The short answer
You can sell a house with Japanese knotweed, but you must disclose it honestly on the TA6 Property Information Form. The most reliable route is to commission a PCA-accredited treatment plan with an insurance-backed guarantee (IBG) before marketing, so the buyer’s lender can proceed. Expect some price impact, but the 2022 RICS guidance means most affected homes are mortgageable and saleable when managed properly.
Selling a home affected by Japanese knotweed is entirely possible – thousands of such transactions complete each year. The two things that make or break the sale are honest disclosure and a credible plan to deal with the plant. Get both right and you keep your buyer, their lender and your conveyancer moving. This guide walks through disclosure duties, the documents that reassure a buyer’s lender, and how knotweed affects price.
Selling with knotweed at a glance
- Must you disclose? Yes – TA6 question 7.8
- Best preparation PCA plan + IBG before listing
- Buyer’s lender wants Plan + insurance-backed guarantee
- Price impact Often a diminution in value
- Risk of hiding it Misrepresentation claim
- Saleable? Yes, when properly managed
You must disclose – the TA6 form
When you sell, your conveyancer asks you to complete the Law Society’s TA6 Property Information Form. Question 7.8 specifically asks whether the property is, or has been, affected by Japanese knotweed. You must answer honestly. Replying ‘No’ when you know otherwise – or ‘Not known’ to dodge the issue when you do know – exposes you to a misrepresentation claim after completion. Our guide to the TA6 form and question 7.8 explains the wording and the duty in detail.
Prepare before you market
The single best move is to put the solution in place before the property goes on the market. That means:
- A survey and written treatment plan from a PCA-accredited specialist.
- An insurance-backed guarantee (IBG), typically 5–10 years, that the buyer’s lender can rely on.
- Documentation – the plan, IBG and any work already done – ready to hand to the buyer’s conveyancer.
This converts an open-ended worry into a defined, funded process, which is exactly what a buyer’s lender needs to lend – see getting a mortgage on a knotweed property.
How knotweed affects your price
There is usually some effect on value – surveyors call it a ‘diminution in value’ – reflecting the cost of treatment and any residual market stigma. The 2022 RICS guidance moved the market away from blanket devaluation toward a proportionate, risk-based view, so the impact is generally tied to the category and the cost of putting it right rather than a fixed percentage. Funding the treatment yourself, or adjusting the price to cover it, is often what gets the deal across the line. See how knotweed affects house value.
Your route to a completed sale
- Get a PCA-accredited survey and quote.
- Commission a treatment plan with an IBG.
- Disclose fully and accurately on the TA6.
- Provide the documents to the buyer’s side early.
- Be prepared to fund treatment or adjust price to keep the chain intact.
This is general information, not legal advice. Speak to your conveyancer about disclosure and have any infestation assessed by a PCA-accredited specialist.
Selling a home with knotweed?
Commission a PCA-accredited plan and IBG before you list. It satisfies the buyer’s lender, supports your TA6 disclosure and protects you from a later claim.
Frequently asked questions
Do I legally have to tell the buyer about Japanese knotweed?
Yes. The TA6 Property Information Form asks directly (question 7.8) whether the property is or has been affected. You must answer truthfully; a knowingly false answer can give the buyer a misrepresentation claim after completion.
Can I sell without treating the knotweed first?
You can, but most buyers’ lenders will want a plan and insurance-backed guarantee in place. Having those ready before marketing makes the sale far smoother than leaving the buyer to arrange them.
How much will knotweed knock off my sale price?
There is no fixed figure since the 2022 RICS guidance. The impact usually reflects treatment cost and any residual stigma rather than an automatic percentage. Funding the treatment yourself often minimises the effect on the agreed price.
What happens if I hide it and the buyer finds out later?
The buyer can bring a misrepresentation claim for the false statement on the TA6, potentially recovering damages. Concealment – including disguising treated growth – significantly increases that risk, so honest disclosure is always the safer course.
Sources & further reading
- The Law Society — TA6 Property Information Form (question 7.8, Japanese knotweed)
- RICS — Japanese knotweed and residential property, guidance note (2022)
- Property Care Association (PCA) — treatment plans & insurance-backed guarantees
- gov.uk — Prevent Japanese knotweed from spreading
This guide is general information, not a site-specific survey or legal advice. Japanese knotweed treatment and removal should be assessed by a PCA-accredited specialist before you act.