Practical checklist · England
Septic tank selling checklist
Work through these items before your property sale progresses.
1. Identify the system
- Record whether it is a septic tank, sewage treatment plant or cesspool.
- Confirm whether the system serves only your property or is shared.
- Note who is responsible for maintenance and any shared septic tank arrangements, costs or access.
- Find installation or planning documents if they are available.
2. Map the important locations
- Locate the tank or treatment plant.
- Locate inspection covers, pipework and access for emptying.
- Identify the drainage field or discharge point.
- Keep a plan or clear photographs that can help the buyer understand the layout.
3. Understand the discharge
- Record whether the discharge goes to the ground or to surface water.
- Check that a discharge to ground uses a drainage field, not a rainwater soakaway.
- Remember that a septic tank must not discharge directly to a river, stream, ditch or other surface water.
- Get specialist advice if you cannot identify the route or suspect an issue.
4. Gather maintenance information
- Find the operating and maintenance manual.
- Gather emptying receipts and service or repair records.
- Record the date of the most recent emptying or service.
- Note any changes, replacements or repairs made to the system.
- Record any current warning lights, smells, backing up, wet ground or visible pollution.
5. Prepare the written information for the buyer
Official guidance says the seller must give the new operator:
- a description of the treatment and drainage system
- the location of the main parts and discharge point
- details of changes made to the system
- maintenance instructions
- maintenance records, if available
6. Resolve important gaps early
- Ask a qualified professional about an unclear, damaged or potentially polluting system.
- Discuss legal questions and sale conditions with your conveyancer.
- If a septic tank discharges directly to surface water, agree during the sale who will carry out the required upgrade.
- Do not describe a system as compliant unless an appropriately qualified adviser has confirmed what that means for your property.
Turn your notes into an organised seller pack
MySepticCheck guides you through the information, highlights gaps and brings your answers and evidence into one property record.
Official guidance
Check the Environment Agency rules for discharges to the ground and discharges to surface water.
Guidance reviewed 3 September 2026. This checklist is for properties in England and is not exhaustive. MySepticCheck is an information and readiness tool, not a compliance certificate, survey, physical inspection or legal or environmental advice.