Some people when they purchase a property in Spain are not aware that they may have a septic tank or cesspit, but it is quite common for older rural properties to have one or the other. Since Spain joined the EU there has been a vast quantity of money spent on new sewerage treatment plants, however there are plenty of properties that will never be connected because it would not be viable. It is in these cases that a cesspit or a septic tank will be used.

The most important thing is to be informed as new EU legislation means that some of the older systems will not be acceptable any longer, this is fine if you have already got one but if you are planning an upgrade or a new build then you need to know there are new efficient systems available.

A cesspit is an underground holding tank used to store the waste from your home that would normally go straight in to the mains sewer. The cesspit does nothing more than store the waste until the tank is full and then it will need emptying. A cesspit will be built from bricks or concrete blocks and rendered or from caste concrete. It is important that it is totally watertight so as not to let any of the waste leak into the surrounding soil or water source.

The time between emptying depends on the usage and size of the tank. Some tanks may be quite small though, as they were built only for small usage and only hold a couple of thousand litres whilst others could hold as much as 15,000 litres. The average person is said to use between 60 and 100 litres per day so a small tank could fill up quite quickly so it could be that a small tank would need emptying every couple of months and a large one every 6 or so months. Be aware though because if you think your tank does not need emptying very often it could be because your cesspit leaks! We have this type of holding tank in concrete its a very large one, not sure how many litres but we empty yearly and we ahve lots of guests!!! costs us around 70 euros to get this cleaned and emptied, when we were green from the smell as well as green from inexperience it first cost us over 200 euros! So shope around.

Very different to a cesspit a septic tank is a basic mini sewerage-treatment plant designed for single properties or small developments. A septic tank provides a permanent solution for waste and requires only periodic emptying and maintenance. Many older Septic tanks are made of concrete or pre-caste concrete however the modern ones are made of plastic which is reinforced.

The Septic tank is generally divided into two chambers which reduces the flow of water from inlet to outlet allowing for separation and settlement to occur and for the bacteria present to break down the waste. The first chamber receives the main drainage pipe form the property. This is where the waste is separated form the liquid and settles to the bottom while the water is pushed through into the second tank. Here any excess floating particles settle in the bottom of the tank and the liquid is passed into what’s called a soak away or drainage channels which are below the ground.

The inlet and outlet pipes within the chambers are made from T sections with the openings submerged below the water level. This stops the scum, which floats to the top of the liquid passing into the soak away.

An anaerobic bacterium (Obviously a very fit bacteria hence the name) turns the waste into a sludge which does need periodic removal from the tank. Six months to a year depending again on size and usage although every two years is not unusual, if the tank is working efficiently.

You can buy special products that help the tanks to work more efficiently.