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.
Water supply and sanitation in the Philippines
In 2005 the situation was as follows: Only 5% of the total population was connected to a sewer network.The vast majority used flush toilets connected to septic tanks. Since sludge treatment and disposal facilities were rare, most effluents were discharged without treatment. Within the entire country, septic tanks are the most common method of sewage treatment. In Metro Manila alone, about 75 local companies provide tank-desludging services.