A septic system in Ontario requires repair or replacement when it exhibits signs of failure such as sewage backing up into the home, pooling water in the drain field, or unusually lush grass over the drain field.

The Ontario Building Code (OBC) governs all septic system work, including significant repairs, alterations, and replacements, and often requires permits and the involvement of licensed professionals. Homeowners are responsible for maintaining their septic systems to protect public health and the environment.

Tertiary treatment’s main advantage is its ability to significantly improve water quality by removing remaining contaminants - including nutrients, pathogens, and fine particulates - after primary and secondary treatment stages, making the treated water suitable for safe discharge or reuse.