If there is a sewer available, but at a higher level, it may be worth considering installation of a sewage pumping station and rising main. These are usually relatively small tanks fitted with one or two submersible pumps, designed either to pass solids up to a certain size (solids-handling) or chop them up (macerators/grinders/cutters). Solids-handling pumps tend to be cheaper and more reliable - but require larger diameter pipework.

Macerators/grinders/cutters can generally pump higher/further, through a smaller, more flexible rising main.

A septic tank usually has two compartments and is designed to retain solids whilst allowing the liquid content to be discharged. These solids partially decompose, producing a ‘sludge’ that needs to be removed by tanker vehicle, usually once a year.

Unfortunately effluent quality is very poor and only suitable for discharge into land, via a sub-surface irrigation system or soakaway. A septic tank is usually the most economical means of private drainage, but its use is dependant on both ground conditions and the level of the water table. It is therefore essential that a percolation test is undertaken in accordance with that specified in British Standard BS6297:1983 before proceeding further.

Sewage treatment plants are generally used where septic tank drainage is inappropriate and are designed to produce an effluent to comply with Environment Agency requirements for discharge to a watercourse.

Modern ‘packaged sewage treatment plants’ are usually made of GRP (fibreglass) or polyethylene and are internally divided to provide separate compartments for primary settlement, biological oxidation and secondary settlement, which reduces the polluting material by approximately 95%. As the term implies, biological oxidation requires the presence of oxygen (from air), which can be provided by a number of means, but all ‘package’ plants use electricity, need de-sludging at regular intervals and require some degree of maintenance.

A more detailed explanation of the sewage treatment process is included elsewhere on the site.

A cesspool is a sealed underground tank where sewage is stored until emptied by a tanker vehicle. Building Regulations require a cesspool serving a residential property to have a minimum capacity of 18,000 litres (4,000 gallons) for two users, which should be increased by a further 6,800 litres (1,500 gallons) for each additional user.

Typically, a tank serving a family of four is likely to need one tanker load removed every two weeks or so, to prevent it from overflowing. This makes a cesspool the most expensive option for domestic use and is only recommended as a last resort.