Expert Guide

Selling a property with a septic tank

Here are some things to consider if you’re planning to sell a property with off mains drainage.

Selling a property can be a stressful time, particularly if things don’t go smoothly. Last minute glitches or problems identified by a prospective purchaser can cause delays, reductions in sales price, or worse, they can cause the sale to fall through.

Septic tanks and other off mains drainage systems such as sewage treatment plants and cesspits can often be a cause of strife when selling a property. Why? Firstly, with them sat out of sight underground, often nobody knows what condition they are in. Uncertainty is the nemesis of smooth property sales. Secondly, they can be very expensive to repair or replace, so some prospective purchasers might see it as a potential liability.

Property sold with septic tank illustration

What are your responsibilities when selling a property with a septic tank?

There are some things which you are obliged to do under current legislation, and others which it may be advisable to do to ensure your sale goes smoothly. Firstly, we will outline the two main areas with which legislation says you must comply:

Telling the new owner about the drainage system in place

The General Binding Rules for Small Sewage Discharge state that, if selling a property with off mains drainage, you must tell the new owner in writing that a sewage discharge is in place.

The guidance states that you should include:

  • A description of the treatment plant and drainage system
  • The location of the main parts of the treatment plant, drainage system and discharge point (i.e. does the system discharge to ground, or to a nearby watercourse or ditch?)
  • Details of any changes made to the treatment plant and drainage system
  • Details of how the treatment plant should be maintained, and the maintenance manual if you have one
  • Maintenance records if you have them

If you have a septic tank, it will have required regular routine emptying, and it is useful to be able to demonstrate to a prospective purchaser that you have done so. This is because a septic tank which is regularly routinely emptied is likely to remain in a serviceable condition for longer than one which is not.

Some people keep receipts of routine empties, however this is not a requirement of you as the owner of the septic tank.

It is worthwhile gathering as much information as you can as to when the tank has been emptied, if you have used the same tank emptying company each time, they may be able to provide you with copies of receipts or confirmation of the dates they have emptied the tank.

Ensuring that your septic tank does not discharge straight to a watercourse

If you have a septic tank, you need to identify whether it discharges to a ditch or watercourse. If this is the case, the General Binding Rules state that the system must be replaced or upgraded by 1st January 2020. This is because it is no longer considered safe for the environment for a septic tank to discharge wastewater straight to a watercourse.

The Rules state `Where properties with septic tanks that discharge directly to surface water are sold before 1 January 2020, responsibility for the replacement or upgrade of the existing treatment system should be addressed between the buyer and seller as a condition of sale’ (you can view the full guidance notes here

Currently, there is no available guidance as to what should happen in respect of property sales beyond 1st January 2020, particularly given that there is not much awareness amongst property owners as to the changes. However, given that the Rules have been introduced to reduce risk to the environment, our advice would be to assume that the rules will continue to apply.

If you would like to know more about the regulations, and what your options might be, you can read our Guide to Septic Tank Regulations here.


How to discover the details and the condition of your system

So, what about the condition of the drainage system? How do you even know where the system runs, and what it is comprised of, such that you can inform a potential buyer of your property?

A standard buildings survey, carried out on behalf of a prospective purchaser, will only take a cursory look at any off mains drainage system that’s in place. Typically, the report will recommend that the buyer arranges a specialist drainage survey of the system – and this can be where delays or problems are experienced. Surveys of septic tanks can identify problems, either with the compliance or condition of the drainage system, which can be a stumbling block in any sale.

It’s important as the seller of the property to get on the front foot - both to protect yourself and the environment, in the instance that your drainage system is no longer compliant with new regulations. We recommend finding a specialist to carry out a survey of your drainage system, the findings of which you can act on if required, or present to any prospective purchasers of your property. The report should include:

  • A plan of the drainage system, and where it runs.
  • Identification of what type of tank is in place.
  • Where the system discharges to (if known).
  • A summary of the condition of the drainage system - this should include both the structural integrity of the tank, as well as the condition of any pipework where possible. The tank should be emptied at the same time that the survey is carried out - this is because it will enable the engineer to observe how the system responds to being emptied. Waste water returning to the tank from the soakaway system can be a sign that it is not performing as it should be.
  • Guidance on whether the system is compliant with applicable regulations.
  • A summary of any remedial works which might be required, and guidance as to costs.

What to do next

In summary, it is important when selling a property with a septic tank that you provide clear information to any prospective buyer as to what type of drainage system you have, its compliance with regulations, and the condition it is in. It is also beneficial to be able to demonstrate that you have appropriately maintained the system. It’s never too soon to start gathering the information required.

If you’re not sure where to start or just need some assistance then we can help. We offer a Home Seller Drainage Survey service which can help you to ensure that your property sale goes smoothly, that you maximise the sale price, and that you are complying with septic tank regulations.

Call our team on 01628 788600 and they’ll be delighted to answer any questions or get your survey booked in.

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UKDP team in office answering off mains drainage enquiries

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