Septic tank
While a properly maintained and located septic tank does not pose any more environmental problems than centralized municipal sewage treatment, certain problems can arise with septic tanks in unsuitable locations. Since septic systems require large drainfields, they are not suitable for densely built areas.
Cesspit
In the UK a cesspit is a sealed tank for the reception and temporary storage of sewage; in North America this is simply referred to as a "holding tank". Because it is sealed, the tank must be emptied frequently — in many cases as often as weekly. Because of the need for frequent emptying, the cost of maintenance of a cesspit can be very high.