New Brunswick's frost conditions and water table patterns.

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