Japanese knotweed
Can you assign a RICS knotweed category from a single photograph in the survey?
No. The categories in the 2022 standard depend on whether there is visible material damage to a significant structure, and on amenity, and on whether the plant is on or off the site. A photo of a cane does not measure damage or distance. The surveyor’s words, if they give a category, are the finding. If they do not, you do not invent one.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
The Property Journal piece on the standard is clear that the old seven-metre habit has been replaced and that off-site plants within three metres fall under category D, report. It also says that where the plant is within the boundaries a remediation specialist should advise. A buyer circling a photo and writing “category A” is doing neither the surveyor’s job nor the specialist’s.
Use the photograph to ask a better question: where was this, how far from the house, is a structure cracked, is amenity space blocked. Then let someone who applies the standard answer. GOV.UK’s duty not to spread the plant is not a category. Do not negotiate a price off a letter you have assigned yourself.
What should you ask your surveyor?
- Have you given a management category in the report, or only a photograph?
- Where was the plant relative to the boundary and the house?
- Did you see damage to a structure?
What are the typical next steps?
- Do not label the photo with a category in your offer.
- If the surveyor stopped at “possible”, get an identification.
- If a category is given, read what action that category requires and ask the specialist, rather than inventing a percentage off the price.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does category C mean do nothing?
The journal describes C as manage: the plant is not damaging a structure or amenity, and remediation is at the owner’s discretion. It still expects specialist advice where knotweed is within the boundaries.
Is a category a valuation?
No. The journal discusses how value may be affected. It does not publish a deduction. Your lender and the specialist’s quote are where numbers start.