In Hawaii, there are typically three main types of sewer systems used for wastewater management: county sewer, individual septic systems, and cesspools. Septic is an on-site sewage treatment and disposal system in the ground with a septic tank and a soil absorption area, commonly found in rural areas. Organic solid material, or scum, floats to the surface and is converted to a liquid by the bacteria. Inorganic material, or sludge, and the byproducts of the bacterial digestion sink to the bottom of the tank. Only clear water is to overflow into the absorption area. You should avoid allowing the following to enter the septic system as it will harm the bacteria: acids, bleaches, caustic drain openers, cleaning compounds, detergents, disinfectants, polishes, and toilet cleaners. Accumulated sludge and scum should be removed regularly. Cesspools, also known as leaching pools, are large pits in the ground encased within either cement block, brick, or concrete. Wastewater enters the cesspool and drains through the perforated walls into the surrounding soil, leaving the solids in the pool. Cesspools risk contaminating ground water, reason the state banned new installations of such since 1991.