Buying A House With A Septic Tank

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Most homeowners in the UK don’t have to think about where their waste is going as they are connected to the mains drainage system. However, this is not the case for every property. The small percentage of properties that do not fit into this category will have self-contained waste disposals such as a septic tank, or cesspit. Buying a house with a septic tank is generally seen as a favourable way to live in a property that is not connected to the main drainage system.

In this article, we will be looking at the differences between a septic tank and a cesspit, the pros and cons of a septic tank, and what you need to consider before buying a property with a septic tank.

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What Are The Types Of Mains Solutions?

There are two main types of waste disposal, septic tanks, and cesspits. There are similarities and differences between the two units. Whilst both are tanks that are buried beneath the surface, septic tanks are self-emptying whereas cesspits require manual emptying around once a month depending on how many people are using them.

A septic tank works by dividing wastes and solids so that they can be discretely disposed of. A cesspit on the other hand holds the waste until it is collected by a liquid waste disposal company.

Septic Tank vs Cesspit

Septic Tank:

A septic tank is a more favourable way to live in a property that is not connected to the main drainage system. A septic tank is a wastewater treatment option that collects the effluent and using a dividing door separates the substances and allows the liquid waste to pass through whilst stopping the solid.

Once it has been treated, the wastewater can drain away into a stream or a soakaway system. A soakaway is a form of basic drainage system that is made by digging a hole in the ground and filling it with stones and rubble. This allows the treated water to drain away whilst retaining any solids.

Since January 2020, surface water has become illegal and septic tanks are no longer allowed to discharge it.

Treatment of the septic tanks waste can only happen if the drainage field is constructed properly. The owner’s responsibility is to ensure that the drainage field is constructed and is working in line with the General Binding Rules.

Whilst a septic tank does not need as much upkeep as a cesspit, it is still advised that it should be recurrently checked out by a licensed liquid waste disposal professional.

The way a septic tank works is the waste that cannot drain away is broken down by bacteria. As it is a biologically friendly option, it is not recommended to use strong chemical cleaning products as this can disrupt the natural order.


Another option that is used by those with properties that are disconnected from the main sewage works is a cesspit. Whilst a cesspit is a very different waste disposal option from a septic tank, the two are often confused.

Much like a septic tank, a cesspit is buried beneath the surface, however, unlike its counterpart the septic tank, it is not a treatment option. A cesspit serves as a holding tank without an outlet and as it does not treat and then filter out the waste, a cesspit needs to be regularly emptied about once a month by a licensed liquid waste professional so that it does not overflow.

Because of this, cesspits require a great deal of maintenance and are illegal in Scotland. Whilst cesspits are legal in England, it is the owner’s responsibility to make sure they are properly maintained. Should the cesspit be damaged, overflowing, or leaking, the Environment Agency will fine any property owner with a cesspit they find to be faulty.

Out of the waste disposal options, a cesspit is rarely anyone’s first choice. Most properties tend to favour the septic tank as it is the cheaper option with much less upkeep involved.

A cesspit is usually installed if the ground around the property has failed the soakaway test and you don’t have a watercourse or surface water drain that the sewage can be deposited into.

They are usually used as a temporary solution for waste disposal, such as on a campsite or construction site.

What To Know If You Are Moving Into A House With A Septic Tank?

Buying a house with a septic tank presents its own unique set of challenges, to get the most out of your new home and septic tank, you should ask the current owners plenty of questions so you know exactly what you are getting yourself into.

