Selling a house with a septic tank

Living in the countryside is an idyllic dream for many people, but unfortunately, that dream comes at a cost. As many as half a million homes are not connected to the main sewers, and so they have to have a septic tank to collect their waste.

If this waste treatment system isn’t up to scratch, then it can make your property almost impossible to sell. Even if it is relatively new, many potential buyers can still be put off by the idea of a tank of human waste under their back lawn.

So how do you go about selling a house with a septic tank, and is it even possible if your tank is old and out of date? With a peg on our noses, let’s lift the lid on septic tanks and take a closer look inside.

Problems with selling a house with a septic tank

Having a tank full of human waste in close proximity to your property is not the ideal situation when it comes to selling it. Not only will some buyers be put off by the idea but it can also lead to added complications in the sales process.

If the septic tank hasn’t been updated recently then the chances are it might not comply with the regulations known as the General Binding Rules (GBR) which have been in force since January 2020. These rules mean that if the waste water discharge directly into surface water, such as a river, stream or pond you are in fact breaking the law.

Septic tank regulations in the UK 2024

Ironically, despite the fact that the water companies discharged raw sewage into our rivers and seas no less than 372,533 times in 2021 alone, the Environment Agency have a big problem with septic tanks discharging waste in the same way. In 2020, they introduced strict rules about the standard and quality of septic tanks in order to reduce environmental pollution (from individuals at least!).

Since 2020, the General Binding Rules have applied to all septic tanks and their discharge

As mentioned previously these new regulations are known as the General Binding Rules (GBR) and they banned the discharge of waste directly into a watercourse and set the standard for septic tanks and water treatment facilities. It’s no surprise that a large proportion of septic tanks, particularly older ones, didn’t meet these standards. Even today, despite being given a year’s grace to put things right, ending on 1st January 2021, a great deal of septic tanks are still the wrong side of legal.

Can you sell a house with an old septic tank?

If you have an outdated septic tank you can still sell your property but you will have to disclose the situation to any potential buyer and agree with them who will take on the responsibility for updating the system to comply with the regulations.

This means that one of you will be liable for the cost of the work. If it is you as the seller then you will have to stump up the cash and arrange for the work to be completed before the sale. If you agree that the buyer will pay then they will likely want the cost to be knocked off the asking price.

Can you get a mortgage on a house with a septic tank?

To make things even more complicated, even if you find a buyer who is happy to go ahead with buying your home with an old septic tank, chances are their mortgage lender won’t be. Most lenders will not offer a mortgage on a home with a septic tank unless it is Council of Mortgage Lenders (CML) compliant. That means a modern tank that treats the wastewater in such a way that it can be discharged without problems.

This reluctance to lend can easily break the chain of a house sale. What you thought was a signed and sealed sale suddenly falls apart because your buyers simply can’t get the mortgage money they need to go ahead.

How much longer will it take to sell a house with a septic tank

It’s no secret that the more potential buyers there are for a property the faster it will sell and the better the price it will achieve. When it comes to selling a house with a septic tank there are a few reasons that can push the sale time substantially beyond what would be expected for an average property sale.

The first of these reasons is location. Generally speaking houses that require a septic tank i.e. one not connected to a centralised sewage system, will be situated away from densely populated areas such as towns and cities. Rural properties will typically take longer to sell than their city counterparts as there is naturally less demand for them, that’s not to say that they are less desirable but fewer people are willing to take on long commutes for work and workplaces are usually in more populated areas. It is not surprising that a substantial number of the top 10 slowest selling postcodes are situated in rural areas, many with an average selling time of over a year and a half.

Another factor to consider is the septic tank itself, as previously stated a buyer might find it difficult to get a mortgage to purchase a property with an out of date or non compliant septic tank, this limits the sale to cash buyers further reducing the number of people that are actually in a position to purchase the property, increasing the sale time.

Even if you do find the proverbial hens teeth and secure a buyer the conveyancing time could also be substantially increased with the additional checks that the solicitors will need to carry out to make sure that the septic tank is up to standard, after all they are acting in the best interest of their client i.e. the buyer.

All in all it could take well over a year, if not two before the right buyer comes along and then several months more before the sale reaches completion. There is a way that you can speed up this process if you are in need of a fast sale, which I’ll get onto later.

Do you need to declare a septic tank when selling a house?

With all this in mind, you might be tempted to just try and hide your septic tank problems and hope that no one notices. This is not a good idea. You are legally obliged to tell potential buyers about your septic tank, under the Consumer Protection from Unfair Trading Regulations, and if you don’t, they can sue you.

You need to detail, in writing, where the tank is, where it drains to, when it was installed, when it was serviced and any problems you have had with the system.

There’s no point being ‘economical with the truth’ here either. As soon as a septic tank is mentioned, your buyers will commission what is known as a Homebuyers Drainage Survey. If you haven’t been completely honest with your buyers, this will soon expose the full story, and the game will be over – and so will your sale.

If you want to maintain the trust of potential buyers, you have to be upfront, even if this means your house will take considerably longer to sell.

