Septic tanks can provide an economic and reliable solution for homes without mains drainage. They are available in a number of shapes and sizes depending on customer requirements, catering for everything from single dwellings to large residential developments. Septic tanks have proven reliability with no moving internal parts and have low installation and maintenance costs. Septic tanks are separation systems, where raw sewage enters and settle by gravity to the bottom of the tank where they are exposed to naturally occurring anaerobic digestion then flow through baffle arrangements providing further clarification, then the partially treated effluent flows into a percolation area or filter bed system for final "cleaning". However, although they are low maintenance, they are not no maintenance! At the very least they require any sludges built up in the base of the septic tank to be emptied annually.
Septic tanks are a proven method of dealing with sewage but are not suitable for every situation, for example if soil condition is poor, the building is in close proximity to a watercourse or there are building regulations in force which prohibit the use of a septic tank. Septic tanks are often traditionally built tanks from either brick or concrete and all septic tanks are designed to promote the growth of anaerobic micro-organisms which partially degrade the sewage and wastewater. Septic tank installation costs average around £1300 but will of course vary depending on the size and site requirements.
The anaerobic digestion process within a septic tank which reduces sludge volume can release methane, hydrogen sulphide and other gases which in some cases cause a serious odour nuisance! Septic tanks need to be correctly vented to allow gases to escape to the atmosphere. The effluent from a septic tank is disposed of to a soakaway and does not simply discharge to a ditch or stream, which is an offence under the Public Health and Water Resources Acts!
However older septic tanks often do discharge directly to ditches and streams as they have been installed in areas where the ground conditions do not favour a soakaway system, or the tank is full, blocked or leaking. If a septic tank id found to be discharging into a ditch or stream, it requires either a Permit or Exemption Certificate from the Environment Agency.
Septic tank failure can result in effluent surfacing on your land, bad odours coming from the septic tank or drains, pollution of nearby ditches or streams, slow flushing of toilets, gurgling in the drains, ground movement near the septic tank or soakaway, toilets overflowing, overflow at washing machine hookup, shower or bath.
The most common causes of septic tank failure are internal baffle collapse resulting in solids and floating material passing through the tank and into the soakaway network, rupture of prefabricated tanks if not installed using the correct backfill material, dip pipes falling away from the inlet or outlet pipes, cracking of concrete tanks allowing ground water ingress or the mortar joints on brick tanks suffering from sulphate corrosion causing cracking in mortar joints. All Septic tanks should be water tight, ground or surface water entering into a tank can cause flooding and failing of the soakaway.
Regular servicing is required to ensure long service life of your sewage treatment system. Each year pumps should be removed, checked and cleaned; condition of pipework should be checked, distributors should be stripped down and checked, diaphragms and filters checked and/or replaced, pumps should be tested under working conditions, floats and/or high level alarms to be checked and desludging or cleaning to be carried out as required. It costs around £150.00 to empty a septic tank.
Quickly gather quotes from local drainage specialists in your area using the free quote service on this site, then, once you have 3 or more drainage companies get in touch with prices and advice, ensure that the contractor you choose has liability insurance and make sure any maintenance contract lists the specifics of your job, check that clean-up and debris removal is part of the contract and check any follow-up or guarantees the contractor provides.
If installing a new septic tank system make sure that the contractor obtains any necessary building permits and is aware of any underground utilities in the area. Be wary of any company insisting on cash payments, particularly advance payments, most contractors will be happy to be paid when work is complete, or operate on a staged payment system for larger contracts.Also note that if your home has a septic tank or a small sewage treatment plant, you have to register this with the Environment Agency or with Natural Resources Wales.