By law, the current owners of the property are legally required to provide the following information:

  • Where the drainage is system is located
  • Maintenance and emptying of records
  • A description of the treatment system and drainage system
  • Details of how the system should be maintained and a maintenance manual
  • Details of any changes made to the system

To avoid any nasty surprises or costly mistakes, here are some things to consider and ask current owners:

  • How often do the current owners empty the tank?
  • How much does the tank cost to empty regularly? Can the current owners give you a guide as to what they pay locally?
  • Is the septic tank shared with other properties? If this is the case, what are the agreements in place around the maintenance and repair of the system? What is the relationship like with the other property owners?
  • Is any part of the drainage system outside of the property’s boundaries? If so, what rights exist for access to maintain, repair or replace the system?
  • If the property field has a drainage field (a network of perforated or slotted pipes which allow wastewater to percolate safely into the ground), is there enough room for a replacement one if it fails? These cannot usually be repaired if they fail and they also can’t be replaced in situ.
  • What condition are the tank and the pipework in – are there any existing problems that need to be addressed? Remember, things may appear to be fine on the surface, but trouble underground can take time to manifest itself above ground.

Book A Home Buyer Drainage Survey

When buying a house with a septic tank, you should always book a home buyer drainage survey to determine if there are any issues with the drainage system. These surveys can help to highlight any common issues that may be lurking within the drainage system, such as defective pipes, blockages, tree root intrusions, and collapses.

Knowing everything about the septic tank on your property before you move in will help you be fully prepared for any eventuality. If these problems aren’t discovered, they may become a bigger issue and you’ll be left with costly repairs in the long run.

What Are The Pros And Cons Of A Septic Tank?

Before buying a house with a septic tank, it is important to weigh up the pros and the cons of the tank and what it will mean for you.


  • Durability – When a septic tank is properly maintained to a high standard, it can last for years and rarely need to be replaced.
  • Cost-Efficient – Extensive sewer lines that are found with properties that are on the mains grid are very expensive to build and maintain whereas a septic tank is cheaper to install and doesn’t come with monthly maintenance costs.
  • Environmentally friendly – Septic tanks do not contaminate the water supply as they remove bacteria from the water before it is released into the soil. The nutrients in the water can also help nearby plant life flourish.


  • Periodic Maintenance – Septic tanks need to be pumped every three to five years and it is the responsibility of the owner to organise it.
  • Backed Up Drains – Materials that shouldn’t be flushed or put down the drain can cause blockages and clog the septic lines. Signs of a backup include slow sink and tub draining, as well as slow flushing toilets. If you notice these, bring in a plumber to inspect the septic system.
  • Potential Ruptured Pipes – Pipe ruptures can be caused by a whole host of factors such as damage from tree roots, a vehicle rolling over it, an accident whilst digging, an earthquake, or any other reason. These ruptures can lead wastewater to leak into the soil, the ground will become soggy and you’ll likely notice a foul smell. The ruptured pipe will need to be replaced as soon as possible.

What Are The Costs Of Maintaining A Septic Tank?

To have a septic tank cleaned and emptied professionally, the average tradesperson will normally charge around £200, however, this can vary based on the size, scale, and time it would take to clean your tank.

There are also many factors to consider when budgeting to have your septic tank professionally cleaned, such as the type of septic tank that you own and how easy it is to gain access to the tank.

Whilst a septic tank needs emptying and cleaning, it is not just a one-off treatment. In order to properly look after your septic tank, it needs to be frequently maintained around twice a year, depending on the volume of waste your household accumulates.

How will owning a septic tank affect me?

Owning a home with a septic tank will mean that instead of being connected to the main drainage system you are living off the grid. Whilst for the most part it won’t be any different from living in a home that is connected, there are certain things you will need to consider and rules and regulations you will need to be wary of.

As the owner of a property with a septic tank, you will be responsible for ensuring the system is compliant with the General Binding Rules. You will need to arrange an annual inspection, service, and empty to ensure it is well maintained.

This concludes everything you need to know about buying a house with a septic tank and all that it involves. If you have any questions or queries, or any experience with septic tanks, please feel free to get in touch!

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photo of Alexandra Ventress

Alexandra is a junior content producer who enjoys writing articles and finding out more about the property market. Read more about Alexandra here.

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About Alexandra Ventress 91 Articles
Alexandra is a junior content producer who enjoys writing articles and finding out more about the property market. Read more about Alexandra here.

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