A standard DWG misses this – but you must add it. Look for a note specifying at the cold joint between the floor and walls. If the drawing lacks this, download a separate "waterstop detail" and overlay it. A septic tank that leaks effluent is an environmental violation.

[Insert download link]

: A comprehensive resource for architectural CAD details, featuring manufacturer-specific septic tank templates, effluent filters, and accessories.

Many municipal environmental departments provide "standard drawings" that are pre-approved for local use.