Selling a house with a septic tank: Updated 2025 Advice

Wednesday, 8 October, 2025 | Gerry Rowe

This is an image of what you would see if you had this type of septic tank.

Why Septic Tanks Matter When Selling a Home

If your property has a septic tank, you must make sure it complies with the General Binding Rules that came into effect in January 2020. These rules are still in force today.

If you are planning to sell your house, the system must meet these standards before you can legally complete the sale. Failure to do so can delay the process, reduce the value of your property, or result in costly upgrades for the buyer.

At ASL Limited, we cover every septic tank service: installations, maintenance, desludging, repairs, and full replacements. If you’re selling a property with a septic tank, we can check compliance and carry out any work needed to keep your sale moving.

Call us today to find out more.

Key Points of the Current Regulations

Your septic tank must:

Discharge to the ground via a properly designed drainage field, not to surface water.
Handle domestic sewage only, with a discharge rate of two cubic metres or less per day.
Avoid causing pollution to surface water or groundwater.
Not be within 50 metres of a well, spring or borehole used for drinking water or food production.
Be installed and operated within the manufacturer’s specification.
Be maintained by a competent person.
Have waste sludge removed by an authorised waste carrier.
Be covered by a written notice to the new owner on sale, describing the system and its maintenance requirements.
Meet the relevant British Standards (BS EN 12566) that applied at the time of installation.

👉 Full details are available on the Gov.uk General Binding Rules website.

Building Regulations for New Systems

If you are replacing or installing a new septic tank, Building Regulations also apply. Key requirements include:

Septic tanks must be within 30m of an access point for emptying.
They must be installed at least 7m from any inhabited building.
They must be the right size for the property and provide suitable ventilation.
They must be constructed to prevent flooding, leaking, or contamination of water supplies.

Steps to Take When Selling a Property with a Septic Tank

Locate your tank – Know exactly where it is and be able to show the new owner.
Check discharge point – Ensure it’s not discharging into a ditch or surface water (illegal since 2020).
Inspect the condition – Make sure it’s recently emptied, cleaned, and not damaged.
Gather maintenance records – Keep receipts for emptying, servicing, and repairs. These help reassure buyers.
Provide written notice – You must give the new owner details of the system and its maintenance requirements.

How ASL Can Help

If you’re selling a property with a septic tank in Guildford or within a 15-mile radius, ASL can:

Carry out a compliance inspection and issue the necessary paperwork.
Empty and service the system so it’s in good condition before sale.
Upgrade or replace outdated tanks with modern treatment plants that meet current regulations.
Provide written handover documents for the new owner.

📞 If you’re planning to sell your home and have a septic tank, call ASL on 0800 181684 (Freephone) or your local number.

We’ll make sure your system complies with the regulations and give you peace of mind that the sale can proceed smoothly.