Which condition can indicate a drainfield is not performing due to water table height?

• A. Dry soil with cracking
• B. Increased rainfall without impact
• C. High groundwater or elevated water table reducing infiltration
• D. Deep frost

Answer: (C)

Drainfield performance relies on soil that isn’t saturated so wastewater can infiltrate and be treated as it moves downward. When the groundwater table is high, the pore spaces are already filled with water, leaving little room for effluent to infiltrate. That reduced infiltration means the drainfield can’t absorb wastewater properly, often showing as soggy soil, standing water, or effluent surfacing near the absorption area. This condition—high groundwater or an elevated water table limiting infiltration—is the clear sign that the drainfield is not performing due to water table height.

Dry soil with cracking reflects drying conditions, not a high water table; increased rainfall without impact may not indicate a persistent water-table issue; and deep frost blocks infiltration because the soil is frozen, not because the water table is high.