A flooded septic drainfield occurs when heavy rainfall saturates the soil above your leaching bed faster than it can drain, leaving the system with nowhere to send treated effluent. In Ontario, summer thunderstorms regularly dump 40 to 80 millimetres of rain in under two hours, and that kind of downpour can overwhelm even a healthy, well-maintained drainfield in minutes.

Septic system summer backups occur when the daily volume of wastewater entering the system exceeds what the drainfield soil can absorb, and summer in Ontario creates the conditions for that to happen consistently. Between children home from school, weekend guests, garden irrigation, and extra laundry from outdoor activities, many households send double that volume through the system on a peak summer day without realizing it. For help assessing your system, visit Headwaters Construction.