Selling a house with Japanese knotweed

You can sell a house with Japanese knotweed, but you must declare it on the TA6 property information form, and that applies even after it's been treated. The good news is that the way surveyors and lenders deal with knotweed changed in 2022. With a professional management plan in place, most buyers can still get a mortgage, though the price may reflect the cost and the stigma.

This guide covers the law, what to declare, how the current RICS rules work, management plans and your options for selling in England and Wales.

Is it illegal to have Japanese knotweed?

No. GOV.UK guidance for England says you don't legally have to remove Japanese knotweed from your land unless it's causing a nuisance. But you must stop it spreading off your property, and you can be prosecuted for causing it to spread into the wild.

Knotweed waste needs care too. Soil or plant material containing it may count as controlled waste, so it has to be disposed of properly, and soil containing it mustn't be sold as topsoil. Wales has its own guidance, which GOV.UK links to.

What you must tell buyers

The Law Society's TA6 property information form asks whether the property is affected by Japanese knotweed and, if so, whether there's a management plan in place. Since 30 March 2026, firms in the Law Society's Conveyancing Quality Scheme have had to use the 6th edition of the form for new sales.

Three points matter most:

• Nearby growth counts. The Law Society's notes say a property is usually treated as at risk if knotweed is growing on it or within three metres of its boundary.
• "No" means you're sure. Knotweed roots can be present underground even when nothing shows above ground. If you can't be certain, answer "not known".
• Treated knotweed still counts. RICS says that even after successful treatment, knotweed must be declared when the house is sold.

Getting this wrong can be expensive. Under the Misrepresentation Act 1967, a buyer who relied on a false answer may be able to claim compensation from you, and in serious cases a court can set the sale aside. If knotweed has ever been present, tell your solicitor and let them help with the wording. Our guide to the TA6 property information form covers the rest of the form.

How surveyors and lenders assess knotweed now

For ten years, surveyors used a 2012 RICS paper that focused on how close knotweed was to buildings and boundaries, using a 7-metre distance. That was replaced by the RICS standard Japanese knotweed and residential property, effective from 23 March 2022 and reissued as a professional standard in October 2022 without material changes. It's still the current version.

The standard focuses on what the knotweed is actually doing, and puts it into one of four management categories:

Category	What the surveyor finds	What RICS expects of lenders
A: Action	Knotweed is causing visible damage to a structure, such as the house, a garage or a boundary wall	Most lenders likely to want a management plan with insurance-backed cover, and may hold back part of the loan until it's in place
B: Action	Knotweed is likely to stop you using, or getting to, garden or outdoor space such as lawns, paths and driveways	As for Category A
C: Manage	Knotweed is on the property but not damaging structures or affecting amenity space	No treatment should be required as a condition of the mortgage, though specialist advice is still recommended
D: Report	Knotweed is not on the property but is on neighbouring land within 3 metres of the boundary	Reported to the lender, but only in exceptional cases a condition of the mortgage

If knotweed is next door and more than 3 metres from the boundary, a mortgage valuer normally just makes a note. RICS also points out that knotweed can't grow through intact concrete and often just grows through cracks that were already there, so finding it next to damage doesn't always mean it caused it.

Lenders still set their own policies, so the categories are guidance, not a promise. RICS designed them to give lenders a clearer, more proportionate basis for decisions than the old distance rule.

Management plans: what lenders and buyers look for

A Japanese Knotweed Management Plan sets out how the knotweed will be treated and monitored. Treatment often takes several growing seasons, and the realistic aim is usually effective control rather than complete eradication. The RICS standard says lenders are reassured by a plan that:

• is drawn up by a specialist who belongs to a recognised trade body
• covers the whole property, not just the patch the valuer saw
• can be transferred to the next owner
• is paid for up front by the current owner, so the buyer isn't left funding it
• comes with a warranty from the contractor lasting at least five years after the work is finished, backed by insurance so it stays valid if the contractor stops trading
• keeps a treatment record, and ends with a certificate after a two-year period with no growth

If you already have a plan, gather the contract, treatment records and the insurance-backed warranty paperwork for your solicitor. If you don't, getting one in place before you market the house usually makes buyers and lenders much more comfortable.

Knotweed on a neighbour's land

If the knotweed is next door, you can't treat it yourself. Talk to your neighbour first: GOV.UK says landowners must stop knotweed on their land spreading off their property. If it's within three metres of your boundary, declare it on the TA6, and keep a record of your conversations. A valuer would put it in Category D, which RICS says shouldn't normally be a condition of a mortgage.

Should you treat it before you sell?

Usually, yes, if you have time. A plan that's under way, with insurance-backed cover that transfers to the buyer, answers the questions that otherwise put buyers off. RICS notes that some stigma can remain even after treatment, but that any effect on value tends to be smaller than before and to fade over time.

If you can't wait for treatment to be arranged, or the infestation is large, selling as it is is still possible. It just narrows the field to buyers who are comfortable with knotweed, and they'll price in the cost and the risk.

Your options for selling

Route	Price	Speed	Good for
Estate agent	Usually the highest, especially with a transferable plan in place	Often several months	Category C or D, or A and B with a plan under way
Auction	Can attract buyers who expect problems; fees and no certain price	Weeks once listed	Large or untreated infestations
Cash buying company	Usually below market value	Can complete in weeks	Sellers who want a quick, certain sale without arranging treatment

When an estate agent is likely to be better: if the knotweed is minor, next door, or already covered by a transferable management plan, the open market usually gets more.

When a quick sale can make sense: if a sale has fallen through over knotweed, the infestation is serious, or you can't wait for a plan. It doesn't suit someone who could get a plan in place and sell on the open market for more.

We buy homes as they are, including those affected by knotweed, and make an offer within 24 hours. We pay your legal fees, and there's no obligation to accept. Our offer is below market value, and we explain how we worked it out from recent sales nearby. Read about below market value offers to see what that means in practice.

A checklist for selling a house with knotweed

• Find out where the knotweed is: on your land, next door, or both
• Get a specialist survey and a management plan if you don't have one
• Gather the plan, treatment records and insurance-backed warranty paperwork
• Check the plan transfers to a buyer, and tell the contractor you're selling
• Answer the TA6 knotweed questions with your solicitor's help, using "not known" if unsure
• Keep a record of any conversations with neighbours about knotweed on their land
• Dispose of any knotweed waste following the GOV.UK rules

If the house isn't selling, our guide to a house not selling covers the fixes worth trying before you change route.