Buying a Property with a Septic Tank

When buying a property, it is important to make sure you have done your due diligence with regard to the current condition and maintenance requirements of the premises. If you are buying a property with a septic tank, understanding how this system works is a key part of this process.


Because septic tanks are hidden underground, they can be easy to overlook, but it is important not to do so in order to keep on top of your new property’s maintenance and upkeep. This is especially crucial if you have never previously owned an off-mains drainage system, and do not already know how they work.


Here, we will look at some of the key responsibilities you will need to be aware of when purchasing a property with a septic tank or another form of off-mains drainage, as well as the key questions you should ask during the buying process.

What are your responsibilities when buying a property with off-mains drainage?

An off-mains drainage system is an appliance for homes that are not connected to the main sewage network, used to store, filter or treat the property’s wastewater and sewage output. Septic tanks are the most common type of off-mains drainage, but this category can also include sewage treatment plants and cesspits.


If your new property has a septic tank or similar system, you will have a number of requirements and responsibilities that you will now need to fulfil:



  • Ensuring your drainage system is kept in good condition, without causing pollution or environmental damage

  • Maintaining the system in line with all of the relevant regulations (you can find out more about these regulations here)

  • Making sure the system is emptied regularly to avoid overflowing – this should be done around once a year for septic tanks and sewage treatment plants, and once every one or two months for cesspits

  • Servicing the tank regularly to check for underlying issues, usually around once a year.

What information should you expect to receive about your new septic tank?

In order to fulfil these responsibilities, you will need to make sure that you have received all of the necessary information from the seller on how the system works, and what its maintenance requirements may be.


The seller has a legal obligation to provide the following pieces of information during the sales process:



  • A full description of the drainage and treatment system, including the location of the treatment system, drainage system and discharge point

  • Complete maintenance and emptying records for the system

  • Details of how the system should be maintained, including any relevant manuals and official documentation

  • Information on any changes that have been made to the system


All of this information needs to be provided to you in writing, so you should make sure that you have received this before the sales process concludes.

What questions should you ask about your septic tank?

In addition to the legally required data above, it is a good idea to speak to the seller to get as much additional information as possible on how the system works. As such, it is recommended to ask the following questions:



  • Has the tank been emptied in a regular and timely manner by the previous owner? When was the last time it was emptied?

  • Have there been any problems with the drainage system in the past? Is the system currently in good condition, or are there existing problems that need to be taken care of?

  • Is the drainage system shared with any other local properties? If so, are there any agreements in place regarding the maintenance and repair of the system?

  • Does any part of the drainage system lie outside of the boundaries of the property? What is the arrangement for accessing these, if repairs or maintenance are required?


By asking the right questions, you will be able to ensure that you have all the information you need to keep your new off-mains drainage system in good working order for many years to come.

How can I check for problems with my septic tank?

Even with all of the necessary due diligence done, you may still encounter a problem with your new septic tank shortly after purchasing a property. The following signs may be indicators that the system is not working as it should be:



  • Gurgling sounds coming from the pipes and plugholes

  • Sinks draining slowly, or water and sewage backing up from drains, sinks and toilets

  • Foul odours around the septic tank, drainage field and/or soakaway

  • Damp spots or standing water near to the septic tank

  • Unusually bright and lush grass growing around the septic tank area


If you suspect a problem with your new drainage system or simply wish to carry out a thorough check of its current condition after purchasing a property, get in touch with Lanes to organise a comprehensive homebuyers’ drain survey. Using CCTV surveying technology, we can assess your entire drainage system to look for signs of damage to your septic tank and pipes, as well as other common drainage-related problems.


To find out more about this service, visit our homebuyers’ drain survey page. For a free quotation, call us on 0800 526 488 or use our online enquiry form.

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