Buying a UK Property With a Septic Tank or Private Drainage: What to Check
Some UK homes, mostly in rural areas, are not connected to the public sewer. They use a septic tank, a small sewage treatment plant or a cesspit instead. If you are buying one, you need to know which it is, who owns it and whether it meets the rules.
This Banke UK guide sets out the checks for buyers, including overseas buyers who cannot easily visit, and the questions to put to your solicitor.
The Short Answer
Ask the seller to confirm in writing what type of private drainage the property has, where it is, who maintains it and whether it is shared with neighbours. In England the rules on discharge are set by the Environment Agency, and in other parts of the UK by the equivalent body, so have your solicitor check that the system complies. A faulty or non-compliant system can mean a replacement bill for the new owner.
The Three Common Types
- Septic tank. Holds and partly treats waste, then releases liquid into the ground or a watercourse. Older tanks that discharge directly into a ditch or stream may no longer be allowed.
- Sewage treatment plant. A small powered unit that treats waste more fully. It needs electricity and servicing.
- Cesspit. A sealed tank that is emptied by tanker. It has no outlet, so running costs depend on how often it needs emptying.
What to Ask the Seller
- Which type of system is it, and how old is it?
- Where are the tank, the drainage field and any outlet, and who owns the land they sit on?
- Is it shared with another property, and is there a written agreement on maintenance and access?
- Where does it discharge, and has the seller registered or applied for any permit the rules require?
- When was it last emptied or serviced, and are there receipts?
What Your Solicitor Should Check
Your solicitor will usually raise drainage on the seller's property information form. Our guide to completing the TA6 form explains why the answers matter. They should also check rights of access for emptying and maintenance, and whether a drainage field crosses a neighbour's land. Our article on what UK property searches check shows which searches may confirm whether a mains connection exists.
Survey and Condition
A general survey may only note the presence of a system and say it was not inspected. Ask your surveyor whether a specialist drainage inspection is worth commissioning, particularly for older systems. Read about the survey levels in our guide to RICS home survey levels.
Running Costs and Risk
- Emptying, servicing and any electricity cost are the owner's.
- A system that needs replacing may be costly. Get a quote before exchange and use it in negotiation if needed.
- Flooding and high water tables can affect how well a system works. See our guide to flood risk, damp and subsidence.
- Mortgage lenders may ask questions about private drainage. Raise it with your broker early.
Buying From Abroad
If you cannot attend a viewing, ask for photographs of the tank and inspection covers, the servicing records and a short video from the agent. Your solicitor and surveyor can then do the checking on your behalf. Build any likely drainage work into the figures in our guide to the full cost of buying UK property from abroad.
Talk to Banke
To discuss a specific UK property, contact the Banke UK team.
This is general information, not legal, tax or financial advice. Rules and procedures change, so confirm current details with the relevant authority and an independent professional before you commit.