Lateral lines run from a septic system to the drain field. Contaminants, pollutants and pathogens are filtered out in the septic biomat containing aerobic bacteria. The remaining effluent flows through lateral lines to equally distribute effluent throughout the field.

A properly installed lateral line system should last up to 20 years. The life of the lines are shortened if they are not maintained and cleaned.

Backup occurs when lateral lines are blocked or clogged by non-biodegradable products, such as fats and grease, or roots. Another common blockage in lateral lines is from mud and sediments after a heavy rain where a septic system can overflow. Also, if the lines were installed poorly, the entire system could fail. Backups from a clogged lateral line can quickly become a health hazard, not to mention the exposure to both odorless, colorless septic fumes.