Should You Buy A House With A Septic Tank In The UK?

Should You Buy A House With A Septic Tank In The UK?
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If you’re looking to buy a property that’s a little more rural, you may have to make the decision whether you are happy to buy a house with a septic tank or not.

In fact, the dream of living a little more remote often comes with a number of compromises to consider. A septic tank is one of the most common compromises you may encounter in the UK.

So, should you buy a house with a septic tank in the UK? The answer will depend on how much compromise you’re willing to make.

Having recently moved to a rural location ourselves, we have experience of buying a house with a septic tank and living with it. With our help, you can at least attempt to answer the question armed with all the information you require…

What Is A Septic Tank?

Let’s get the obvious question out of the way first. What is a septic tank?

If we check the dictionary, we get the following definition:

A tank, typically underground, in which sewage is collected and allowed to decompose through bacterial activity before draining by means of a soakaway.

So, it’s a method used to dispose of sewage when a property is not connected to the main sewage system.

Butler & Payne (1995) mentioned that septic tanks were first introduced to England in 1895. They have since then continued to elevate the standard living conditions of every household.

Note that while we are focused on ‘septic tank’, many modern septic tanks are actually ‘sewage treatment plants’. The main difference is that sewage treatment plants make the water safe enough to drain into nearby watercourses, whereas a septic tank does not.

In both cases, the tank will need emptying from time to time and they are both typically made of concrete, fibreglass or plastic and are usually buried out of sight.

It has an inlet through which waste from the toilets of the property enter, and an outlet through which the ‘treated’ water can drain away.

For the rest of this article, we’ll use the term ‘septic tank’ to refer to both septic tanks and sewage treatment plants.

We have a modern sewage treatment plant buried in the ground just behind our house and is near to a drainage ditch. While it’s not technically on our land, we have a legal agreement in place for access to the tank (e.g. to service or empty it).

Note that there are no chemicals involved in septic tanks, the water is simply ‘cleaned’ through a process of settling and anaerobic processes. A septic tank will need emptying periodically.

Please be aware: You need to follow the rules that are in place to prevent pollution from your system, or you could face penalties (or worse).

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Living With A Septic Tank In The UK

In the UK, living with a septic tank should not mean that you need to make any major changes to your lifestyle.

You can still use the toilet as normal, though you’ll need to be careful not to put items such as cotton buds, cigarette butts, condoms, etc down the toilet. That’s because such items are likely to cause blockages in the system if allowed to accumulate.

You’ll also need to avoid putting cooking oils down the sink or toilet and some cleaning products can also interfere with the natural process that takes place in a healthy septic tank.

We found that it can be a bit daunting at first, when you move into a home with a septic tank. You quickly get used to pouring any cooking oil into a glass jar or only putting toilet paper and the obvious down the sink.

But when it comes to cleaning products, it can be a bit of a minefield.

In our experience, most brands don’t bother mentioning if their products are safe to use with septic tanks. This can make finding the ones you can use quite difficult.

Inside our sewage treatment plant
Inside our sewage treatment plant

However, there are some that are out of bounds, such as laundry cleansers, because they are designed to kill bacteria.

This notion is supported by the findings of a pillar study by Gross (1987). It determined that common chemicals like liquid chlorine bleach, High Test Hypochlorite (HTH), Lysol disinfectant and Drano crystal all reduced bacterial population in septic tanks.

Because the septic tank uses certain bacteria, it’s important not to drain away anything that could harm them, as it would reduce its efficiency.

This means that anything that is designed to kill bacteria, such as bleach, should not be used with a septic tank.

The general rule is that most commonly used cleaning products are fine to use. However, we found that buying eco-friendly products that don’t contain harmful chemicals are the safest option. These also tend to tell you if they are safe to use with a septic tank.

While it can take a while until you have found products that you can use, we have found that you will soon get used to living with a septic tank. It becomes second nature, and you don’t even think about it anymore.

Apart from this, the only other thing you’ll need to be aware of is where your septic tank is located. That’s because you’ll need to monitor it for signs of damage or deterioration, you’ll need to avoid digging too close to the tank, and you’ll need access to the manhole occasionally for emptying.

What Maintenance Is Required?

Ceramic frog on the toilet

Providing a septic tank is properly maintained, it should last for at least 50 years.

Proper maintenance includes regularly emptying the tank. This will require the help of a specialist contractor.

How often the tank needs emptying depends on a variety of factors such as the capacity of your septic tank, and the volume of the liquids and solids in the wastewater flow (Walker, 2016).

In other words, it depends on both on its capacity and how often it is used, though once a year is not uncommon.

The instruction for our septic tank says to empty it every 6 months. But we found that we only have to empty our septic tank every 18-24 months. That’s because our private sewage treatment plant is designed for a family of four or five. Because there are only two of us, it takes much longer to fill it up.

The best way to find how often it will need emptying is by talking to the previous owners about it. That’s what we did. Of course, you still need to use common sense. If you buy the house from an elderly couple and move in with a family of three, this will change things.

But we found that you can check the inspection hatch of the septic tank to see if it needs emptying. If it needs emptying, you will see water. If you don’t see anything, you are fine to leave it.

Other than that, there are additives that can be added to the system to help keep things running smoothly. However, there is widespread disagreement over the usefulness of such products.

You perhaps, therefore, are best advised to simply empty your tank regularly and avoid placing foreign objects down the toilet. This may, in fact, be the only maintenance that’s required over the lifetime of the tank.

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Do New Houses Have Septic Tanks?

Most new houses that are built in groups, or which are in close proximity to other buildings, will not use septic tanks.

