Buying a property in the countryside or a rural location often comes with unique considerations, one of which is whether the property is connected to mains sewerage.

Many homes instead rely on a private drainage system such as a septic tank, sewage treatment plant or cesspit. While this is perfectly common, it is important to understand how these systems work, what legal responsibilities they carry and what your conveyancer will need to investigate before you exchange contracts.

In this guide, I will explain what it means to buy a house that is not connected to mains sewerage, the checks that should be carried out during the conveyancing process, and how you can avoid unexpected costs or delays when purchasing a rural property.

What Does It Mean If a Property Is Not Connected to Mains Sewerage?

The majority of properties in built up areas are located near to the main sewers which means that the waste water and solids produced by your home will drain to the public sewer and from there be treated at a sewerage plant. You will receive a regular bill from the sewerage provider charging you an amount to treat the sewerage. You do not have to do anything further.

However, not all properties are connected to mains sewers. If you live in one of those properties, the waste water and solids will drain to a tank sited nearby, often within the property boundaries, and it will be your responsibility to arrange for its disposal by a licensed contractor.

Having a private drainage system at a property does not necessarily affect property value. This will depend on how old the system is and how well the tank functions.

Types of Private Drainage Systems

There are three types of private drainage systems :

Septic Tank

This is a large tank located underground and will collect the waste sewerage from your property which will drain into the tank where it will be treated. It works by separating the solids from the liquids, allowing bacteria to break down the waste before the liquid is discharged into a drainage field and the solid is collected by a licensed waste contractor.

This is the most common type of treatment plant for properties that are not connected to main sewerage.

Advantages of Septic Tank :

Generally less expensive to install than connecting to the main sewer
Usually are Eco-Friendly and uses natural processes to break down the waste and discharge the waste water to ground through natural filtration.
With regular maintenance can last for 15-40 years
On average, septic tank will need emptying every 2-3 years.

Disadvantages of Septic Tank :

Need regular maintenance to avoid blockages and the sewerage becoming clogged and backed up. This can lead to foul odours.
Lack of regular maintenance can lead to costly repairs.
Large households can exceed the tank capacity and daily limits imposed by the general binding rules.
Poorly designed or maintained systems, and old tanks, can contaminate groundwater and surrounding soil.
Need a licenced waste contractor to empty the tank.
Geological area can affect the efficiency of the tank.

Cess pit

This is similar to a septic tank in that it is a large tank located underground that will collect the sewerage and waste water from your property. However the tank is sealed and does not discharge the waste water into the environment. Unlike a septic tank, it does not treat waste but simply holds it until it is emptied by a licensed waste contractor.

Advantages of Cess Pit :

Easy to install and do not require a drainage field making them ideal for homes with poor ground drainage or limited space.

Disadvantages of Cess Pit

Require more frequent emptying which can lead to higher long term costs.
If not property managed they can overflow and pollute the surrounding areas
Produce bad odours if not maintained property or emptied frequently, causing a nuisance.

Sewerage Treatment Plant

This is a system that will process waste water to remove contaminants before releasing treated water into the environment. Unlike septic tanks, which only separate solids from liquids and releases partially treated liquid to a drainage field, sewage treatment plants use biological and chemical processes to break down waste more effectively and produces much cleaner effluent meaning they can discharge to ground or surface water.

If the property is situated near to a water course, as sewage treatment plants meet stricter discharge rules, these will be permitted unlike septic tanks which are prohibited from discharging directly or indirectly into a water course.

Environmental benefits of Sewerage Treatment Plants

Proper treatment prevents water pollution and protects aquatic ecosystems.
Treated water can be reused for landscaping, reducing the demand on fresh water.
Modern plants are designed to control foul smells reducing the negative impact on neighbouring properties and nuisance complaints.
Some plants allow recovery of biogas from the sludge, which can then be used as an energy source.

What Your Conveyancer Will Check

The seller should disclose how foul sewerage and surface water is disposed of at the property in their Property Information Form which is sent to your Conveyancer at the start of the transaction with the contract pack. If the property is not connected to mains drainage, the seller will need to provide information about what happens and what type of system is in place.

The Property Information Form should be able to provide the following :

When was the system installed?
When was the last time the thank was emptied and maintained
Has it been regularly emptied and maintained?
Are there any ongoing repair issues?
Is the system shared with neighbouring properties?
Are maintenance records available?

Your water and drainage search will also confirm whether the property is connected to main drainage or not.