Septic tank inspection for house sale – septic tank surveys

Any potential buyer of a property with a septic tank is likely to want to get a survey before they continue with the sale, the specific survey required for a septic tank inspection is called a ‘home buyer drainage survey’. This will involve a visit to the property of a qualified drainage engineer who will investigate the existing drainage system and then right up a report which will include;

Site diagram of the drainage system.
Sizing check to see if the septic tank is adequately sized for the dwelling.
Regulation compliance check that states if the system is compliant with the 2020 general binding regulations
Condition / Damage report
Any recommendations

It is worth noting that you can also get your own report called a ‘home seller drainage survey’ which will cover all of the same areas as the buyer report, you can either have this carried out if you disagree with anything in the buyers survey or you could have it carried out ahead of time so you know exactly what the situation is when you come to sell it. These reports cost anywhere from £500 upwards and it is worth noting that the septic tank will need to be emptied for the survey to take place.

The risk of a sub-standard septic tank

Many homeowners with septic tanks have simply ignored the new rules and hidden their heads in the sand, thinking that no one will ever notice. This might seem like a fair response, but if your outdated septic tank goes on to cause pollution, you can face an unlimited fine as well as all the costs for cleaning up the mess. You can bet that this will be way more expensive than bringing your tank up to standard, but many people still take the gamble.

Pollution from an outdated septic tank can lead to a fine and substantial clean up costs

The real problem for these people comes when they decide to sell their home. It’s not illegal to sell a home with a septic tank that does not meet the General Binding Rules, but it IS now illegal to have a septic tank that falls short of the GBR standard in the first place. So even if you’ve been quietly getting away with it up until now, putting your home on the market will shine an all-too-revealing spotlight on your wastewater arrangements.

How much it costs to replace a septic tank in the UK

As you can imagine replacing an out of date septic tank with a brand new sewage treatment plant is not a cheap affair. The unit itself can set you back anywhere between £2500 – £5000 and that’s the reasonable bit.

Depending on the size of the tank that is being replaced, its position and where the waste needs to be discharged the installation costs can reach up to £10,000 and beyond.

Item
Domestic sewage treatment unit
Simple Installation
Complex Installation

Cost
£2500 – £5000
£9,000 – £11,000
£11,000 – £13,000

Such eye watering costs make it easy to see why potential buyers are few and far between.

Selling a house with a shared septic tank

If you share a septic tank with one or more neighbours then your life just got a little more complicated. Not only do you still need to comply with the General Binding Rules but now you have to get all parties involved to agree on what to do. Although it can be beneficial if you all agree to split the costs it can slow the process down considerably, especially if you have a neighbour who would rather bury their head in the sand.

Septic tank replacement grant UK

Despite the new regulations coming into force with immediate effect in 2020 there are currently no financial incentives or grants in place to encourage owners to upgrade their septic tanks to meet requirements. Instead the burden is placed on the owner when it comes time to sell the property and unless the owner has tens of thousands lying around to address the issue the costs will likely have to be absorbed in the asking price or funded by the sale of the property.

The quick way to sell a house with a septic tank

As I mentioned earlier there is a fast way to sell a house with a septic tank, even a non compliant one and that is through a house buying company. These companies purchase properties with any number of issue including septic tanks.

The speed and the situation will be reflected in the price that they will offer but if you need to sell up and move on with your life it might not be such a bad deal, especially when you compare it to a lengthy open market sale.

Summary

Selling a house with a septic tank is possible but it may take longer and there may be some compliance issues that need to be taken care of either by you as the seller or by the buyer which will effect the sale price that you get or the costs that you will need to outlay prior.

A sale of a property with a septic tank will likely take many months longer than a house connected to the main sewage system. If you need a faster than normal sale you do have the option of selling to a house buying company but you will get around 80% of the market value of the property but the sale can happen in as little as 2-3 weeks if desired or longer if needed.

If you think that a sale to a house buying company might be an option for you then you can read further articles on this website and use our other resources such as our downloadable ‘step by step guide to finding a legitimate house buying company’ which you can find on the free resources page.

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Frequently Asked Questions

What is a septic tank?

Septic tanks are a drainage system that take all of the wastewater from your home that would normally go into the sewers or the drains. This includes water from baths and showers, dishwashers and washing machines. It also takes all the waste that you flush down the loo that most homes never have to think about again.

The septic tank separates the waste and discharges the water part into a drainage field or into the local watercourse, such as a river or a ditch. The remaining waste has to be emptied on a regular basis. Modern septic tanks treat the wastewater so that it is safe to be discharged into the environment, but many older tanks don’t do this, and this is where the problems start.

What is the difference between a septic tank and a cesspit?

The difference between a septic tank and a cesspit is that a septic tank has an outlet where the collected waste water is separated and discharged. A cesspit on the other hand is just a holding tank which generally requires emptying at a higher frequency that a septic tank.

Do houses with septic tanks sell?

Yes. Houses with septic tanks do sell but it can take considerably longer to agree a sale. If you need to sell your house with a septic tank fast then a house buying service could be your best option.