If a connection to the local sewerage system is possible, most property developers will do the work that’s required to avoid needing septic tanks.

However, a new build property is not immune from needing a septic tank. If it is located in a sparsely populated rural area, there is every chance that a septic tank will be the main sewerage system for the property.

When we were looking for our current home, we viewed a relatively new house. Because it was only built a few years previous, we assumed that it was connected to the local sewerage system.

However, because the house was quite remote, it actually had a septic tank. So we would recommend always asking, if you are looking at a more remote or rural property, even if it has been newly built.

To find out for sure, ask the person responsible for selling the property. A drainage and water search may also be useful to help you see how close the property is to an active sewer line.

Buying A House With A Shared Septic Tank

Shared Septic Tank

If you are buying a property with a septic tank that’s only used by the property in question and sits entirely on the property’s land, the process is relatively simple.

However, if you are buying a property with a shared septic tank, things get a little more complex.

This arrangement is usually more common in rural areas. Furthermore, Francis et al. (2019) found out that most households also prefer a shared septic tank as it was more affordable to maintain.

In such cases, there will usually be an agreement in place that outlines who is responsible for the maintenance of the tank and what costs are involved for everyone who uses it.

If such an agreement is already in place, you’ll need to be sure you’ve read and understood it. It would also be a good idea to ask your conveyancing solicitor to check over the wording of the document too.

If there is no existing agreement, your solicitor will probably advise that one is drafted up. This may delay the process of buying the property as you’ll need the document to be drafted and then agreed and signed by all parties it affects.

While we have a private septic tank that is only used by our home, the land where it is located is owned by our neighbours.

This added more complications to the buying process, because our solicitor had to check for any agreements that were in place.

Thankfully, there was a long-standing legally binding agreement already in place. We have the right of access and the neighbours have actually fenced it all off, so it looks like it’s part of our property.

All we have to do is to let them know when we need the septic tank emptying, so they can ensure that the horse that lives in the paddock next door isn’t in there.

Do You Need Planning Permission To Replace A Septic Tank?

The official guidance on this is a little vague. In most cases, only the installation of a new septic tank will require planning permission.

Simply replacing an old septic tank with a new one, with no significant changes to the location will not require planning permission in most cases. However, it can vary depending on which council the property falls under. You’re therefore advised to contact your local planning department for the avoidance of any doubt.

Replacing a septic tank with a connection to the local sewerage system is rarely an option but would require the approval of the water board before it can go ahead.

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Buying A House With A Septic Tank In The UK – What You Need To Know

If you are thinking of buying a property that does not have mains drainage, you should not be afraid, but you should be well-informed before you make an offer, especially if this is your first time buying such a property.

Here are some questions to ask and some factors to consider, to avoid any nasty and expensive surprises after you buy the property.

  • Have the current owners emptied the tank regularly?
  • How much do they usually pay to empty the tank?
  • Can they give you an idea of the local prices?
  • Do any other properties share the tank?
  • If yes, what are the arrangements for maintaining and fixing the system?
  • How do the current owners get along with the other property owners?
  • Is any part of the system outside the boundary of the property?
  • If yes, what are the rights for accessing, maintaining, fixing or replacing the system?
  • If the property has a drainage field (a series of pipes with holes or slots that let waste water soak safely into the ground), is there enough space for a new one if it fails? These usually cannot be fixed, and also cannot be replaced in the same place.
  • What is the state of the tank and the pipes – are there any problems that need to be solved? Remember, things may look fine on the surface, but trouble underground can take time to show up above ground.

Buying a property with off-mains drainage can be a rewarding experience, but it also comes with some responsibilities and challenges. You will need to ask the questions above and ensure your conveyancing solicitor is thorough.

You should also be aware of the costs and risks involved in maintaining and repairing the system, and plan accordingly.

By doing so, you can enjoy the benefits of living in a property that does not rely on mains drainage and avoid any potential problems in the future.

We thought we had been quite lucky when we bought our house with the septic tank, because the previous owners replaced it with a new one only three years before.

However, we’ve since discovered that the base of the tank wasn’t constructed correctly and the tank itself has actually sunk a little on one side. This caused the part that blows air in to the tank to maintain efficiency, to break off.

Our septic tank has sunk and twisted
Our septic tank has sunk in its foundations and twisted slightly

We’ve had to repair this unexpected problem ourselves and are continuing to monitor whether the tank is still sinking into the ground. So far it looks like it has settled and we won’t have a problem, but, if it does move further we may have to pay around £4000 to have the tank emptied, removed, and a more solid base put in.

So, our experience has shown that even when buying a house with a new septic tank, you can still run in to problems.

One plus of the tank being so new was that the sellers could give us all the relevant instructions, which was very helpful. At the same time, they gave us a crib sheet with any important information we might need, including how to check the inspection hatch.

This was very useful for us, as it was the first home we ever bought that had its private sewage treatment plant.

So, Should You Buy A House With A Septic Tank In The UK?

As you can see, there is no clear answer to the question of whether you should buy a house with a septic tank in the UK.

In most cases, we would say that if you have found your dream home, a septic tank should not stop you from going ahead.

Just be sure you do your research to find out the exact condition of the tank, how well it has been maintained, how regularly it will need emptying, and so on. This will help you to avoid any nasty surprises after you have moved in.

Of course, if after reading this article you still have doubts, a property with a septic tank may not be right for you. However, you may have to abandon any desires to live remotely if you want to be connected to a proper sewerage system.


  • Paul James

    Paul James, is a marketing expert with a passion for property. As well as being a property investor, Paul has also worked within the marketing departments of some of the UK’s leading estate agents. Paul is the founder of Property Road.

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