Once your conveyancer has established whether or not the property is serviced by a private drainage system, they will need to ask a few more questions to ensure the system both complies with the regulatory framework to dispose of foul water and surface water to land and that there are adequate legal rights in the title.

Very often more information will be required from the seller and the seller may need to provide documents to support its installation such as the building regulation completion certificate.

The General Binding Rules Explained

The General Binding Rules apply to small sewage treatment plants and septic tanks that discharge into the local environment. Its aim is to protect the natural and aquatic environment from contamination and pollution thus protecting our watercourses and wildlife from pollutants. They are a set of rules that must be followed from having the tank installed to its running and maintenance.

The General Binding Rules came into force on 1^st January 2015 and apply to both existing discharges (systems installed before 31^st January 2014) and new discharges (systems installed on or after 1^st January 2015).

The rules make it illegal to discharge directly into watercourses or ditches, and treated effluent (once it has passed through either septic tank or sewerage treatment plant) must be discharged to the ground via a drainage field – or soakaway.

Under the rules, if an existing system discharged directly into surface water, this needed to be replaced by 1^st January 2020 or when the property was sold, which ever came first.

If you purchase a property which does not comply with the general binding rules, by law the tank will need to be replaced by the seller before completion takes place.

The general binding rules will apply to all residential discharges from a septic tank or sewerage treatment plant. If the discharge is from a commercial property as well as a domestic house, for example a public house or bed and breakfast, the binding rules will not apply and you will have to apply for a permit from the Environment Agency.

The discharge must be less than 2 cubic metres a day in volume. If the discharge is greater than this again you will need to apply for a permit from the Environment Agency.

The discharge must not cause pollution of surface water or groundwater.

When you sell the property you must provide details of the type of tank, where it drains to and a record of maintenance. You will also need to provide the building regulation certificate for its installation.

If a property is located near to a watercourse, such as a river, stream, brook or reservoir, you may not be able to discharge to ground via septic tank but must discharge directly into the main sewers, or a sewerage treatment plant must be installed.

Questions to Ask Before Buying a Property with Private Drainage

It is important to research the type of private sewerage treatment fully before you purchase the property and make sure you are happy with the arrangement as it will become your responsibility to arrange for the emptying, maintenance and repair of the tank and all associated costs.

If the private sewerage plant serves more than one property, you may have to contribute towards the cost or carry out the works and request the neighbouring properties to reimburse you for their share of the cost of running, maintaining, repairing and emptying the tank.

Your Conveyancer will raise enquiries to find out the following information about the system:

When was the system installed
Has it been regularly emptied and maintained
Are there any ongoing repair issues
Is the system shared with neighbouring properties
Are maintenance records available

Common Problems Buyers Should Look Out For

Things to consider when purchasing a property serviced by a private drainage system:

How old is the tank – when will it need replacing. It can be expensive to replace a sewerage treatment plant and may require planning permission and building regulation consent.
What type of treatment plant is it. Is it fit for purpose. Does the waste water discharge to a drainage field and is there a watercourse nearby
What is the cost to maintain and empty the tank – find out the running costs and make sure you budget for the ongoing costs.
How often will it need maintaining and emptying. This is so that you can budget accordingly as it will be your responsibility to pay for its emptying, carry out regular servicing and repair.
Has the tank been maintained on a regular basis. By not maintaining the system on a regular basis may limit or reduce the life expectancy of the system and may result in a large cost to repair or replace the tank.
If the tank serves more than one property or is not located within the property boundaries you are buying, if there are no or insufficient rights to use the sewerage system, then these rights will need to be drafted by entering into a Deed of Easement between the house owner and the neighbouring property owner. This can take time and may incur additional legal costs in drafting the deed, and registering at Land Registry against the title.

Can You Get a Mortgage on a Property with Private Drainage?

There is no reason why a lender will not grant a mortgage on a property served by a private drainage system although they will require your conveyancer to ensure that the system complies with the General Binding Rules and Building Regulations. They will also require the system to be in good working order and not in need of repair as this could affect the valuation of the property, and their security.

What Are the Ongoing Costs?

When factoring the ongoing costs, you should consider how often the private drainage system will need emptying, maintaining and repair costs. If you have a sewage treatment plant, you will also need to consider the day to day running costs of electricity costs.

