Septic tank
A septic tank is an underground chamber made of concrete, fiberglass or plastic through which domestic wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). Septic tank systems are a type of simple onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field which provides further treatment. However, groundwater pollution may occur and can be a problem.
Hot water storage tank
Some manufacturers offer an extended warranty kit that includes a replacement anode rod. Because conventional hot water storage tanks can be expected to leak every 5 to 15 years, high-quality installations will include, and most US building/plumbing codes now require, a shallow metal or plastic pan to collect the seepage when it occurs.