Septic tanks are great for single family-dwellings, awful for dense apartment buildings, and scale from great -> awful very quickly in between. IOW, wastewater

Septic tanks are great for single family-dwellings, awful for dense apartment buildings, and scale from great -> awful very quickly in between. IOW, wastewater infrastructure is necessary above a certain density. The irony is that wastewater infrastructure is one of the areas where cities often defer maintenance, leading to sewage backups when it rains.