You must have a product adapted for the size of your house, so your sewage treatment must have enough capacity to handle the maximum amount of wastewater that your home will produce.
For example: If your house has the capacity for five individuals (PE 5), you will have to install a suitable sewage treatment system which can cater to this volume.
You can find guidance on how you choose your tank size in relation to usage capacity within this BCA PDF document: Guidance on sizing of Package Sewage Treatment Plants
*For further details and other information please consult: British Water’s Flows and Loads 4 guidance.
If you decide to upgrade your current system, you will need then to follow the sizing requirements outlined by the British Water’s Flows and Loads 4 guidance documents (link above).
For example, if you want to extend your property (add more rooms or connect another house), you will have to check if your sewage system can handle the extra load as a result of the extension. If the data states that it will not, you will have to upgrade your system. You will have to maintain your system.
All sewage systems require yearly maintenance in order to protect both the product and the environment, this is essential. If you own a sewage treatment system, you will need to get it serviced and desludged by a professional in-line with the manufacturers guidance and advice.
The sludge removed must be taken and disposed of by a registered professional.