Buying a Rural Property with Confidence

Buying a rural property can be an exciting prospect, but countryside homes can sometimes involve additional considerations that you may not encounter when buying a property connected to mains services.

Understanding these arrangements before you commit to the purchase can help you avoid unexpected costs and potential delays. Your conveyancer can investigate the property's drainage arrangements and make sure you understand any responsibilities that will pass to you as the new owner.

Why specialist conveyancing advice matters

A property that is not connected to mains sewerage is not necessarily more difficult to buy but it can require additional enquiries and documentation. An experienced Conveyancer can identify potential issues with the private drainage system and investigate matters such as ownership, maintenance responsibilities, shared arrangements and rights of access.

This is particularly important where a septic tank or sewage treatment plant is shared with neighbouring properties or where part of the drainage system is located outside the property's boundaries. Understanding your legal rights and responsibilities before exchange of contracts can give you greater confidence in your purchase.

How early investigations can prevent delays

Raising questions about private drainage as early as possible can help prevent problems later in the conveyancing process. Your Conveyancer may need to obtain information from the seller about the drainage system including details of its installation, maintenance, servicing and any relevant agreements or consents.

If further documentation, enquiries or investigations are required, identifying this early gives the parties more time to resolve any issues before you are committed to the purchase. It can also help you understand whether there could be future repair, maintenance or replacement costs associated with the system.

How Timms Can Help

Purchasing a property with a private drainage system should not be a cause for concern, provided the right legal checks are carried out from the outset. At Timms, our experienced Conveyancing team regularly acts for buyers and sellers of rural and countryside properties, giving us a thorough understanding of the additional enquiries that may be required where a property is not connected to mains sewerage.

We will carefully review the property's drainage arrangements, investigate ownership and maintenance responsibilities, check for any shared drainage agreements or rights of access, and ensure the necessary documentation is in place. Where appropriate, we will raise additional enquiries with the seller, advise on compliance with the relevant environmental regulations, and identify any issues that could affect your purchase or future ownership.

Whether you are buying your first rural home or adding to your property portfolio, our aim is to make the conveyancing process as straightforward and stress-free as possible. By identifying potential issues early, we can help minimise delays and ensure you have a clear understanding of your legal obligations before you commit to the purchase.

If you are buying or selling a property with a septic tank, sewage treatment plant or other private drainage system, our friendly Conveyancing team is here to help.

Contact Timms today on freephone 0800 011 666 or via email at legal@timms-law.com to speak to one of our experienced Conveyancers and receive clear, practical advice tailored to your transaction. We will guide you through every stage of the process, helping you move forward with confidence.

Frequently Asked Questions

Can I buy a house with a septic tank?

Yes. Buying a house with a septic tank is common, particularly in rural areas where properties are not connected to mains sewerage. Before you purchase, your conveyancing solicitor will investigate the drainage arrangements, ownership, maintenance responsibilities and whether the system complies with the relevant environmental regulations.

Does a septic tank affect mortgage approval?

In most cases, no. Mortgage lenders are generally happy to lend on properties with private drainage systems, provided they are well maintained and comply with current regulations. If there are concerns about the condition or legality of the system, the lender may request further information or require any issues to be resolved before completion.

Who is responsible for maintaining a shared septic tank?

Responsibility depends on the legal agreements in place. If the septic tank is shared between neighbouring properties, there should be a clear agreement setting out who is responsible for maintenance, servicing and repair costs. Your conveyancing solicitor will review these arrangements during the purchase to ensure you understand your obligations.

How often does a septic tank need emptying?

Most septic tanks should be emptied approximately once a year, although the frequency depends on the size of the tank, the number of people using it and the manufacturer’s recommendations. Regular maintenance helps prevent blockages, prolongs the life of the system and reduces the risk of costly repairs.

Can an old septic tank fail environmental regulations?

Yes. Older septic tanks may not meet the current General Binding Rules or environmental standards, particularly if they discharge directly into a watercourse. If a system is non-compliant, the owner may need to repair, upgrade or replace it. Your conveyancing solicitor can identify any potential concerns during the legal process.

What happens if a private drainage system needs replacing?

If a private drainage system has reached the end of its lifespan or no longer complies with current regulations, it may need to be replaced. This can involve a significant cost, so it is important to understand the condition of the system before you buy. Your conveyancing solicitor can help identify potential issues and advise on any legal implications before you commit to the purchase.

Buying a House That Is Not Connected to Mains Sewerage: A Complete Guide for Homebuyers