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If you lived or worked in a rural property not connected to the mains sewage system, chances are you are well-versed in the world of cesspools, cesspits and septic tanks.
But for those who have always had drainage that connected straight into the sewers, these systems can be rather confusing. The terms are often used interchangeably when often they shouldn’t be.
Knowing the difference is crucial for maintenance, compliance, cost and functionality. In this guide below we will help you understand exactly that.
Cesspits and Cesspools
Cesspits and cesspools are used interchangeably, and that is ok. They’re the same thing; an underground tank that simply stores sewage until it is emptied by a tanker. Neither a cesspit or a cesspool will treat the waste that it collects, and there is no outflow.
Depending on usage, cesspits and cesspools need to be emptied regularly, as the waste is collected and not discharged anywhere. Whilst both systems are legal in England and Wales, both are heavily regulated. In Scotland, cesspools are illegal due to environmental concerns of leakage.
If your property has a cesspool, you must ensure that it is emptied regularly by a registered waste carrier, and ensure that the system does not leak or overflow. Official guidance from the gov.uk website is that “you do not need a permit unless the Environment Agency tells you that you do”.
If your system releases sewage in any format, either into the ground or surface water, then it is not a cesspool. If your cesspool causes pollution or leaks, you are breaking the law and risk punishment. The local council or Environment Agency can make you repair or replace the cesspool if it falls into a state of disrepair.
If you are unsure what type of system you have, contact a local specialist liquid waste management company like Peachy Services and we will be happy to help you find out.
Installing a new cesspool
If you are looking to install a new cesspool on your property, there are certain rules you must follow, including:
- Obtaining planning permission and building regulations approval.
- Ensure it has a minimum capacity of 18,000 litres per 2 users, with another 6,800 litres per each extra user.
If you have a cesspool then you’ll likely be interested in reading our informative guide on how to tell if your cesspool is full?
Septic Tanks
Septic tanks are different from cesspits and cesspools, as they partially treat the sewage and waste through natural bacterial processes.
The liquid waste, known as effluent, will then drain into a soakaway or drainage field. Whilst the liquid waste will be drained away, solid waste will remain which will need to be emptied.
However, the frequency of emptying septic tanks is significantly lower than the need to empty cesspits and pools. Check out our detailed piece on just how often septic tanks should be emptied.
Installing a septic tank
All septic tank installations in the UK must meet the UK standards, known as the General Binding Rules. These rules apply to those who are responsible for either:
- Septic tanks
- Sewage treatment plants
As long as you abide by the general binding rules, you will not need a permit. The rules vary depending on whether you discharge to surface water or the ground.
Discharging to surface water
As of January 2020, septic tanks can not discharge into surface water, such as rivers, streams and ditches.
Owners of septic tanks that discharge into the surface water must by law upgrade the system when either selling the property, or if the Environment Agency identifies a pollution problem. You can voluntarily upgrade your septic tank at any time.
Septic tanks that discharge to surface waters should be upgraded to a sewage treatment plant, which treats waste to a higher standard, or redirect the discharge to a soakaway or drainage field.
The full general binding rules for small sewage discharge systems cover 23 separate rules, although not all rules apply to all systems.
General binding rules
The following general binding rules apply to all small sewage discharges:
| Rule Number | Discharges to Surface Water | Discharges to Ground | General Binding Rule |
|---|---|---|---|
| 1 | No | Yes | The discharge must be 2 cubic metres or less per day in volume. |
| 2 | Yes | No | The discharge must be 5 cubic metres or less per day in volume. |
| 3 | Yes | Yes | The sewage must only be domestic. |
| 4 | Yes | Yes | The discharge must not cause pollution of surface water or groundwater. |
| 5 | No | Yes | The sewage must receive treatment from a septic tank and infiltration system (drainage field) or sewage treatment plant and infiltration system. |
| 6 | Yes | No | The sewage must receive treatment from a sewage treatment plant. |
| 7 | No | Yes | The discharge must not be within a groundwater source protection zone 1 or within 50 metres from any well, spring or borehole that is used to supply water for domestic or food production purposes. |
| 8 | Yes | No | For discharges in tidal waters, the discharge outlet must be below the mean spring low water mark. |
| 9 | Yes | Yes | All works and equipment used for the treatment of sewage effluent and its discharge must comply with the relevant design and manufacturing standards, meaning the British Standard that was in force at the time of the installation, and guidance issued by the appropriate authority on the capacity and installation of the equipment. |
| 10 | Yes | Yes | The system must be installed and operated in accordance with the manufacturer’s specification. |
| 11 | Yes | Yes | Maintenance must be undertaken by someone who is competent. |
| 12 | Yes | Yes | Waste sludge from the system must be safely disposed of by an authorised person. |
| 13 | Yes | Yes | If a property is sold, the operator must give the new operator a written notice stating that a small sewage discharge is being carried out, and giving a description of the waste water system and its maintenance requirements. |
| 14 | Yes | Yes | The operator must ensure the system is appropriately decommissioned where it ceases to be in operation so that there is no risk of pollutants or polluting matter entering groundwater, inland fresh waters or coastal waters. |
For a discharge that was started on or after 1 January 2015, the following general binding rules also apply:
| Rule number | Discharges to Surface Water | Discharges to Ground | General Binding Rule |
|---|---|---|---|
| 15 | Yes | Yes | Discharges must not be within 30 metres of a public foul sewer. |
| 16 | Yes | Yes | For discharges, the operator must ensure that the necessary planning and building control approvals for the treatment system are in place. |
| 17 | Yes | No | Discharges must not be in or within: 500 metres of a Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar site, biological Site of Special Scientific Interest (SSSI), freshwater pearl mussel population, designated bathing water, or protected shellfish water; 200 metres of an aquatic local nature reserve; 50 metres of a chalk river or aquatic local wildlife site. |
| 18 | No | Yes | Discharges must not be in, or within 50 metres of, a Special Area of Conservation (SAC), Special Protection Area (SPA), Ramsar site, or biological Site of Special Scientific Interest (SSSI), and must not be in an Ancient Woodland. |
| 19 | Yes | No | Discharges must be made to a watercourse that normally has flow throughout the year. |
| 20 | Yes | No | For discharges, any partial drainage field must be installed within 10 metres of the bank side of the watercourse. |
| 21 | Yes | No | Discharges must not be made to an enclosed lake or pond. |
For a new discharge that started on or after 2 October 2023, the following two general binding rules also apply:
| Rule Number | Discharges to Surface Water | Discharges to Ground | General Binding Rule |
|---|---|---|---|
| 22 | Yes | Yes | A new discharge shall not use the same outlet as any other discharge if the combined volume of those discharges would exceed the volumetric general binding rules thresholds for groundwater or surface water. |
| 23 | Yes | No | A new discharge shall not be made to a discharge point within 50 metres of any other exempt groundwater activity or water discharge activity. |
Source: gov.uk
Choosing which system is right for you
If you are considering installing a new drainage system not connected to the mains, there are a few important considerations before choosing a cesspool, pit or septic tank.
Peachy Services are experts in all things drainage and waste management, for residential and commercial properties across the South of England. If you need some advice or guidance, or are ready to get your new system installed, contact us so we can help.
