Selling or Buying a House With a Septic Tank: What to Check

The general binding rules

If you operate a septic tank or small sewage treatment plant in England, you do not need a permit as long as you meet all of the general binding rules that apply to you. Which rules apply depends on whether your system discharges to the ground or to a surface water (such as a river, stream, lake or canal), and on when the discharge started: before 1 January 2015, between 1 January 2015 and 2 October 2023, or on or after 2 October 2023.

If you are selling: tell the new owner in writing

The rules say that if you sell your property, you must tell the new operator in writing that a sewage discharge is in place. GOV.UK lists what to include:

• A description of the treatment plant and drainage system
• The location of the main parts of the system and the discharge point
• Details of any changes made to the system
• How the system should be maintained, and the maintenance manual if you have one
• Maintenance records, if you have them

Septic tanks that discharge to a watercourse

GOV.UK says that if you have a septic tank that discharges directly to a watercourse, you need to take action as soon as possible to meet the requirements. It also says that where such properties are sold, responsibility for replacing or upgrading the system should be addressed between the buyer and seller as a condition of sale. That is why it is often raised during conveyancing.

Emptying

The rules say the sludge that builds up must be removed before it goes beyond the maximum capacity, at least once a year or in line with the manufacturer’s instructions, and that the company that takes the sludge away must be a registered waste carrier. GOV.UK suggests asking the company to confirm this, or asking the tanker driver for a copy of the waste carrier’s certificate.

Installing a new system

GOV.UK says you must have Building Regulations approval if you install a new sewage treatment plant, and you may also need planning permission.

A checklist for buyers and sellers

• Find out whether the system is a septic tank or a sewage treatment plant.
• Find out where it discharges: to the ground (for example a drainage field) or to a surface water such as a ditch or stream.
• Ask for the written details and any maintenance and emptying records.
• If a septic tank discharges directly to a watercourse, agree who will deal with replacing or upgrading it.

How we can help

We carry out the groundwork for septic tank replacement and sewage treatment plant installation: excavation, base preparation, setting the plant, inspection chambers, pipework and reinstatement.