Septic tanks and small sewage treatment plants
Septic tanks and treatment plants: permits and general binding rules. Guidance for owners or contact the Environment Agency for advice.
If your house or business is not connected to the mains sewer, your sewage will go to one of the following:
- a septic tank - an underground tank where the solids sink to the bottom and the liquid flows out and soaks through the ground
- a small sewage treatment plant (also known as a package treatment plant) - a part-mechanical system that treats the liquid so it's clean enough to go into a river or stream
- a cesspool (also called a cesspit) - a sealed tank that collects the sewage
- a non-standard system, such as a reed bed or trench arch system
Emptying a septic tank
We no longer operate a septic tank emptying service.
If you need to have a septic tank or cesspool emptied you will need to contact a private contractor.
Registration of a septic tank or small sewage treatment plant
As the 'operator' of a septic tank or small sewage treatment plant you must check you meet the general binding rules. You must apply for a permit on GOV.UK if you do not.
There is information about the general binding rules on GOV.UK.
You're an operator if any of the following is true:
- you own the property that uses the system
- you own a property that shares the system with other properties - each property owner is an operator, and you're jointly responsible for complying with the general binding rules
- you have a written agreement with the property owner that says you're responsible for the system's maintenance, for example you're renting and it's in your tenancy agreement
Contact the Environment Agency if you're not sure whether you're an operator.
If you have a non-standard system
You must contact the Environment Agency to find out if you need a permit.
General advice to householders
General guidance for the owners of septic tanks.
Understand how your system works
Most systems involve settlement by gravity, the action of micro-organisms and dispersion of the effluent into the sub-soil.
Locate all manholes, pipes and tanks
Knowing where everything is within your garden will help you to avoid damaging pipe work and will make you emptying and cleaning the tank easier.
Check the level of sludge at regular intervals
At least three times a year you should dip the tank to check the level of sludge in the chambers. If this gets into the sub-soil drains they will loose their porosity.
Arrange emptying of the sludge often enough to prevent damage to the land drainage system
You should determine emptying frequency on sludge levels and not on whether the system is blocked and unable to work. Once the sludge has entered and land drains it is very difficult to regain their porosity. It is recommended that tanks are emptied at least annually.
Prevent unnecessary surface water gaining access to the system
Divert any rain water into a separate soakaway or ditch as this clean water requires no treatment and may overload the system. Check the walls of the tank during emptying for ground water penetration and carry out remedial works if required.
Keep harmful chemicals out of the system as far as possible
The bacteria in your tank are helping to purify the sewage and if they are killed be excessive use of bleach or other bactericides the system will break down. Keep the use of detergents to a minimum as these chemicals impair the sedimentation process.
Consider the affects on the system from any alterations to your premises
Additional sanitary fitments, washing machines and dishwashers will inevitably result in extra sludge and in turn to more frequent emptying. Extensions, garages etc must not prevent the emptying tanker getting to within 200 feet on the system.