Understanding Your Septic Drain Field

Most homeowners know they have a septic tank. Far fewer understand the drain field — the critical component that actually treats and disperses the wastewater. Protecting it should be a top priority.

How the drain field works

Liquid effluent from the septic tank flows into perforated pipes buried in gravel-filled trenches. The effluent slowly seeps into the surrounding soil, where naturally occurring bacteria filter out harmful pathogens before the water reaches the groundwater table.

What can damage a drain field

Overloading the system with too much water (running multiple appliances at once, doing many loads of laundry in a single day), driving vehicles over the field, planting trees with aggressive root systems nearby, and — most commonly — allowing too many solids to accumulate in the tank and migrate into the field.

Protecting your drain field

Keep vehicles, heavy equipment, and deep-rooted trees away from the drain field area. Spread out high-water-use activities throughout the week. And pump your tank regularly — this is the single most effective way to prevent solids from reaching the field.

When the drain field fails

Signs include surfacing effluent, persistent wet areas over the field, and sewage odors outside. A failing drain field is serious and should be addressed promptly. In some cases, remediation is possible; in others, replacement is necessary. Either way, get a professional assessment as soon as possible.