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 Do I have a Cesspit?


Many of the people that contact WCI about a home buyers drainage survey, the Environment Agency’s 2020 General Binding Rules or the legal compliance of their private, off mains drainage system, often describe their foul drainage system as a ‘cesspit’.

If you research the word ‘cesspit’ in Wikipedia it states that ‘A cesspit (or cesspool or soak pit in some contexts), is a term with various meanings: it is used to describe either an underground holding tank (sealed at the bottom) or a soak pit (not sealed at the bottom).[1] It can be used for the temporary collection and storage of faeces, excreta or faecal sludge as part of an off mains private sewage treatment system and has some similarities with septic tanks or with soak pits. Traditionally, it was a deep cylindrical chamber dug into the earth, having approximate dimensions of 1 metre diameter and 2–3 metres depth. Their appearance was similar to that of a hand-dug water well’.

If you ask most people in the West Country what a cesspit is, you will actually find they are referring to a septic tank. Like the generic words ‘klargester’ or ‘digester’ that are used to describe a sewage treatment plant, the word cesspit is a generic word often used to describe a septic tank.


So how do you find out what foul drainage system serves a property?


Start by asking the following questions about the system:


1. How often do you empty your system?

Now this can be a red herring. I still come across people that have never emptied their tank in the 40 years of living at a property. But on the whole, if you empty your system every 1-3 years, then you have a septic tank. If you are emptying weekly or monthly then it is a cesspool (or a failed septic tank system!!).

2. Does your tank have an outlet? Does it drain into a soakaway, clinker bed, drainage field, herring bone, ditch or watercourse?

Most people know, or have an inkling, what happens after the septic tank. If your tank has an outlet then it is a septic tank. You can ask the owner to check the property deeds. Some properties have drainage diagrams or descriptions which can shed light on the question.

3. By checking the last waste transfer notice given to you by your licensed septic tank emptying company. How much liquid was taken away?

Typically, a domestic septic tank (serving up to a 12 bedroom property or 2 x 5 bedroom properties) will be under 1,000 gallons or 4,500 litres capacity. In current Building Regulations, the capacity of a cesspool starts at 4,000 gallons or 18,200 litres for 2 people.


Still none the wiser?


Then I would suggest booking a WCI Engineer to come to site, survey the system and carry out a Home Buyers Drainage Survey. At the end of the survey, you will not only know what system serves the property but also if it is fit for purpose and conforms to current Building Regulations and Environment Agency standards.

Please note that the Environment Agency 2020 regulations state that if a property’s septic tank discharges to a watercourse (ditch, stream, rhyne or river) and not a secondary form of treatment (most commonly a soakaway or drainage field), it is illegal and must be replaced or upgraded by the 1st January 2020. Please note this continues to be the law now we have passed 1st January 2020. If you are buying or selling a property with a septic tank that discharges directly to a watercourse, you should agree with the buyer or seller who will be responsible for the replacement or upgrade of the existing treatment system. You should agree this as a condition of sale.


Please call us on 01984 623404 or get in touch via the Contact Form to talk to us about our Home Buyer’s Drainage Surveys.